1.
Apple II series
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Introduced at the West Coast Computer Faire on April 16,1977, the Apple II was among the first successful personal computers, it launched the Apple company into a successful business. Throughout the years, a number of models were sold, with the most popular model remaining relatively little changed into the 1990s, while primarily an 8-bit computer, by mid-run a 16-bit model was introduced. It was first sold on June 10,1977, by the end of production in 1993, somewhere between five and six million Apple II series computers had been produced. The Apple II was one of the longest running mass-produced home computer series, the Apple II became one of several recognizable and successful computers during the 1980s and early 1990s, although this was mainly limited to the USA. The original Apple II operating system was in ROM along with Integer BASIC, programs were entered, then saved and loaded on cassette tape. When the Disk II was implemented in 1978 by Steve Wozniak, the final and most popular version of this software was Apple DOS3.3. Some commercial Apple II software booted directly and did not use standard DOS formats and this discouraged the copying or modifying of the software on the disks and improved loading speed. Apple DOS was superseded by ProDOS, which supported a hierarchical filesystem, with an optional third-party Z80-based expansion card the Apple II could boot into the CP/M operating system and run WordStar, dBase II, and other CP/M software. At the height of its evolution, towards the late 1980s, by 1992, the platform had 16-bit processing capabilities, a mouse-driven graphical user interface, and graphics and sound capabilities far beyond the original. At its peak, it was an industry with its associated community of third-party developers and retailers. The Apple IIGS was sold until the end of 1992, the last II-series Apple in production, total Apple II sales for its 14-year run were about 6 million units, with the peak occurring in 1983 when 1 million were sold. The Apple II was designed to more like a home appliance than a piece of electronic equipment. The Apple II had color and high-resolution graphics modes, sound capabilities, the Apple II was targeted for the masses rather than just hobbyists and engineers, it also influenced most of the microcomputers that followed it. Unlike preceding home microcomputers, it was sold as a consumer appliance rather than as a kit. VanLOVEs Apple Handbook and The Apple Educators Guide by Gerald VanDiver, the Apple dealer network used this book to emphasize the growing software developer base in education and personal use. The Apple II series had a built into the motherboard shell. An upgrade kit was later to house the motherboard of an Apple IIGS in an Apple IIe case. The Apple II case was durable enough, according to a 1981 Apple ad, early II-series models were usually designated Apple ][ plus
2.
Lausanne
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Lausanne is a city in the French-speaking part of Switzerland, and the capital and biggest city of the canton of Vaud. The city is situated on the shores of Lake Geneva and it faces the French town of Évian-les-Bains, with the Jura Mountains to its north-west. Lausanne is located 62 kilometres northeast of Geneva, Lausanne has a population of 146,372, making it the fourth largest city in Switzerland, with the entire agglomeration area having 420,000 inhabitants. The metropolitan area of Lausanne-Geneva was over 1.2 million inhabitants in 2000, Lausanne is a focus of international sport, hosting the International Olympic Committee, the Court of Arbitration for Sport and some 55 international sport associations. It lies in a noted wine-growing region, the city has a 28-station metro system, making it the smallest city in the world to have a rapid transit system. Lausanne will host the 2020 Winter Youth Olympics, by the 2nd century AD it was known as vikanor Lousonnensium and in 280 as lacu Lausonio. By 400 it was civitas Lausanna and in 990 it was mentioned as Losanna, after the fall of the Roman Empire, insecurity forced the transfer of Lausanne to its current centre, a hilly site that is easier to defend. The city which emerged from the camp was ruled by the Dukes of Savoy, then it came under Bern from 1536 to 1798 and a number of its cultural treasures, including the hanging tapestries in the Cathedral, were permanently removed. Lausanne has made a number of requests to recover them, after the revocation of the Edict of Nantes in 1685, Lausanne became a place of refuge for French Huguenots. In 1729 a seminary was opened by Antoine Court and Benjamin Duplan, by 1750 ninety pastors had been sent back to France to work clandestinely, this number would rise to four hundred. Official persecution ended in 1787, a faculty of Protestant theology was established at Montauban in 1808, during the Napoleonic Wars, the citys status changed. In 1803, it became the capital of a newly formed Swiss canton, in 1964 the city hosted the Swiss National Exhibition, displaying its newly found confidence to host major international events. From the 1950s to 1970s a large number of Italians, Spaniards and Portuguese immigrated, settling mostly in the district of Renens. The city has served as a refuge for European artists, while under the care of a psychiatrist at Lausanne, T. S. Eliot composed most of his 1922 poem The Wasteland. Hemingway also visited from Paris with his wife during the 1920s, in fact, many creative people - such as Edward Gibbon, an historian, and Romantic era poets Shelley and Byron - have sojourned, lived, and worked in Lausanne or nearby. The city has been quiet, but in the late 1960s. Later demonstrations took place to protest against the high cinema prices, the most important geographical feature of the area surrounding Lausanne is Lake Geneva. Lausanne boasts a dramatic panorama over the lake and the Alps, in addition to its generally southward-sloping layout, the centre of the city is the site of an ancient river, the Flon, which has been covered since the 19th century
3.
Apple Inc.
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Apple is an American multinational technology company headquartered in Cupertino, California that designs, develops, and sells consumer electronics, computer software, and online services. Apples consumer software includes the macOS and iOS operating systems, the media player, the Safari web browser. Its online services include the iTunes Store, the iOS App Store and Mac App Store, Apple Music, Apple was founded by Steve Jobs, Steve Wozniak, and Ronald Wayne in April 1976 to develop and sell personal computers. It was incorporated as Apple Computer, Inc. in January 1977, Apple joined the Dow Jones Industrial Average in March 2015. In November 2014, Apple became the first U. S. company to be valued at over US$700 billion in addition to being the largest publicly traded corporation in the world by market capitalization. The company employs 115,000 full-time employees as of July 2015 and it operates the online Apple Store and iTunes Store, the latter of which is the worlds largest music retailer. Consumers use more than one billion Apple products worldwide as of March 2016, Apples worldwide annual revenue totaled $233 billion for the fiscal year ending in September 2015. This revenue accounts for approximately 1. 25% of the total United States GDP.1 billion, the corporation receives significant criticism regarding the labor practices of its contractors and its environmental and business practices, including the origins of source materials. Apple was founded on April 1,1976, by Steve Jobs, Steve Wozniak, the Apple I kits were computers single-handedly designed and hand-built by Wozniak and first shown to the public at the Homebrew Computer Club. The Apple I was sold as a motherboard, which was less than what is now considered a personal computer. The Apple I went on sale in July 1976 and was market-priced at $666.66, Apple was incorporated January 3,1977, without Wayne, who sold his share of the company back to Jobs and Wozniak for $800. Multimillionaire Mike Markkula provided essential business expertise and funding of $250,000 during the incorporation of Apple, during the first five years of operations revenues grew exponentially, doubling about every four months. Between September 1977 and September 1980 yearly sales grew from $775,000 to $118m, the Apple II, also invented by Wozniak, was introduced on April 16,1977, at the first West Coast Computer Faire. It differed from its rivals, the TRS-80 and Commodore PET, because of its character cell-based color graphics. While early Apple II models used ordinary cassette tapes as storage devices, they were superseded by the introduction of a 5 1/4 inch floppy disk drive and interface called the Disk II. The Apple II was chosen to be the platform for the first killer app of the business world, VisiCalc. VisiCalc created a market for the Apple II and gave home users an additional reason to buy an Apple II. Before VisiCalc, Apple had been a distant third place competitor to Commodore, by the end of the 1970s, Apple had a staff of computer designers and a production line
4.
Operating system
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An operating system is system software that manages computer hardware and software resources and provides common services for computer programs. All computer programs, excluding firmware, require a system to function. Operating systems are found on many devices that contain a computer – from cellular phones, the dominant desktop operating system is Microsoft Windows with a market share of around 83. 3%. MacOS by Apple Inc. is in place, and the varieties of Linux is in third position. Linux distributions are dominant in the server and supercomputing sectors, other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can run one program at a time. Multi-tasking may be characterized in preemptive and co-operative types, in preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, e. g. Solaris, Linux, cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking, 32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem, a distributed operating system manages a group of distinct computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing, distributed computations are carried out on more than one machine. When computers in a work in cooperation, they form a distributed system. The technique is used both in virtualization and cloud computing management, and is common in large server warehouses, embedded operating systems are designed to be used in embedded computer systems. They are designed to operate on small machines like PDAs with less autonomy and they are able to operate with a limited number of resources. They are very compact and extremely efficient by design, Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is a system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could run different programs in succession to speed up processing
5.
Central processing unit
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The computer industry has used the term central processing unit at least since the early 1960s. The form, design and implementation of CPUs have changed over the course of their history, most modern CPUs are microprocessors, meaning they are contained on a single integrated circuit chip. An IC that contains a CPU may also contain memory, peripheral interfaces, some computers employ a multi-core processor, which is a single chip containing two or more CPUs called cores, in that context, one can speak of such single chips as sockets. Array processors or vector processors have multiple processors that operate in parallel, there also exists the concept of virtual CPUs which are an abstraction of dynamical aggregated computational resources. Early computers such as the ENIAC had to be rewired to perform different tasks. Since the term CPU is generally defined as a device for software execution, the idea of a stored-program computer was already present in the design of J. Presper Eckert and John William Mauchlys ENIAC, but was initially omitted so that it could be finished sooner. On June 30,1945, before ENIAC was made, mathematician John von Neumann distributed the paper entitled First Draft of a Report on the EDVAC and it was the outline of a stored-program computer that would eventually be completed in August 1949. EDVAC was designed to perform a number of instructions of various types. Significantly, the programs written for EDVAC were to be stored in high-speed computer memory rather than specified by the wiring of the computer. This overcame a severe limitation of ENIAC, which was the considerable time, with von Neumanns design, the program that EDVAC ran could be changed simply by changing the contents of the memory. Early CPUs were custom designs used as part of a larger, however, this method of designing custom CPUs for a particular application has largely given way to the development of multi-purpose processors produced in large quantities. This standardization began in the era of discrete transistor mainframes and minicomputers and has accelerated with the popularization of the integrated circuit. The IC has allowed increasingly complex CPUs to be designed and manufactured to tolerances on the order of nanometers, both the miniaturization and standardization of CPUs have increased the presence of digital devices in modern life far beyond the limited application of dedicated computing machines. Modern microprocessors appear in electronic devices ranging from automobiles to cellphones, the so-called Harvard architecture of the Harvard Mark I, which was completed before EDVAC, also utilized a stored-program design using punched paper tape rather than electronic memory. Relays and vacuum tubes were used as switching elements, a useful computer requires thousands or tens of thousands of switching devices. The overall speed of a system is dependent on the speed of the switches, tube computers like EDVAC tended to average eight hours between failures, whereas relay computers like the Harvard Mark I failed very rarely. In the end, tube-based CPUs became dominant because the significant speed advantages afforded generally outweighed the reliability problems, most of these early synchronous CPUs ran at low clock rates compared to modern microelectronic designs. Clock signal frequencies ranging from 100 kHz to 4 MHz were very common at this time, the design complexity of CPUs increased as various technologies facilitated building smaller and more reliable electronic devices
6.
MOS Technology 6502
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The MOS Technology 6502 is an 8-bit microprocessor that was designed by a small team led by Chuck Peddle for MOS Technology. When it was introduced in 1975, the 6502 was, by a considerable margin and it initially sold for less than one-sixth the cost of competing designs from larger companies, such as Motorola and Intel, and caused rapid decreases in pricing across the entire processor market. Along with the Zilog Z80, it sparked a series of projects that resulted in the computer revolution of the early 1980s. Popular home video consoles and computers, such as Atari, Apple II, Nintendo Entertainment System, Commodore PET and others. Soon after the 6502s introduction, MOS Technology was purchased outright by Commodore International, in the early days of the 6502, it was second-sourced by Rockwell and Synertek, and later licensed to other companies. The 6502 was designed by many of the engineers that had designed the Motorola 6800 microprocessor family. Motorola started the 6800 microprocessor project in 1971 with Tom Bennett as the main architect, the chip layout began in late 1972, the first 6800 chips were fabricated in February 1974 and the full family was officially released in November 1974. John Buchanan was the designer of the 6800 chip and Rod Orgill, Bill Mensch joined Motorola in June 1971 after graduating from the University of Arizona. His first assignment was helping define the peripheral ICs for the 6800 family, Motorolas engineers could run analog and digital simulations on an IBM 370-165 mainframe computer. Bennett hired Chuck Peddle in 1973 to do architectural work on the 6800 family products already in progress. He contributed in areas, including the design of the 6850 ACIA. Motorolas target customers were established electronics companies such as Hewlett-Packard, Tektronix, TRW, in May 1972, Motorolas engineers began visiting select customers and sharing the details of their proposed 8-bit microprocessor system with ROM, RAM, parallel and serial interfaces. In early 1974, they provided engineering samples of the chips so that customers could prototype their designs, Motorolas total product family strategy did not focus on the price of the microprocessor, but on reducing the customers total design cost. They offered development software on a computer, the EXORciser system debugging system, onsite training. Both Intel and Motorola had initially announced a price for a single microprocessor. The actual price for production quantities was much less, Motorola offered a design kit containing the 6800 with six support chips for $300. Peddle, who would accompany the people on customer visits. To lower the price, the IC chip size would have to shrink so that more chips could be produced on each silicon wafer and this could be done by removing inessential features in the 6800 and using a newer fabrication technology, depletion-mode MOS transistors
7.
Compact Cassette
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The Compact Cassette or Musicassette, also commonly called cassette tape, audio cassette, or simply tape or cassette, is an analog magnetic tape recording format for audio recording and playback. It was released by Philips in 1962, having developed in Hasselt. Compact cassettes come in two forms, either already containing content as a cassette, or as a fully recordable blank cassette. Its uses ranged from portable audio to home recording to data storage for early microcomputers, the first cassette player designed for use in car dashes was introduced in 1968. Between the early 1970s and the early 2000s, the cassette was one of the two most common formats for prerecorded music, first alongside the LP record and later the compact disc. Compact Cassettes contain two miniature spools, between which a magnetically coated, polyester-type plastic film is passed and wound and these spools and their attendant parts are held inside a protective plastic shell. This reversal is achieved either by flipping the cassette, or by having the machine itself change the direction of tape movement. In 1935, decades before the introduction of the Compact Cassette, AEG released the first reel-to-reel tape recorder and it was based on the invention of the magnetic tape by Fritz Pfleumer, which used similar technology but with open reels. These instruments were expensive and relatively difficult to use and were therefore used mostly by professionals in radio stations. In 1958, following four years of development, RCA Victor introduced the stereo, quarter-inch, reversible, however, it was a large cassette, and offered few pre-recorded tapes. Despite the multiple versions, it failed, consumer use of tape only took off in the early 1960s, after playback machines reached a comfortable, user-friendly design. This was achieved primarily by the introduction of transistors which replaced the bulky, fragile, reel-to-reel tape then became more suitable to household use, but still remained an esoteric product. The team at Philips was led by Lou Ottens in Hasselt, Philips was competing with Telefunken and Grundig in a race to establish its cassette tape as the worldwide standard, and it wanted support from Japanese electronics manufacturers. However, the Philips Compact Cassette became dominant as a result of Philips decision to license the format free of charge, Philips also released the Norelco Carry-Corder 150 recorder/player in the US in November 1964. By 1966 over 250,000 recorders had been sold in the US alone, by 1968,85 manufacturers had sold over 2.4 million players. By the end of the 1960s, the business was worth an estimated 150 million dollars. In the early years sound quality was mediocre, but it improved dramatically by the early 1970s when it caught up with the quality of 8-track tape, the Compact Cassette went on to become a popular alternative to the 12-inch vinyl LP during the late 1970s. The mass production of blank Compact Cassettes began in 1964 in Hanover, prerecorded music cassettes were launched in Europe in late 1965
8.
Disk II
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The Disk II Floppy Disk Subsystem, often rendered as Disk ][, is a 5¼-inch floppy disk drive designed by Steve Wozniak and manufactured by Apple Computer. It went on sale in June 1978 at a price of US$495 for pre-order, it was later sold for $595 including the controller card. The Disk II was designed specifically for use with the Apple II personal computer family to replace the slower cassette tape storage and these floppy drives cannot be used with any Macintosh computer without an Apple IIe Card as doing so will damage the drive or the controller. Most DuoDisk drives, the Disk IIc, the UniDisk 5.25, the only 5.25 drive Apple sold aside from the Disk II family was a 360k MFM unit made to allow Mac IIs and SEs to read PC floppy disks. Apple did not originally offer a drive for the Apple II. Wozniak knew nothing about disk controllers, but while at Hewlett-Packard had designed a simple, Wozniak began studying existing floppy controllers, including North Star and IBM models. Standard floppy controller boards were large devices that used dozens of TTL chips, in addition to being expensive, they were also much too big to fit into the Apple IIs small case. Initially, Wozniak attempted to develop an FM-type controller with a chip count and by making improvements to the FM encoding scheme. This allowed still more storage, up to 13 sectors per track, Wozniak called the resultant Disk II system my most incredible experience at Apple and the finest job I did, and credited it and VisiCalc with the Apple IIs success. For a while, the direct competitor in the microcomputer industry was the TRS-80 Model I. Both the Atari 8-bit and Commodore 64s disk drives throughputs were much slower than the Disk IIs 15K bytes per second, however, the advantage of Wozniaks design was somewhat nullified when the cost of double-density MFM controllers dropped only a year after the Disk IIs introduction. The Apple IIs lack of a drive was a glaring weakness in what was otherwise intended to be a polished. Speaking later, Osborne I designer Lee Felsenstein stated, The difference between cassette and disk systems was the difference between hobbyist devices and a computer and you couldnt have expected, say, VisiCalc, to run on a cassette system. Recognizing that the II needed a drive to be taken seriously, Apple set out to develop a disk drive. Wozniak spent the 1977 Christmas holidays adapting his controller design, which reduced the number of chips used by a factor of 10 compared to existing controllers, still lacking a DOS, and with Wozniak inexperienced in operating system design, Jobs approached Shepardson Microsystems with the project. On April 10,1978 Apple signed a contract for $13,000 with Sheperdson to develop the DOS, the initial Disk II drives were modifications of the Shugart SA-400, which was the first commercially available 5.25 diskette drive. Apple purchased only the drive mechanisms without the standard SA-400 controller board, replaced it with Wozniaks board design. Early production at Apple was handled by two people, and they assembled 30 drives a day, by 1982, Apple switched to Alps drives for cost reasons
9.
NTSC
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The first NTSC standard was developed in 1941 and had no provision for color. In 1953 a second NTSC standard was adopted, which allowed for television broadcasting which was compatible with the existing stock of black-and-white receivers. NTSC was the first widely adopted broadcast color system and remained dominant until 1997, North America, parts of Central America, and South Korea are adopting or have adopted the ATSC standards, while other countries are adopting or have adopted other standards instead of ATSC. After nearly 70 years, the majority of over-the-air NTSC transmissions in the United States ceased on January 1,2010, the majority of NTSC transmissions ended in Japan on July 24,2011, with the Japanese prefectures of Iwate, Miyagi, and Fukushima ending the next year. In March 1941, the committee issued a standard for black-and-white television that built upon a 1936 recommendation made by the Radio Manufacturers Association. Technical advancements of the side band technique allowed for the opportunity to increase the image resolution. The NTSC selected 525 scan lines as a compromise between RCAs 441-scan line standard and Philcos and DuMonts desire to increase the number of lines to between 605 and 800. The standard recommended a frame rate of 30 frames per second, other standards in the final recommendation were an aspect ratio of 4,3, and frequency modulation for the sound signal. In January 1950, the committee was reconstituted to standardize color television, in December 1953, it unanimously approved what is now called the NTSC color television standard. The compatible color standard retained full backward compatibility with existing black-and-white television sets, Color information was added to the black-and-white image by introducing a color subcarrier of precisely 315/88 MHz. These changes amounted to 0.1 percent and were tolerated by existing television receivers. The FCC had briefly approved a different color standard, starting in October 1950. However, this standard was incompatible with black-and-white broadcasts and it used a rotating color wheel, reduced the number of scan lines from 525 to 405, and increased the field rate from 60 to 144, but had an effective frame rate of only 24 frames per second. CBS rescinded its system in March 1953, and the FCC replaced it on December 17,1953, with the NTSC color standard, later that year, the improved TK-41 became the standard camera used throughout much of the 1960s. The NTSC standard has been adopted by countries, including most of the Americas. With the advent of television, analog broadcasts are being phased out. Most US NTSC broadcasters were required by the FCC to shut down their analog transmitters in 2009, low-power stations, Class A stations and translators were required to shut down by 2015. NTSC color encoding is used with the System M television signal, each frame is composed of two fields, each consisting of 262.5 scan lines, for a total of 525 scan lines
10.
RCA connector
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An RCA connector, sometimes called a phono connector or Cinch connector, is a type of electrical connector commonly used to carry audio and video signals. The connectors are sometimes casually referred to as A/V jacks. The name RCA derives from the Radio Corporation of America, which introduced the design by the early 1940s for internal connection of the pickup to the chassis in home radio-phonograph consoles. It was originally a low-cost, simple design, intended only for mating, refinement came with later designs, although they remained compatible. However, quarter-inch phone connectors are common in professional audio. The connections plug is called an RCA plug or phono plug, the name phono plug is sometimes confused with a phone plug which may refer to a quarter-inch phone plug – Tip/Sleeve or Tip/Ring/Sleeve connector – or to a 4P4C connector used for a telephone. In the most normal use, cables have a plug on each end, consisting of a central male connector. The ring is often segmented for flexibility, devices mount the socket, consisting of a central hole with a ring of metal around it. The ring is smaller in diameter and longer than the ring on the plug. The jack has an area between the outer and inner rings which is filled with an insulator, typically plastic. Its use as a connector for video signals is extremely common. RCA connectors and cable are commonly used to carry S/PDIF-formatted digital audio. Connections are made by pushing the cables plug into the jack on the device. Continuous noise can occur if the plug partially falls out of the jack, breaking ground connection, some variants of the plug, especially cheaper versions, also give very poor grip and contact between the ground sheaths due to their lack of flexibility. They are often color-coded, yellow for composite video, red for the audio channel. This trio of jacks can be found on the back of almost all audio, one or more sets are often found on TV sets to facilitate connection of camcorders, other portable video sources and video game consoles. Varying cable quality means that a cheap line-level audio cable might not successfully transfer component video, cables should meet the S/PDIF specification as defined by the international standard IEC 60958-3 for assured performance. The male plug has a pin which is 3.175 mm in diameter
11.
Phone connector (audio)
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A phone connector, also known as phone jack, audio jack, headphone jack or jack plug, is a common family of electrical connector typically used for analog signals, primarily audio. It is cylindrical in shape, typically two, three, four and, recently, five contacts. Three-contact versions are known as TRS connectors, where T stands for tip, R stands for ring, similarly, two-, four- and five- contact versions are called TS, TRRS and TRRRS connectors respectively. The phone connector was invented for use in telephone switchboards in the 19th century and is widely used. In its original configuration, the diameter of the sleeve conductor is 1⁄4 inch. The mini connector has a diameter of 3.5 mm, specific models are termed stereo plug, mini-stereo, mini jack, headphone jack and microphone jack, or are referred to by size, i. e.3. 5mm or 6. 35mm. In the UK, the terms jack plug and jack socket are commonly used for the male and female phone connectors. In the US, an electrical connector is called a jack. Phone plugs and jacks are not to be confused with the similar terms phono plug and phono jack which refer to RCA connectors common in consumer hi-fi, the 3.5 mm connector is, however, sometimes—but counter to the connector manufacturers nomenclature—referred to as mini phono. Modern phone connectors are available in three standard sizes, the original 1⁄4 in version dates from 1878, when it was used for manual telephone exchanges, making it the oldest electrical connector standard still in use. The 3.5 mm or miniature and 2.5 mm or sub-miniature sizes were originally designed as two-conductor connectors for earpieces on transistor radios since the 1950s, the standard still used today. The 3.5 mm connector, which is the most commonly used in application today, was popularized by the Sony EFM-117J radio which was released in 1964. It became very popular with its application on the Walkman in 1979, the 3.5 mm and 2.5 mm sizes are sometimes referred to as 1⁄8 in and 3⁄32 in respectively in the United States, though those dimensions are only approximations. All three sizes are now available in two-conductor and three-conductor versions. Four- and five-conductor versions of the 3.5 mm plug are used for certain applications, a four-conductor version is often used in compact camcorders and portable media players, and sometimes also in laptop computers and smartphones, providing stereo sound plus a video signal. Proprietary interfaces using both four- and five-conductor versions exist, where the conductors are used to supply power for accessories. The four-conductor 3.5 mm plug is used as a connector on handheld amateur radio transceivers from Yaesu. It is also used in some amps like the LH Labs Geek Out V2+ for a balanced output, the most common arrangement remains to have the male plug on the cable and the female socket mounted in a piece of equipment, the original intention of the design
12.
Paddle (game controller)
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A paddle is a game controller with a round wheel and one or more fire buttons, where the wheel is typically used to control movement of the player object along one axis of the video screen. A paddle controller rotates through an arc, it has a stop at each end. The paddle wheel is usually coupled to a potentiometer, so as to generate an output voltage level varying with the wheels angle relative to a fixed reference position. A paddle is thus an absolute position controller and that is, without any previous knowledge, the sensor can be read and the result directly indicates the position of the paddle knob. This is in contrast to a rotary encoder-based device or spinner, paddles first appeared in video arcade games with Atari Inc. s Pong in 1972, while the first console to use paddles was Magnavoxs Odyssey that same year. The Apple II shipped with paddles until 1980, the Atari 2600 used paddles for several of its games, as did early home computers such as the Commodore VIC-20. Any recent game that has paddle-type control uses a quadrature encoder instead, the reason for the name paddle for this type of game controller is that the first game that used it, Pong, was a video game simulation of table tennis, whose racquets are commonly called paddles. Even though the simulated paddles appeared on-screen, it was the controllers used to move the line segments that actually came to bear the name. Some famous video games using paddles are Pong, Breakout, on the Atari 2600, the paddle controllers look very similar to the driving controllers. The driving controllers for Atari consoles operated in the way, although they did not have a wheel. In comparison to the controllers, paddle controllers rotate just under one full rotation before hitting a hard stop. They also come in pairs that plug into a single port, finally, they have a picture of a tennis racquet and the word paddle on it, as opposed to a racing car and the word driving. Because two controllers connect to each port and the 2600 has two ports, four players simultaneously can play in games that support it. The Atari paddles are also compatible with the Atari 800 home computer and this would allow eight paddles in simultaneous play. Super Breakout is one example that supported up to 8 players, Atari also offered driving controllers for use with games like Indy 500, which requires wheels that can spin around continuously in one direction. Driving controllers have a picture of a car and the driving on it. The driving controller is not compatible with paddle games, like a mechanical computer mouse, the driving controller is a quadrature encoder-based device and thus only sensed relative position, not absolute position. This controller is functionally identical to the controller used in Ataris Tempest arcade game
13.
Parallel port
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A parallel port is a type of interface found on computers for connecting peripherals. The name refers to the way the data is sent, parallel ports send multiple bits of data at once, in parallel communication, as opposed to serial interfaces that send bits one at a time. To do this, parallel ports require multiple data lines in their cables and port connectors, there are many types of parallel ports, but the term has become most closely associated with the printer port or Centronics port found on most personal computers from the 1970s through the 2000s. Today, the port interface is virtually non-existent because of the rise of Universal Serial Bus devices, along with network printing using Ethernet. The parallel port interface was originally known as the Parallel Printer Adapter on IBM PC-compatible computers and it was primarily designed to operate printers that used IBMs 8-bit extended ASCII character set to print text, but could also be used to adapt other peripherals. Graphical printers, along with a host of other devices, have designed to communicate with the system. An Wang, Robert Howard and Prentice Robinson began development of a low-cost printer at Centronics, the printer used the dot matrix printing principle, with a print head consisting of a vertical row of seven metal pins connected to solenoids. When power was applied to the solenoids, the pin was pulled forward to strike the paper and leave a dot. On their original design, a typical glyph was printed as a matrix seven high and five wide, while the A models used a print head with 9 pins and this left the problem of sending the ASCII data to the printer. While a serial port does so with the minimum of pins and wires, it requires the device to buffer up the data as it arrives bit by bit, a parallel port makes this simpler, the entire ASCII value is presented on the pins in complete form. In addition to the seven pins, the system also needed various control pins as well as electrical grounds. Wang happened to have a stock of 20,000 Amphenol 36-pin micro ribbon connectors that were originally used for one of their early calculators. The interface only required 21 of these pins, the rest were grounded or not connected, the connector has become so closely associated with Centronics that it is now popularly known as the Centronics connector. The Centronics Model 101 printer, featuring this connector, was released in 1970, the host sent ASCII characters to the printer using 7 of 8 data pins, pulling them high to +5V to represent a 1. When the data was ready, the host pulled the STROBE pin low, the printer responded by pulling the BUSY line high, printing the character, and then returning BUSY to low again. The host could send another character. Control characters in the data caused other actions, like the CR or EOF, the host could also have the printer automatically start a new line by pulling the AUTOFEED line high, and keeping it there. The host had to watch the BUSY line to ensure it did not feed data to the printer too rapidly, especially given variable-time operations like a paper feed
14.
Serial port
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In computing, a serial port is a serial communication interface through which information transfers in or out one bit at a time. Throughout most of the history of computers, data was transferred through serial ports to devices such as modems, terminals. Modern computers without serial ports may require serial-to-USB converters to allow compatibility with RS-232 serial devices, serial ports are still used in applications such as industrial automation systems, scientific instruments, point of sale systems and some industrial and consumer products. Server computers may use a port as a control console for diagnostics. Network equipment often use serial console for configuration, serial ports are still used in these areas as they are simple, cheap and their console functions are highly standardized and widespread. A serial port requires very little supporting software from the host system, some computers, such as the IBM PC, use an integrated circuit called a UART. This IC converts characters to and from asynchronous serial form, implementing the timing and framing of data in hardware, very low-cost systems, such as some early home computers, would instead use the CPU to send the data through an output pin, using the bit-banging technique. Early home computers often had proprietary serial ports with pinouts and voltage levels incompatible with RS-232, low-cost processors now allow higher-speed, but more complex, serial communication standards such as USB and FireWire to replace RS-232. These make it possible to connect devices that would not have operated feasibly over slower serial connections, such as storage, sound. Many personal computer motherboards still have at least one serial port, small-form-factor systems and laptops may omit RS-232 connector ports to conserve space, but the electronics are still there. RS-232 has been standard for so long that the circuits needed to control a serial port became very cheap and often exist on a single chip, sometimes also with circuitry for a parallel port. The individual signals on a serial port are unidirectional and when connecting two devices the outputs of one device must be connected to the inputs of the other, devices are divided into two categories data terminal equipment and data circuit-terminating equipment. A line that is an output on a DTE device is an input on a DCE device and vice versa so a DCE device can be connected to a DTE device with a straight wired cable, conventionally, computers and terminals are DTE while modems and peripherals are DCE. If it is necessary to connect two DTE devices a cross-over null modem, in the form of either an adapter or a cable, generally, serial port connectors are gendered, only allowing connectors to mate with a connector of the opposite gender. With D-subminiature connectors, the male connectors have protruding pins, either type of connector can be mounted on equipment or a panel, or terminate a cable. Connectors mounted on DTE are likely to be male, and those mounted on DCE are likely to be female, however, this is far from universal, for instance, most serial printers have a female DB25 connector, but they are DTEs. The desire to supply serial interface cards with two ports required that IBM reduce the size of the connector to fit onto a single card back panel, a DE-9 connector also fits onto a card with a second DB-25 connector. Starting around the time of the introduction of the IBM PC-AT, serial ports were built with a 9-pin connector to save cost
15.
SCSI
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Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical and optical interfaces, SCSI is derived from SASI, the Shugart Associates System Interface, developed circa 1978 and publicly disclosed in 1981. A SASI controller provided a bridge between a hard disk drives low-level interface and a host computer, which needed to read blocks of data, SASI controller boards were typically the size of a hard disk drive and were usually physically mounted to the drives chassis. SASI, which was used in mini- and early microcomputers, defined the interface as using a 50-pin flat ribbon connector which was adopted as the first-generation SCSI connector. SASI is a fully compliant subset of SCSI-1 so that many, if not all, larry Boucher is considered to be the father of SASI and SCSI due to his pioneering work first at Shugart Associates and then at Adaptec. A number of such as NCR Corporation, Adaptec and Optimem were early supporters of the SCSI standard. The NCR facility in Wichita, Kansas is widely thought to have developed the industrys first SCSI chip, the small part in SCSI is historical, since the mid-1990s, SCSI has been available on even the largest of computer systems. Since its standardization in 1986, SCSI has been used in the Amiga, Atari, Apple Macintosh and Sun Microsystems computer lines. Apple started using Parallel ATA for its low-end machines with the Macintosh Quadra 630 in 1994, Apple dropped on-board SCSI completely with the Power Mac G3 in 1999, while still offering a PCI controller card as an option on up to the Power Macintosh G4 models. Sun switched its lower-end range to Serial ATA, Commodore included a SCSI interface on the Amiga 3000/3000T systems and it was an add-on to previous Amiga 500/2000 models. Starting with the Amiga 600/1200/4000 systems Commodore switched to the IDE interface, Atari included SCSI interface as standard in its Atari MEGA STE, Atari TT and Atari Falcon computer models. SCSI has never been popular in the low-priced IBM PC world, owing to the lower cost, however, SCSI drives and even SCSI RAIDs became common in PC workstations for video or audio production. Although much of the SCSI documentation talks about the parallel interface, Serial interfaces have a number of advantages over parallel SCSI, including higher data rates, simplified cabling, longer reach, and improved fault isolation. ISCSI preserves the basic SCSI paradigm, especially the command set, almost unchanged, through embedding of SCSI-3 over TCP/IP, SCSI is popular on high-performance workstations, servers, and storage appliances. Almost all RAID subsystems on servers have used some kind of SCSI hard disk drives for decades, moreover, SAS offers compatibility with SATA devices, creating a much broader range of options for RAID subsystems together with the existence of nearline SAS drives. SCSI is available in a variety of interfaces, the first was parallel SCSI, which uses a parallel bus design. Since 2005, SPI was gradually replaced by Serial Attached SCSI, ISCSI, for example, uses TCP/IP as a transport mechanism, which is most often transported over Gigabit Ethernet or faster network links. With the advent of SAS and SATA drives, provision for parallel SCSI on motherboards was discontinued, initially, the SCSI Parallel Interface was the only interface using the SCSI protocol
16.
Apple I
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Apple Computer 1, also known later as the Apple I, or Apple-1, is a desktop computer released by the Apple Computer Company in 1976. It was designed and hand-built by Steve Wozniak, Wozniaks friend Steve Jobs had the idea of selling the computer. It was demonstrated in July 1976 at the Homebrew Computer Club in Palo Alto, on March 5,1975, Steve Wozniak attended the first meeting of the Homebrew Computer Club in Gordon Frenchs garage. He was so inspired that he set to work on what would become the Apple I computer. After building it for himself and showing it at the Club, he and Steve Jobs gave out schematics for the computer to interested members and even helped some of them build. Then, Steve Jobs suggested that design and sell a single etched and silkscreened circuit board—just the bare board. To fund this venture, their first company, Jobs sold his van. Very soon after, Steve Jobs arranged to sell something like 100 completely built computers to the The Byte Shop at $500 each, to fulfill the $50,000 order, they obtained $20,000 in parts at 30 days net and delivered the finished product in 10 days. The Apple I went on sale in July 1976 at a price of US$666.66, because Wozniak liked repeating digits, the first unit produced was used in a high school math class, and donated to Liza Loops public access computer center. About 200 units were produced and all but 25 were sold during nine or ten months, the Apple Is built-in computer terminal circuitry was distinctive. All one needed was a keyboard and a television set. This made the Apple I an innovative machine for its day, in April 1977, the price was dropped to $475. It continued to be sold through August 1977, despite the introduction of the Apple II in April 1977, in October 1977, the Apple I was officially discontinued and removed from Apples price list. These recovered boards were destroyed by Apple, contributing to their rarity today. As of 2013, at least 63 Apple I computers have been confirmed to exist, only six have been verified to be in working condition. An Apple I reportedly sold for $50,000 USD at auction in 1999, in 2008, the website Vintage Computing and Gaming reported that Apple I owner Rick Conte was looking to sell his unit and was expecting a price in excess of $15,000 US. The site later reported Conte had donated the unit to the Maine Personal Computer Museum in 2009, a unit was sold in September 2009 for $17,480 on eBay. A unit belonging to early Apple Computer engineers Dick and Cliff Huston was sold on March 23,2010, in November 2010, an Apple I sold for £133,250 at Christies auction house in London
17.
Apple II Plus
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The Apple II Plus is the second model of the Apple II series of personal computers produced by Apple Computer, Inc. It was sold from June 1979 to December 1982, the Apple II Plus shipped with 16 KB,32 KB or 48 KB of main RAM, expandable to 64 KB by means of the Language Card, an expansion card that could be installed in the computers slot 0. For this reason, the extra RAM in the card was bank-switched over the machines built-in ROM. The Language Card was also required to use LOGO, Apple Pascal, the Apple II Plus included the Applesoft BASIC programming language in ROM. This Microsoft-authored dialect of BASIC, which was available as an upgrade, supported floating-point arithmetic. Like the Apple II, the Apple II Plus has no lowercase functionality, all letters from the keyboard are upper-case, there is no caps lock key, and there are no lowercase letters in the text-mode font stored in the computers ROM. To display lowercase letters, some run in the slower hi-res graphics mode and use a custom font. Other programs, primarily those where both capitalization and text movement were important, such as processors, use inverse text mode to represent text that would be uppercase when printed. The Videx Videoterm and its clones were especially popular. Compatible applications, including nearly all word processors, can detect whether the shift key was being pressed. Most applications that support lower-case letters can also use the ESC key as a substitute lowercase toggle if the modification is not installed, the Apple II Plus, like its predecessor the Apple II, had a repeat key built into its keyboard. The key was labeled REPT and was located just to the left of the RETURN key. The II Plus was the last Apple Computer to have this key, the II Plus had a plastic case with brass mesh running along the inside of the case. This mesh helped cut electromagnetic interference from being emitted from the computer, small grids of plastic pins, and sometimes Velcro® Brand Fasteners, were used to hold the cases top onto the computer. After the success of the first Apple II in the United States, Apple expanded its market to include Europe and the Far East in 1978, with the Apple II Europlus and the Apple II J-Plus. In these models, Apple made the hardware, software and firmware changes in order to comply with standards outside of the US. For the most part, the Apple II Europlus and J-Plus were identical to the Apple II Plus, production of the Europlus ended in 1983. The ITT2020 was an Apple II clone manufactured by ITT under license from Apple Computer, bell & Howell packaged the unit with optional back packs that offered various inputs and outputs for A/V equipment to easily interface with the II Plus
18.
Modem
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A modem is a network hardware device that modulates one or more carrier wave signals to encode digital information for transmission and demodulates signals to decode the transmitted information. The goal is attempting to produce a signal that can be transmitted easily, modems can be used with any means of transmitting analog signals, from light emitting diodes to radio. Modems are generally classified by the amount of data they can send in a given unit of time, usually expressed in bits per second. Modems can also be classified by their rate, measured in baud. The baud unit denotes symbols per second, or the number of times per second the modem sends a new signal. For example, the ITU V.21 standard used audio frequency shift keying with two frequencies, corresponding to two distinct symbols, to carry 300 bits per second using 300 baud. By contrast, the original ITU V.22 standard, which could transmit and receive four distinct symbols, news wire services in the 1920s used multiplex devices that satisfied the definition of a modem. However, the function was incidental to the multiplexing function, so they are not commonly included in the history of modems. S. SAGE modems were described by AT&Ts Bell Labs as conforming to their newly published Bell 101 dataset standard, while they ran on dedicated telephone lines, the devices at each end were no different from commercial acoustically coupled Bell 101,110 baud modems. The 201A and 201B Data-Phones were synchronous modems using two-bit-per-baud phase-shift keying, the famous Bell 103A dataset standard was also introduced by AT&T in 1962. It provided full-duplex service at 300 bit/s over normal phone lines, frequency-shift keying was used, with the call originator transmitting at 1,070 or 1,270 Hz and the answering modem transmitting at 2,025 or 2,225 Hz. The readily available 103A2 gave an important boost to the use of remote low-speed terminals such as the Teletype Model 33 ASR and KSR, AT&T reduced modem costs by introducing the originate-only 113D and the answer-only 113B/C modems. For many years, the Bell System maintained a monopoly on the use of its phone lines, however, the seminal Hush-a-Phone v. FCC case of 1956 concluded it was within the FCCs jurisdiction to regulate the operation of the Bell System. The FCC found that as long as a device was not electronically attached to the system and this led to a number of devices that mechanically connected to the phone through a standard handset. Since most handsets were supplied by Western Electric and thus of a standard design and this type of connection was used for many devices, such as answering machines. Acoustically coupled Bell 103A-compatible 300 bit/s modems were common during the 1970s, well-known models included the Novation CAT and the Anderson-Jacobson, the latter spun off from an in-house project at Stanford Research Institute. An even lower-cost option was the Pennywhistle modem, designed to be built using parts from electronics scrap, in December 1972, Vadic introduced the VA3400, notable for full-duplex operation at 1,200 bit/s over the phone network. Like the 103A, it used different frequency bands for transmit, in November 1976, AT&T introduced the 212A modem to compete with Vadic
19.
Home computer
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Home computers were a class of microcomputers entering the market in 1977, and becoming common during the 1980s. They were marketed to consumers as affordable and accessible computers that, however, a home computer often had better graphics and sound than contemporaneous business computers. Their most common uses were playing games, but they were also regularly used for word processing, doing homework. Home computers were usually not electronic kits, home computers were already manufactured in stylish metal or plastic enclosures. There were, however, commercial kits like the Sinclair ZX80 which were home and home-built computers since the purchaser could assemble the unit from a kit. For example, using a typical 1980s home computer as a home automation appliance would require the computer to be powered on at all times. Personal finance and database use required tedious data entry, by contrast, advertisements in the specialty computer press often simply listed specifications. Since most systems shipped with the BASIC programming language included on the system ROM, many users found programming to be a fun and rewarding experience, and an excellent introduction to the world of digital technology. Often the only difference may be the outlet through which they are purchased. Another change from the computer era is that the once-common endeavour of writing ones own software programs has almost vanished from home computer use. As early as 1965, some projects such as Jim Sutherlands ECHO IV explored the possible utility of a computer in the home. In 1969, the Honeywell Kitchen Computer was marketed as a gift item, and would have inaugurated the era of home computing. Computers became affordable for the public in the 1970s due to the mass production of the microprocessor starting in 1971. Early microcomputers such as the Altair 8800 had front-mounted switches and diagnostic lights to control and indicate internal system status, while two early home computers could be bought either in kit form or assembled, most home computers were only sold pre-assembled. The keyboard - a feature lacking on the Altair - was usually built into the case as the motherboard. Ports for plug-in peripheral devices such as a display, cassette tape recorders, joysticks. Usually the manufacturer would sell peripheral devices designed to be compatible with their computers as extra cost accessories, peripherals were not often interchangeable between different brands of home computer, or even between successive models of the same brand. To save the cost of a monitor, the home computer would often connect through an RF modulator to the family TV set
20.
Microcomputer
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A microcomputer is a small, relatively inexpensive computer with a microprocessor as its central processing unit. It includes a microprocessor, memory, and minimal input/output circuitry mounted on a printed circuit board. Microcomputers became popular in the 1970s and 1980s with the advent of increasingly powerful microprocessors, the predecessors to these computers, mainframes and minicomputers, were comparatively much larger and more expensive. Many microcomputers are also personal computers, the abbreviation micro was common during the 1970s and 1980s, but has now fallen out of common usage. The term microcomputer came into use after the introduction of the minicomputer. Most notably, the replaced the many separate components that made up the minicomputers CPU with one integrated microprocessor chip. The first microcomputer was the Japanese Sord Computer Corporations SMP80/08, which was followed by the SMP80/x, the French developers of the Micral N filed their patents with the term Micro-ordinateur, a literal equivalent of Microcomputer, to designate a solid state machine designed with a microprocessor. Use of audio cassettes for data storage replaced manual re-entry of a program every time the device was powered on. Large cheap arrays of silicon logic gates in the form of memory and EPROMs allowed utility programs. This replaced the slow, complex, and expensive teletypewriter that was common as an interface to minicomputers. All these improvements in cost and usability resulted in an explosion in their popularity during the late 1970s, a large number of computer makers packaged microcomputers for use in small business applications. This allowed businesses unable to afford leasing of a minicomputer or time-sharing service the opportunity to automate business functions, without hiring a full-time staff to operate the computers. A representative system of this era would have used an S100 bus, an 8-bit processor such as an Intel 8080 or Zilog Z80, the increasing availability and power of desktop computers for personal use attracted the attention of more software developers. In time, and as the industry matured, the market for personal computers standardized around IBM PC compatibles running DOS, everyday use of the expression microcomputer has declined significantly from the mid-1980s and has declined in commonplace usage since 2000. The term is most commonly associated with the first wave of all-in-one 8-bit home computers, although, or perhaps because, an increasingly diverse range of modern microprocessor-based devices fit the definition of microcomputer, they are no longer referred to as such in everyday speech. IBM first promoted the personal computer to differentiate themselves from other microcomputers, often called home computers. However, following its release, the IBM PC itself was widely imitated, the component parts were commonly available to producers and the BIOS was reverse engineered through cleanroom design techniques. IBM PC compatible clones became commonplace, and the personal computer
21.
Steve Wozniak
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Stephen Gary Steve Wozniak, nicknamed Woz, is an American inventor, electronics engineer, programmer, and technology entrepreneur who co-founded Apple Inc. He is known as a pioneer of the computer revolution of the 1970s and 1980s. Wozniak single-handedly developed the 1976 Apple I, which was the computer that launched Apple and he primarily designed the 1977 Apple II, while Jobs oversaw the development of its unusual case and Rod Holt developed the unique power supply. Steve Wozniak was born in San Jose, California, the son of Margaret Elaine and he is of Polish and Swiss-German ancestry. His father was from Bukovyna, Ukraine and his mother from German-Swiss background, the name on Wozniaks birth certificate is Stephan Gary Wozniak, but Steves mother said that she intended it to be spelled Stephen, and Steve is what he uses. Wozniak has been referred to frequently by the nickname Woz, The Wonderful Wizard of Woz, The Second Steve, or The Woz, the city of San Jose named a street Woz Way in his honour. In the early 1970s, Wozniak was also known as Berkeley Blue in the phone phreak community, in 1969, Wozniak returned to the Bay Area after being expelled from University of Colorado Boulder in his first year for hacking into the institutions computer system. During this time, Wozniak designed and built his Cream Soda computer with his friend Bill Fernandez and he later re-enrolled at De Anza College and transferred to University of California, Berkeley in 1971. Before focusing his attention on Apple, he was employed at Hewlett-Packard where he designed calculators and it was during this time that he befriended Steve Jobs. Steve Wozniak was introduced to Jobs by friend Bill Fernandez, who attended Homestead High School with Jobs in 1971, Jobs and Wozniak became friends when Jobs worked for the summer at Hewlett-Packard, where Wozniak too was employed, working on a mainframe computer. This was recounted by Wozniak in a 2007 interview with ABC News, of how, a friend said, you should meet Steve Jobs, because he likes electronics and he also plays pranks. In 1973, Jobs was working for arcade game company Atari, Inc. in Los Gatos and he was assigned to create a circuit board for the arcade video game Breakout. According to Atari co-founder Nolan Bushnell, Atari offered $100 for each chip that was eliminated in the machine, Jobs had little knowledge of circuit board design and made a deal with Wozniak to split the fee evenly between them if Wozniak could minimize the number of chips. Wozniak reduced the number of chips by 50, by using RAM for the brick representation, too complex to be fully comprehended at the time, the fact that this prototype also had no scoring or coin mechanisms meant Wozs prototype could not be used. Jobs was paid the full bonus regardless, Jobs told Wozniak that Atari gave them only $700 and that Wozniaks share was thus $350. Wozniak did not learn about the actual $5,000 bonus until ten years later, on June 29,1975 Wozniak tested his first working prototype, displaying a few letters and running sample programs. It was the first time in history that a character displayed on a TV screen was generated by a home computer. With the Apple I design, he and Jobs were largely working to impress members of the Palo Alto-based Homebrew Computer Club
22.
Steve Jobs
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Steven Paul Steve Jobs was an American entrepreneur, businessman, inventor, and industrial designer. He was the co-founder, chairman, and chief officer of Apple Inc. CEO and majority shareholder of Pixar, a member of The Walt Disney Companys board of directors following its acquisition of Pixar, and founder, chairman, Jobs and Apple co-founder Steve Wozniak are widely recognized as pioneers of the microcomputer revolution of the 1970s and 1980s. Jobs was born in San Francisco and adopted at birth, he was raised in the San Francisco Bay Area during the 1960s, Jobs briefly attended Reed College in 1972 before dropping out. He then decided to travel through India in 1974 seeking enlightenment, Jobss declassified FBI report stated that an acquaintance knew that Jobs had used the illegal drugs marijuana and LSD while he was in college. Jobs once told a reporter that taking LSD was one of the two or three most important things he did in his life, Jobs and Wozniak co-founded Apple in 1976 to sell Wozniaks Apple I personal computer. The visionaries gained fame and wealth a year later for the Apple II, in 1979, after a tour of PARC, Jobs saw the commercial potential of the Xerox Alto, which was mouse-driven and had a graphical user interface. This led to development of the unsuccessful Apple Lisa in 1983, following a long power struggle, Jobs was forced out of Apple in 1985. In addition, Jobs helped to initiate the development of the effects industry when he funded the spinout of the computer graphics division of George Lucass Lucasfilm in 1986. The new company, Pixar, would produce the first fully computer-animated film. In 1997, Apple merged with NeXT, within a few months of the merger, Jobs became CEO of his former company, reviving Apple at the verge of bankruptcy. Mac OS was also revamped into OS X, based on NeXTs NeXTSTEP platform, Jobs was diagnosed with a pancreatic neuroendocrine tumor in 2003 and died on October 5,2011 of respiratory arrest related to the tumor. Steve Jobss biological father, Abdulfattah John Jandali, was born into a Muslim household and grew up in Homs, Jandali is the son of a self-made millionaire who did not go to college and a mother who was a traditional housewife. While an undergraduate at the American University of Beirut, he was a student activist, although Jandali initially wanted to study law, he eventually decided to study economics and political science. He pursued a PhD in the subject at the University of Wisconsin, where he met Joanne Carole Schieble, a Catholic of Swiss and German descent. As a doctoral candidate, Jandali was an assistant for a course Schieble was taking. Mona Simpson, notes that her grandparents were not happy that their daughter was dating Jandali. But there are a lot of Arabs in Michigan and Wisconsin, Walter Isaacson, Steve Jobss official biographer, additionally states that Schiebles father threatened to cut Joanne off completely if she continued the relationship
23.
Switched-mode power supply
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A switched-mode power supply is an electronic power supply that incorporates a switching regulator to convert electrical power efficiently. Like other power supplies, an SMPS transfers power from a DC or AC source, to DC loads, such as a computer, while converting voltage. Ideally, a power supply dissipates no power. Voltage regulation is achieved by varying the ratio of on-to-off time, in contrast, a linear power supply regulates the output voltage by continually dissipating power in the pass transistor. This higher power efficiency is an important advantage of a switched-mode power supply. Switched-mode power supplies may also be smaller and lighter than a linear supply due to the smaller transformer size. Switching regulators are used as replacements for linear regulators when higher efficiency and they are, however, more complicated, their switching currents can cause electrical noise problems if not carefully suppressed, and simple designs may have a poor power factor. 1836 Induction coils use switches to generate high voltages,1910 An inductive discharge ignition system invented by Charles F. Kettering and his company Dayton Engineering Laboratories Company goes into production for Cadillac. The Kettering ignition system is a version of a flyback boost converter. Variations of this system were used in all non-diesel internal combustion engines until the 1960s when it was displaced with capacitive discharge ignition systems. 1926 On 23 June, British inventor Philip Ray Coursey applies for a patent in his country and United States, the patent mentions high frequency welding and furnaces, among other uses. Ca 1936 Car radios used electromechanical vibrators to transform the 6 V battery supply to a suitable B+ voltage for the vacuum tubes,1959 Transistor oscillation and rectifying converter power supply system U. S. 1972 HP-35, Hewlett-Packards first pocket calculator, is introduced with transistor switching power supply for light-emitting diodes, clocks, timing, ROM,1973 Xerox uses switching power supplies in the Alto minicomputer 1977 Apple II is designed with a switching mode power supply. Rod Holt was brought in as engineer and there were several flaws in Apple II that were never publicized. One thing Holt has to his credit is that he created the power supply that allowed us to do a very lightweight computer. 1980 The HP8662A10 kHz –1.28 GHz synthesized signal generator went with a switched mode power supply, a linear regulator provides the desired output voltage by dissipating excess power in ohmic losses. Ideal switching elements have no resistance when closed and carry no current when open and this is because the inductor responds to changes in current by inducing its own voltage to counter the change in current, and this voltage adds to the source voltage while the switch is open. This boost converter acts like a transformer for DC signals
24.
Apple IIe
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The Apple IIe is the third model in the Apple II series of personal computers produced by Apple Computer. The e in the stands for enhanced, referring to the fact that several popular features were now built-in that were available only as upgrades or add-ons in earlier models. It also improved upon expandability and added a few new features, the Apple IIe has the distinction of being the longest-lived computer in Apples history, having been manufactured and sold for nearly 11 years with relatively few changes. Management believed that once the Apple III was out, the Apple II would stop selling in six months, by the time IBM released the rival IBM PC in 1981, the Apple IIs technology was already four years old. After the Apple III initially struggled, management decided in 1981 that the continuation of the Apple II was in the companys best interest. After 3 1⁄2 years of the Apple II Plus, essentially at a standstill, the Apple IIe was released in January 1983, the successor to the Apple II Plus. The Apple IIe was the first Apple computer with a custom ASIC chip, which reduced much of the old discrete IC-based circuitry to a chip, reducing cost. Some of the features of the Apple III were borrowed in the design of the Apple IIe. The culmination of these led to increased sales and greater market share of home, education. One of the most notable improvements of the Apple IIe is the addition of a full ASCII character set, the most important addition is the ability to input and display lower-case letters. Other keyboard improvements include four-way cursor control and standard editing keys, the auto-repeat function is now automatic, no longer requiring the REPT key found on the previous models keyboard. As time progressed, even more memory could be added through third-party cards using the same bank-switching slot or, alternatively, a new ROM diagnostic routine could be invoked to test the motherboard for faults and also test its main bank of memory. The Apple IIe lowered production costs and improved reliability by merging the function of several off-the-shelf ICs into single custom chips, the IIe also switched to using newer single-voltage 4164 DRAM chips instead of the unreliable triple-voltage 4116 DRAM in the II/II+. For this reason the design is much cleaner and runs cooler as well. Also added was a backport-accessible DE-9 joystick connector, making it far easier for users to add and remove game, also improved were port openings for expansion cards. Later-production IIe models had the RAM soldered to the board rather than socketed. Despite the changes the IIe maintains a degree of backwards compatibility with the previous models. Apple provided technical information on the IIe to hundreds of developers before its release, and claimed that, as a result,85 to 90% of Apple II software worked with it
25.
Commodore PET
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The Commodore PET is a line of home/personal computers produced starting in 1977 by Commodore International. The first model, which was named the PET2001, was the personal computer ever made available to retail consumers, after the Apple II. In the 1970s Commodore was one of many companies selling calculators designed around Dallas-based Texas Instruments chips. Commodore responded to this by searching for a set they could purchase outright. At Commodore, Peddle convinced Jack Tramiel that calculators were a dead-end, in September 1976 Peddle got a demonstration of Jobs and Wozniaks Apple II prototype, when Jobs was offering to sell it to Commodore, but Commodore considered Jobs offer too expensive. Tramiel demanded that Peddle, Bill Seiler, and John Feagans create a computer in time for the June 1977 Consumer Electronics Show, tramiels son, Leonard, helped design the PETSCII graphic characters and acted as quality control. The result was the first all-in-one home computer, the PET and its 6502 processor controlled the screen, keyboard, cassette tape recorders and any peripherals connected to one of the computers several expansion ports. The machine also included a built-in Datasette for data storage located on the front of the case, the data transfer rate to cassette tape was 1500 baud, but the data was recorded to tape twice for safety, giving an effective rate of 750 baud. The PET2001 was announced at the Winter CES in January 1977, however, the PET was back-ordered for months and to ease deliveries, early in 1978 Commodore decided to cancel the 4 kB version. However, this took six months to finally happen, during which time Microsoft lost money. At the end of the year, the company was saved by Apples decision to license Microsoft BASIC for the Apple II line. The key tops also tended to rub off easily, reliability was fairly poor, although that was not atypical of many early microcomputers. Because of the keyboard on the PET, external replacement ones quickly appeared. On the other hand, Commodore was a year behind Apple, in 1979, Commodore replaced the original PET2001 with an improved model known as the 2001-N. The new machine used a standard green-phosphor monitor in place of the blue in the original 2001. It now had a conventional, full-sized keyboard and no longer sported the built-in cassette recorder, the kernel ROM was upgraded to add support for Commodores newly introduced disk drive line. It was offered in 8kB, 16kB, or 32kB models as the 2001-N8, 2001-N16, the 2001-N switched to using conventional DRAM instead of the 6550 SRAM in the original model. PET 2001-8Ns had eight 2108 DRAMs and 2001-16Ns used sixteen 2108s, the PET4016 used eight 4116 chips
26.
TRS-80
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The TRS-80 Micro Computer System is a desktop microcomputer launched in 1977 and sold by Tandy Corporation through their Radio Shack stores. The name is an abbreviation of Tandy/Radio Shack, Z-80 microprocessor and it was one of the earliest mass-produced personal computers. By 1979, the TRS-80 had the largest selection of software in the microcomputer market, until 1982, the TRS-80 was the best-selling PC line, outselling the Apple II series by a factor of 5 according to one analysis. In mid-1980, the broadly compatible TRS-80 Model III was released, the Model I was discontinued shortly after, primarily due to stricter FCC regulations on the radio-frequency interference it caused in surrounding electronics. In 1983, the Model III was in turn succeeded by the compatible Model 4, in the mid-1970s, Tandy Corporations Radio Shack division was a successful American chain of more than 3,000 electronics stores. After buyer Don French purchased a MITS Altair kit computer, he began designing his own, although the design did not impress Roach, the idea of selling a microcomputer did. When the two men visited National Semiconductor in California in mid-1976, Steve Leiningers expertise on the SC/MP microprocessor impressed them, the company envisioned a kit, but Leininger persuaded the others that because too many people cant solder, a preassembled computer would be better. Many opposed the project, one executive told French, Dont waste my time—we cant sell computers, as the popularity of CB radio—at one point comprising more than 20% of Radio Shacks sales—declined, however, the company sought new products. In February 1977 they showed their prototype, running a simple tax-accounting program, to Charles Tandy, after the demonstration Tandy revealed that he had already leaked the computers existence to the press, so the project was approved. MITS sold 1,000 Altairs in February 1975, and was selling 10,000 a year. Leininger and French suggested that Radio Shack could sell 50,000 computers, Roach persuaded Tandy to agree to build 3, 500—the number of Radio Shack stores—so that each store could use a computer for inventory purposes if they did not sell. Having spent less than US$150,000 on development, Radio Shack announced the TRS-80 at a New York City press conference on August 3,1977. It cost US$399, or US$599 with a 12 monitor and a Radio Shack tape recorder as datacassette storage, the company hoped that the new computer would help Radio Shack sell higher-priced products, and improve its schlocky image among customers. Despite the internal skepticism, Radio Shack aggressively entered the market, the company advertised The $599 personal computer as the most important, useful, exciting, electronic product of our time. The company announced plans to be selling by Christmas a range of peripherals and software for the TRS-80, began shipping computers by September, the first units, ordered unseen, were delivered in November 1977, and rolled out to the stores the third week of December. The line won popularity with hobbyists, home users, and small-businesses, Tandy Corporations leading position in what Byte Magazine called the 1977 Trinity had much to do with Tandys retailing the computer through more than 3,000 of its Radio Shack storefronts. Notable features of the original TRS-80 included its full-stroke QWERTY keyboard, small size, its floating-point BASIC programming language, a monitor. The pre-release price was US$500 and a US$50 deposit was required, by 1980 InfoWorld described Radio Shack as the dominant supplier of small computers
27.
Byte (magazine)
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Byte magazine was an American microcomputer magazine, influential in the late 1970s and throughout the 1980s because of its wide-ranging editorial coverage. Coverage was in-depth with much detail, rather than user-oriented. Print publication ceased in 1998 and online publication in 2013, Byte started in 1975, shortly after the first personal computers appeared as kits advertised in the back of electronics magazines. Byte was published monthly, with a yearly subscription price of $10. In 1975 Wayne Green was the editor and publisher of 73 and his ex-wife, on May 25th we made a deal with the publisher of a small computer hobby magazine to take over as editor of a new publication which would start in August. Carl Helmers published a series of six articles in 1974 that detailed the design and construction of his Experimenters Computer System, in January 1975 this became the monthly ECS magazine with 400 subscribers. The last issue was published on May 12,1975 and in June the subscribers were mailed a notice announcing Byte magazine, carl wrote to another hobbyist newsletter, Micro-8 Computer User Group Newsletter, and described his new job as editor of Byte magazine. I got a note in the mail about two weeks ago from Wayne Green, publisher of 73 Magazine essentially saying hello and why dont you come up, the net result of a follow up is the decision to create BYTE magazine using the facilities of Green Publishing Inc. I will end up with the focus for the magazine. Virginia Londner Green had returned to 73 in the December 1974 issue, the first five issues of Byte were published by Green Publishing and the name was changed to Byte Publications starting with the February 1976 issue. Carl Helmers was a co-owner of Byte Publications, the first four issues were produced in the offices of 73 and Wayne Green was listed as the publisher. One day in November 1975 Wayne came to work and found that the Byte magazine staff had moved out, the February 1976 issue of Byte has a short story about the move. After a start which reads like a light opera with an episode or two reminiscent of the Keystone Cops, Byte magazine finally has moved into separate offices of its own. Wayne Green was not happy about losing Byte magazine so he was going to start a new one called Kilobyte, Byte quickly trademarked KILOBYTE as a cartoon series in Byte magazine. The new magazine was called Kilobaud, there was competition and animosity between Byte Publications and 73 Inc. but both remained in the small town of Peterborough, New Hampshire. Byte was able to attract advertising and articles from many well-knowns, soon-to-be-well-knowns, articles in the first issue included Which Microprocessor For You. by Hal Chamberlin, Write Your Own Assembler by Dan Fylstra and Serial Interface by Don Lancaster. Advertisements from Godbout, MITS, Processor Technology, SCELBI, and Sphere appear, early articles in Byte were do-it-yourself electronic or software projects to improve small computers. A continuing feature was Ciarcias Circuit Cellar, a column in which electronic engineer Steve Ciarcia described small projects to modify or attach to a computer, Byte ran Microsofts first advertisement, as Micro-Soft, to sell a BASIC interpreter for 8080-based computers
28.
Silicon Valley
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Silicon Valley is a nickname for the southern portion of the San Francisco Bay Area, in the northern part of the U. S. state of California. The valley in its name refers to the Santa Clara Valley in Santa Clara County, which includes the city of San Jose and surrounding cities and towns, where the region has been traditionally centered. The region has expanded to include the half of the San Francisco Peninsula in San Mateo County. It was in the Valley that the integrated circuit, the microprocessor. As of 2013, the region employed about a quarter of an information technology workers. The term is now used as a synecdoche for the American high-technology economic sector. The first published use of Silicon Valley is credited to Don Hoefler, hostler used the phrase as the title of a series of articles in the weekly trade newspaper Electronic News. The series, entitled Silicon Valley in the USA, began in the papers January 11,1971, the term gained widespread use in the early 1980s, at the time of the introduction of the IBM PC and numerous related hardware and software products to the consumer market. The silicon part of the name refers to the concentration of companies involved in the making of semiconductors. These firms slowly replaced the orchards and the fruits which gave the area its initial nickname — the Valley of Hearts Delight, Stanford University leadership was especially important in the valleys early development. Together these elements formed the basis of its growth and success, the ship had been outfitted with a wireless telegraph transmitter by a local newspaper, so that they could prepare a celebration on the return of the American sailors. Local historian Clyde Arbuckle states in Clyde Arbuckles History of San Jose that California first heard the click of a key on September 11,1853. It marked completion of an enterprise begun by a couple of San Francisco Merchants Exchange members named George Sweeney and it was known as the Inner Station, the second, as the Outer Station. Both used their primitive mode of communication until Messrs, Sweeney and Baugh connected the Outer Station directly with the Merchantss Exchange by electric telegraph Wire. According to Arbuckle Sweeney and Baughs line was strictly an intra-city, San Francisco-based service, allen and C. Burnham led the way to build a line from San Francisco to Marysville via San Jose, Stockton, and Sacramento. Delays to construction occurred until September 1853, but, …San Jose became the first station on the line when the wire arrived here on October 15, the line was completed when Gambles northbound crew met a similar crew working southward from Marysville on October 24. The Bay Area had long been a site of United States Navy research. In 1909, Charles Herrold started the first radio station in the United States with regularly scheduled programming in San Jose
29.
Printed circuit board
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Components are generally soldered on the PCB. Advanced PCBs may contain components embedded in the substrate, PCBs can be single sided, double sided or multi-layer. Conductors on different layers are connected with vias, multi-layer PCBs allow for much higher component density. FR-4 glass epoxy is the primary insulating substrate, a basic building block of the PCB is an FR-4 panel with a thin layer of copper foil laminated to one or both sides. In multi-layer boards multiple layers of material are laminated together, printed circuit boards are used in all but the simplest electronic products. Alternatives to PCBs include wire wrap and point-to-point construction, PCBs require the additional design effort to lay out the circuit, but manufacturing and assembly can be automated. Manufacturing circuits with PCBs is cheaper and faster than other wiring methods as components are mounted and wired with one single part. A minimal PCB with a component used for easier prototyping is called a breakout board. When the board has no embedded components it is correctly called a printed wiring board or etched wiring board. However, the printed wiring board has fallen into disuse. A PCB populated with electronic components is called a printed circuit assembly, the IPC preferred term for assembled boards is circuit card assembly, and for assembled backplanes it is backplane assemblies. The term PCB is used both for bare and assembled boards. The world market for bare PCBs exceeded $60.2 billion in 2014, initially PCBs were designed manually by creating a photomask on a clear mylar sheet, usually at two or four times the true size. Starting from the diagram the component pin pads were laid out on the mylar. Rub-on dry transfers of common component footprints increased efficiency, traces were made with self-adhesive tape. Pre-printed non-reproducing grids on the mylar assisted in layout, to fabricate the board, the finished photomask was photolithographically reproduced onto a photoresist coating on the blank copper-clad boards. Modern PCBs are designed with dedicated software, generally in the following steps. Card dimensions and template are decided based on required circuitry and case of the PCB, the positions of the components and heat sinks are determined
30.
Republic of Ireland
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Ireland, also known as the Republic of Ireland, is a sovereign state in north-western Europe occupying about five-sixths of the island of Ireland. The capital and largest city is Dublin, which is located on the part of the island. The state shares its land border with Northern Ireland, a part of the United Kingdom. It is otherwise surrounded by the Atlantic Ocean, with the Celtic Sea to the south, Saint Georges Channel to the south-east, and it is a unitary, parliamentary republic. The head of government is the Taoiseach, who is elected by the Dáil and appointed by the President, the state was created as the Irish Free State in 1922 as a result of the Anglo-Irish Treaty. It was officially declared a republic in 1949, following the Republic of Ireland Act 1948, Ireland became a member of the United Nations in December 1955. It joined the European Economic Community, the predecessor of the European Union, after joining the EEC, Ireland enacted a series of liberal economic policies that resulted in rapid economic growth. The country achieved considerable prosperity between the years of 1995 and 2007, which known as the Celtic Tiger period. This was halted by a financial crisis that began in 2008. However, as the Irish economy was the fastest growing in the EU in 2015, Ireland is again quickly ascending league tables comparing wealth and prosperity internationally. For example, in 2015, Ireland was ranked as the joint sixth most developed country in the world by the United Nations Human Development Index and it also performs well in several national performance metrics, including freedom of the press, economic freedom and civil liberties. Ireland is a member of the European Union and is a member of the Council of Europe. The 1922 state, comprising 26 of the 32 counties of Ireland, was styled, the Constitution of Ireland, adopted in 1937, provides that the name of the State is Éire, or, in the English language, Ireland. Section 2 of the Republic of Ireland Act 1948 states, It is hereby declared that the description of the State shall be the Republic of Ireland. The 1948 Act does not name the state as Republic of Ireland, because to have done so would have put it in conflict with the Constitution. The government of the United Kingdom used the name Eire, and, from 1949, Republic of Ireland, for the state, as well as Ireland, Éire or the Republic of Ireland, the state is also referred to as the Republic, Southern Ireland or the South. In an Irish republican context it is referred to as the Free State or the 26 Counties. From the Act of Union on 1 January 1801, until 6 December 1922, during the Great Famine, from 1845 to 1849, the islands population of over 8 million fell by 30%
31.
Singapore
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Singapore, officially the Republic of Singapore, sometimes referred to as the Lion City or the Little Red Dot, is a sovereign city-state in Southeast Asia. It lies one degree north of the equator, at the tip of peninsular Malaysia. Singapores territory consists of one island along with 62 other islets. Since independence, extensive land reclamation has increased its size by 23%. During the Second World War, Singapore was occupied by Japan, after early years of turbulence, and despite lacking natural resources and a hinterland, the nation developed rapidly as an Asian Tiger economy, based on external trade and its workforce. Singapore is a global commerce, finance and transport hub, the country has also been identified as a tax haven. Singapore ranks 5th internationally and first in Asia on the UN Human Development Index and it is ranked highly in education, healthcare, life expectancy, quality of life, personal safety, and housing, but does not fare well on the Democracy index. Although income inequality is high, 90% of homes are owner-occupied, 38% of Singapores 5.6 million residents are permanent residents and other foreign nationals. There are four languages on the island, Malay, Mandarin, Tamil. English is its language, most Singaporeans are bilingual. Singapore is a multiparty parliamentary republic, with a Westminster system of unicameral parliamentary government. The Peoples Action Party has won every election since self-government in 1959, however, it is unlikely that lions ever lived on the island, Sang Nila Utama, the Srivijayan prince said to have founded and named the island Singapura, perhaps saw a Malayan tiger. There are however other suggestions for the origin of the name, the central island has also been called Pulau Ujong as far back as the third century CE, literally island at the end in Malay. In 1299, according to the Malay Annals, the Kingdom of Singapura was founded on the island by Sang Nila Utama and these Indianized Kingdoms, a term coined by George Cœdès were characterized by surprising resilience, political integrity and administrative stability. In 1613, Portuguese raiders burned down the settlement, which by then was part of the Johor Sultanate. The wider maritime region and much trade was under Dutch control for the following period, in 1824 the entire island, as well as the Temenggong, became a British possession after a further treaty with the Sultan. In 1826, Singapore became part of the Straits Settlements, under the jurisdiction of British India, prior to Raffles arrival, there were only about a thousand people living on the island, mostly indigenous Malays along with a handful of Chinese. By 1860 the population had swelled to over 80,000, many of these early immigrants came to work on the pepper and gambier plantations
32.
Hertz
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The hertz is the unit of frequency in the International System of Units and is defined as one cycle per second. It is named for Heinrich Rudolf Hertz, the first person to provide proof of the existence of electromagnetic waves. Hertz are commonly expressed in SI multiples kilohertz, megahertz, gigahertz, kilo means thousand, mega meaning million, giga meaning billion and tera for trillion. Some of the units most common uses are in the description of waves and musical tones, particularly those used in radio-. It is also used to describe the speeds at which computers, the hertz is equivalent to cycles per second, i. e. 1/second or s −1. In English, hertz is also used as the plural form, as an SI unit, Hz can be prefixed, commonly used multiples are kHz, MHz, GHz and THz. One hertz simply means one cycle per second,100 Hz means one hundred cycles per second, and so on. The unit may be applied to any periodic event—for example, a clock might be said to tick at 1 Hz, the rate of aperiodic or stochastic events occur is expressed in reciprocal second or inverse second in general or, the specific case of radioactive decay, becquerels. Whereas 1 Hz is 1 cycle per second,1 Bq is 1 aperiodic radionuclide event per second, the conversion between a frequency f measured in hertz and an angular velocity ω measured in radians per second is ω =2 π f and f = ω2 π. This SI unit is named after Heinrich Hertz, as with every International System of Units unit named for a person, the first letter of its symbol is upper case. Note that degree Celsius conforms to this rule because the d is lowercase. — Based on The International System of Units, the hertz is named after the German physicist Heinrich Hertz, who made important scientific contributions to the study of electromagnetism. The name was established by the International Electrotechnical Commission in 1930, the term cycles per second was largely replaced by hertz by the 1970s. One hobby magazine, Electronics Illustrated, declared their intention to stick with the traditional kc. Mc. etc. units, sound is a traveling longitudinal wave which is an oscillation of pressure. Humans perceive frequency of waves as pitch. Each musical note corresponds to a frequency which can be measured in hertz. An infants ear is able to perceive frequencies ranging from 20 Hz to 20,000 Hz, the range of ultrasound, infrasound and other physical vibrations such as molecular and atomic vibrations extends from a few femtoHz into the terahertz range and beyond. Electromagnetic radiation is described by its frequency—the number of oscillations of the perpendicular electric and magnetic fields per second—expressed in hertz. Radio frequency radiation is measured in kilohertz, megahertz, or gigahertz
33.
Random-access memory
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Random-access memory is a form of computer data storage which stores frequently used program instructions to increase the general speed of a system. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the location of data inside the memory. RAM contains multiplexing and demultiplexing circuitry, to connect the lines to the addressed storage for reading or writing the entry. Usually more than one bit of storage is accessed by the same address, in todays technology, random-access memory takes the form of integrated circuits. RAM is normally associated with types of memory, where stored information is lost if power is removed. Other types of non-volatile memories exist that allow access for read operations. These include most types of ROM and a type of memory called NOR-Flash. Integrated-circuit RAM chips came into the market in the early 1970s, with the first commercially available DRAM chip, early computers used relays, mechanical counters or delay lines for main memory functions. Ultrasonic delay lines could only reproduce data in the order it was written, drum memory could be expanded at relatively low cost but efficient retrieval of memory items required knowledge of the physical layout of the drum to optimize speed. Latches built out of vacuum tube triodes, and later, out of transistors, were used for smaller and faster memories such as registers. Such registers were relatively large and too costly to use for large amounts of data, the first practical form of random-access memory was the Williams tube starting in 1947. It stored data as electrically charged spots on the face of a cathode ray tube, since the electron beam of the CRT could read and write the spots on the tube in any order, memory was random access. The capacity of the Williams tube was a few hundred to around a thousand bits, but it was smaller, faster. In fact, rather than the Williams tube memory being designed for the SSEM, magnetic-core memory was invented in 1947 and developed up until the mid-1970s. It became a form of random-access memory, relying on an array of magnetized rings. By changing the sense of each rings magnetization, data could be stored with one bit stored per ring, since every ring had a combination of address wires to select and read or write it, access to any memory location in any sequence was possible. Magnetic core memory was the form of memory system until displaced by solid-state memory in integrated circuits. Data was stored in the capacitance of each transistor, and had to be periodically refreshed every few milliseconds before the charge could leak away
34.
Read-only memory
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Read-only memory is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM can only be modified slowly, with difficulty, or not at all, strictly, read-only memory refers to memory that is hard-wired, such as diode matrix and the later mask ROM, which cannot be changed after manufacture. Although discrete circuits can be altered in principle, integrated circuits cannot and that such memory can never be changed is a disadvantage in many applications, as bugs and security issues cannot be fixed, and new features cannot be added. More recently, ROM has come to include memory that is read-only in normal operation, the simplest type of solid-state ROM is as old as the semiconductor technology itself. Combinational logic gates can be joined manually to map n-bit address input onto arbitrary values of m-bit data output, with the invention of the integrated circuit came mask ROM. In mask ROM, the data is encoded in the circuit. This leads to a number of disadvantages, It is only economical to buy mask ROM in large quantities. The turnaround time between completing the design for a mask ROM and receiving the finished product is long, for the same reason, mask ROM is impractical for R&D work since designers frequently need to modify the contents of memory as they refine a design. If a product is shipped with faulty mask ROM, the way to fix it is to recall the product. Subsequent developments have addressed these shortcomings, PROM, invented in 1956, allowed users to program its contents exactly once by physically altering its structure with the application of high-voltage pulses. This addressed problems 1 and 2 above, since a company can order a large batch of fresh PROM chips. The 1971 invention of EPROM essentially solved problem 3, since EPROM can be reset to its unprogrammed state by exposure to strong ultraviolet light. All of these technologies improved the flexibility of ROM, but at a significant cost-per-chip, rewriteable technologies were envisioned as replacements for mask ROM. The most recent development is NAND flash, also invented at Toshiba, as of 2007, NAND has partially achieved this goal by offering throughput comparable to hard disks, higher tolerance of physical shock, extreme miniaturization, and much lower power consumption. Every stored-program computer may use a form of storage to store the initial program that runs when the computer is powered on or otherwise begins execution. Likewise, every non-trivial computer needs some form of memory to record changes in its state as it executes. Forms of read-only memory were employed as non-volatile storage for programs in most early stored-program computers, consequently, ROM could be implemented at a lower cost-per-bit than RAM for many years. Most home computers of the 1980s stored a BASIC interpreter or operating system in ROM as other forms of storage such as magnetic disk drives were too costly
35.
Composite video
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Composite video is an analog video transmission that carries standard definition video typically at 480i or 576i resolution. Video information is encoded on one channel, unlike the higher-quality S-video, Composite video is usually in standard formats such as NTSC, PAL, and SECAM and is often designated by the CVBS initialism, for color, video, blanking and sync, or simply as video. A composite video signal combines on one wire the video information required to recreate a picture, as well as line. The color video signal is a combination of the luminance of the picture, and a modulated subcarrier carries the chrominance or color information. Details of the process vary between the NTSC, PAL and SECAM systems. The burst signal is inverted in phase from the reference subcarrier, Composite video can easily be directed to any broadcast channel simply by modulating the proper RF carrier wave with it. On playback, these devices often give the user the option to output the signal or to modulate it onto a VHF or UHF frequency compatible with a TV tuner. In home applications, the video signal is typically connected using an RCA connector. It is often accompanied with red and white connectors for right, BNC connectors and higher quality coaxial cable are often used in professional television studios and post-production applications. BNC connectors were used for composite video connections on early home VCRs. The BNC connector, in turn post dated the PL-259 connector which featured on first generation VCRs. In Europe, SCART connections are used instead of RCA jacks, so where available, RGB is used instead of composite video with computers, video game consoles. Video cables are 75 ohm impedance, low in capacitance, typical values run from 52 pF/m for an HDPE-foamed dielectric precision video cable to 69 pF/m for a solid PE dielectric cable. Some devices that connect to a TV, such as VCRs, older video game consoles and home computers of the 1980s and this may then be converted to RF with an external box known as an RF modulator that generates the proper carrier. Sometimes this modulator was built into the product and sometimes it was a unit powered by the computer or with an independent power supply. In the United States, using an external RF modulator frees the manufacturer from obtaining FCC approval for each variation of a device, Video game consoles on the other hand were less of an issue with FCC approval because the circuitry was inexpensive enough to allow for channel 3/4 outputs. Modern day devices with analog outputs have typically omitted channel 3 and 4 outputs in favor of composite and S-video outputs as composite, in addition, many TV sets sold these days no longer have analog television tuners and cannot accept channel 3/4. The process of modulating RF with the video signal, and then demodulating the original signal again in the TV
36.
RF modulator
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An RF modulator is an electronic device whose input is a baseband signal which is used to modulate a radio frequency source. The aerial connector is standard on all TV sets, even very old ones, technically, RF modulation usually means combining the data with a carrier signal at a standardized frequency. Either amplitude or frequency modulation may be used, as required by the receiving equipment, in North America, RF modulators generally output on channel 3 or 4, which may be selectable, although the Atari consoles offer channels 2 and 3. In Europe standard modulators usually used channel 36 by default, but are usually tunable over part or all of the UHF band, modulating a TV signal with stereo sound is relatively complex, most low-cost home TV modulators produce a signal with monaural audio. Even some units that have two or more audio inputs simply combine the left and right audio channels into one mono audio signal, some used on very early home computers had no sound capability at all. Most cheaper modulators lack vestigial sideband filtering, RF modulators produce a relatively poor picture, as image quality is lost during both the modulation from the source device, and the demodulation in the television. RF modulators are commonly integrated into VCRs, in game consoles up to and including the fourth generation. Some systems were supplied with an external modulator unit that connected to both the system and to the jacks of a television. Multi-channel RF modulators are used in home audio/video distribution. These devices have multiple audio and video inputs and one RF output, audio/video outputs from source devices such as a DVD player, VCR, or DSS receiver are connected to the audio/video inputs on the modulator. The modulator is then programmed to broadcast the signals on a certain frequency and that RF broadcast is then received by the connected TV. When the TV is tuned to the channel, the video. RF modulation can become difficult in a CATV system, high pass, low pass, and notch filters must be used to block certain frequencies, or channels, so that the modulator can broadcast the audio/video signal of the source device on that channel. Professional modulators such as used in the CATV industry generally include vestigial sideband filtering which is generally absent on consumer grade modulators. Audio RF modulators are used in car audio to add devices like CD changers without requiring dashboard hardware upgrades. For example, a portable CD players headphone jack is connected to the modulator, car FM modulators suffer from loss of quality and interference issues. Later devices which would use these types of modulators would be iPods and similar portable media players
37.
Apple II graphics
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The Apple II graphics were composed of idiosyncratic modes and settings that could be exploited. This graphics system debuted on the original Apple II, continued with the Apple II Plus and was carried forward and expanded with the Apple IIe, Enhanced IIe, IIc, IIc Plus and IIGS. The graphic modes of the Apple II series were peculiar even by the standards of the late 1970s, one notable peculiarity of these modes is a direct result of Apple founder Steve Wozniaks chip-saving design. Many home computer systems of the time had architecture which assigned consecutive blocks of memory to non-consecutive rows on the screen in graphic modes, apples text and graphics modes are based on two different interleave factors of 8,1 and 64,1. A second peculiarity of Apple II graphics—the so-called color fringes—is yet another by-product of Wozniaks design, while these occur in all graphics modes, they play a crucial role in Hi-Resolution or Hi-Res mode. Reading a value from, or writing any value to, certain memory addresses controlled so called soft switches, the value read or written does not matter, what counts is the access itself. For example, one could switch from mixed graphics and text to a display by accessing location 0xC052. Then, to go back to mixed graphics and text, one would access 0xC053, all Apple II machines featured an RCA jack providing a rough NTSC, PAL, or SECAM composite video output. This enabled the computer to be connected to any composite video monitor conforming to the standard for which the machine was configured. In addition to the video output jack, the IIc, IIc Plus. In the IIc and IIc Plus, this connector was a video connector for adapters to digital RGB monitors. In the IIGS it was an output for an analog RGB monitor specially designed for the IIGS, numerous add-on video display cards were available for the Apple II series, such as the Apple 80-Column Text Card. There were PAL color cards which enabled color output on early PAL machines, some other cards simply added 80-column and lowercase display capabilities, while others allowed output to an IBM CGA monitor through a DE9 output jack. The Apple II video output is really a monochrome display based upon the bit patterns in the video memory and these pixels are combined in quadrature with the colorburst signal to be interpreted as color by a composite video display. High resolution provides two pixels per colorburst cycle, allowing for two colors if one pixel is on, black if no pixels are on, or white if both pixels are on. By shifting the alignment of the pixels to the colorburst signal by 90°, low resolution allows for four bits per cycle, but repeats the bit pattern several times per low resolution pixel. Double high resolution also displays four pixels per cycle, see the sections below for more details. The blocky, but fast and colorful Lo-Res graphics mode was 40 pixels wide and this mode could display either 40 rows of pixels with four lines of text at the bottom of the screen, or 48 rows of pixels with no text
38.
Dynamic random-access memory
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Dynamic random-access memory is a type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be charged or discharged, these two states are taken to represent the two values of a bit, conventionally called 0 and 1. Since even nonconducting transistors always leak a small amount, the capacitors will slowly discharge, because of this refresh requirement, it is a dynamic memory as opposed to static random-access memory and other static types of memory. Unlike flash memory, DRAM is volatile memory, since it loses its data quickly when power is removed, however, DRAM does exhibit limited data remanence. DRAM is widely used in digital electronics where low-cost and high-capacity memory is required, one of the largest applications for DRAM is the main memory in modern computers, and as the main memories of components used in these computers such as graphics cards. In contrast, SRAM, which is faster and more expensive than DRAM, is used where speed is of greater concern than cost. The advantage of DRAM is its simplicity, only one transistor. This allows DRAM to reach high densities. The transistors and capacitors used are small, billions can fit on a single memory chip. Due to the nature of its memory cells, DRAM consumes relatively large amounts of power. The cryptanalytic machine code-named Aquarius used at Bletchley Park during World War II incorporated a dynamic memory. Paper tape was read and the characters on it were remembered in a dynamic store, the store used a large bank of capacitors, which were either charged or not, a charged capacitor representing cross and an uncharged capacitor dot. Since the charge gradually leaked away, a pulse was applied to top up those still charged. In 1964, Arnold Farber and Eugene Schlig, working for IBM, created a hard-wired memory cell, using a transistor gate and they replaced the latch with two transistors and two resistors, a configuration that became known as the Farber-Schlig cell. In 1965, Benjamin Agusta and his team at IBM created a 16-bit silicon memory chip based on the Farber-Schlig cell, with 80 transistors,64 resistors, in 1966, DRAM was invented by Dr. Robert Dennard at the IBM Thomas J. Watson Research Center. He was granted U. S. patent number 3,387,286 in 1968, capacitors had been used for earlier memory schemes such as the drum of the Atanasoff–Berry Computer, the Williams tube and the Selectron tube. The Toshiba Toscal BC-1411 electronic calculator, which was introduced in November 1966, the first DRAM was introduced in 1969 by Advanced Memory system, Inc of Sunnyvale, CA </ref>. This 1000 bit chip was sold to Honeywell, Raytheon, Wang Computer among others, in 1969 Honeywell asked Intel to make a DRAM using a three-transistor cell that they had developed
39.
Analog-to-digital
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In electronics, an analog-to-digital converter is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a digital signal. Typically the digital output is a twos complement binary number that is proportional to the input, due to the complexity and the need for precisely matched components, all but the most specialized ADCs are implemented as integrated circuits. A digital-to-analog converter performs the function, it converts a digital signal into an analog signal. The conversion involves quantization of the input, so it necessarily introduces a small amount of error, furthermore, instead of continuously performing the conversion, an ADC does the conversion periodically, sampling the input. The result is a sequence of values that have been converted from a continuous-time and continuous-amplitude analog signal to a discrete-time. An ADC is defined by its bandwidth and its signal-to-noise ratio, the bandwidth of an ADC is characterized primarily by its sampling rate. The dynamic range of an ADC is influenced by many factors, including the resolution, linearity and accuracy, aliasing and jitter. The dynamic range of an ADC is often summarized in terms of its number of bits. An ideal ADC has an ENOB equal to its resolution, ADCs are chosen to match the bandwidth and required signal-to-noise ratio of the signal to be quantized. If an ADC operates at a rate greater than twice the bandwidth of the signal, then perfect reconstruction is possible given an ideal ADC. The presence of quantization error limits the range of even an ideal ADC. However, if the range of the ADC exceeds that of the input signal. The resolution of the converter indicates the number of values it can produce over the range of analog values. The resolution determines the magnitude of the error and therefore determines the maximum possible average signal to noise ratio for an ideal ADC without the use of oversampling. The values are stored electronically in binary form, so the resolution is usually expressed in bits. In consequence, the number of discrete values available, or levels, is assumed to be a power of two, for example, an ADC with a resolution of 8 bits can encode an analog input to one in 256 different levels, since 28 =256. The values can represent the ranges from 0 to 255 or from −128 to 127, resolution can also be defined electrically, and expressed in volts. The minimum change in required to guarantee a change in the output code level is called the least significant bit voltage
40.
Pixel
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The address of a pixel corresponds to its physical coordinates. LCD pixels are manufactured in a grid, and are often represented using dots or squares. Each pixel is a sample of an image, more samples typically provide more accurate representations of the original. The intensity of each pixel is variable, in color imaging systems, a color is typically represented by three or four component intensities such as red, green, and blue, or cyan, magenta, yellow, and black. The word pixel is based on a contraction of pix and el, the word pixel was first published in 1965 by Frederic C. Billingsley of JPL, to describe the elements of video images from space probes to the Moon. Billingsley had learned the word from Keith E. McFarland, at the Link Division of General Precision in Palo Alto, McFarland said simply it was in use at the time. The word is a combination of pix, for picture, the word pix appeared in Variety magazine headlines in 1932, as an abbreviation for the word pictures, in reference to movies. By 1938, pix was being used in reference to pictures by photojournalists. The concept of a picture element dates to the earliest days of television, some authors explain pixel as picture cell, as early as 1972. In graphics and in image and video processing, pel is often used instead of pixel, for example, IBM used it in their Technical Reference for the original PC. A pixel is generally thought of as the smallest single component of a digital image, however, the definition is highly context-sensitive. For example, there can be printed pixels in a page, or pixels carried by electronic signals, or represented by digital values, or pixels on a display device, or pixels in a digital camera. This list is not exhaustive and, depending on context, synonyms include pel, sample, byte, bit, dot, Pixels can be used as a unit of measure such as,2400 pixels per inch,640 pixels per line, or spaced 10 pixels apart. For example, a high-quality photographic image may be printed with 600 ppi on a 1200 dpi inkjet printer, even higher dpi numbers, such as the 4800 dpi quoted by printer manufacturers since 2002, do not mean much in terms of achievable resolution. The more pixels used to represent an image, the closer the result can resemble the original, the number of pixels in an image is sometimes called the resolution, though resolution has a more specific definition.3 megapixels. The pixels, or color samples, that form an image may or may not be in one-to-one correspondence with screen pixels. In computing, a composed of pixels is known as a bitmapped image or a raster image
41.
Magnetic tape data storage
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Magnetic tape data storage is a system for storing digital information on magnetic tape using digital recording. Modern magnetic tape is most commonly packaged in cartridges and cassettes, the device that performs writing or reading of data is a tape drive. Autoloaders and tape libraries automate cartridge handling, for example, a common cassette-based format is Linear Tape-Open, which comes in a variety of densities and is manufactured by several companies. Sony announced in 2014 that they had developed a storage technology with the highest reported magnetic tape data density,148 Gbit/in². Initially, magnetic tape for storage was wound on 10. 5-inch reels. This de facto standard for computer systems persisted through the late 1980s. Tape cartridges and cassettes were available as early as the mid-1970s and were used with small computer systems. With the introduction of the IBM3480 cartridge in 1984, large computer systems started to move away from open reel tapes, magnetic tape was first used to record computer data in 1951 on the Eckert-Mauchly UNIVAC I. The UNISERVO drive recording medium was a metal strip of 0. 5-inch wide nickel-plated phosphor bronze. Recording density was 128 characters per inch on eight tracks at a speed of 100 in/s. Of the eight tracks, six were data, one was a parity track, making allowance for the empty space between tape blocks, the actual transfer rate was around 7,200 characters per second. A small reel of mylar tape provided separation from the metal tape, IBM computers from the 1950s used ferrous-oxide coated tape similar to that used in audio recording. IBMs technology soon became the de facto industry standard, magnetic tape dimensions were 0. 5-inch wide and wound on removable reels up to 10.5 inches in diameter. Different tape lengths were available with 1,200 feet and 2,400 feet on mil, during the 1980s, longer tape lengths such as 3,600 feet became available using a much thinner PET film. Most tape drives could support a maximum size of 10.5 inches. CDC used IBM compatible 1/2 inch magnetic tapes, but also offered a 1 inch wide variant, a so-called mini-reel was common for smaller data sets, such as for software distribution. These were 7-inch reels, often with no fixed length—the tape was sized to fit the amount of data recorded on it as a cost-saving measure. Early IBM tape drives, such as the IBM727 and IBM729, were mechanically sophisticated floor-standing drives that used vacuum columns to buffer long u-shaped loops of tape
42.
Floppy disk
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Floppy disks are read and written by a floppy disk drive. Floppy disks, initially as 8-inch media and later in 5¼-inch and 3½-inch sizes, were a form of data storage and exchange from the mid-1970s into the mid-2000s. These formats are usually handled by older equipment and these disks and associated drives were produced and improved upon by IBM and other companies such as Memorex, Shugart Associates, and Burroughs Corporation. The term floppy disk appeared in print as early as 1970, in 1976, Shugart Associates introduced the first 5¼-inch FDD. By 1978 there were more than 10 manufacturers producing such FDDs, there were competing floppy disk formats, with hard- and soft-sector versions and encoding schemes such as FM, MFM and GCR. The 5¼-inch format displaced the 8-inch one for most applications, the most common capacity of the 5¼-inch format in DOS-based PCs was 360 kB and in 1984 IBM introduced the 1.2 MB dual-sided floppy disk along with its PC-AT model. IBM started using the 720 kB double-density 3½-inch microfloppy disk on its Convertible laptop computer in 1986 and these disk drives could be added to older PC models. In 1988 IBM introduced a drive for 2.88 MB DSED diskettes in its top-of-the-line PS/2 models, throughout the early 1980s, limitations of the 5¼-inch format became clear. Originally designed to be practical than the 8-inch format, it was itself too large, as the quality of recording media grew. A number of solutions were developed, with drives at 2-, 2½-, 3-, 3½-, the large market share of the 5¼-inch format made it difficult for these new formats to gain significant market share. A variant on the Sony design, introduced in 1982 by a number of manufacturers, was then rapidly adopted. By the end of the 1980s, 5¼-inch disks had been superseded by 3½-inch disks, by the mid-1990s, 5¼-inch drives had virtually disappeared, as the 3½-inch disk became the predominant floppy disk. Floppy disks became ubiquitous during the 1980s and 1990s in their use with computers to distribute software, transfer data. Before hard disks became affordable to the population, floppy disks were often used to store a computers operating system. Most home computers from that period have a primary OS and BASIC stored as ROM, by the early 1990s, the increasing software size meant large packages like Windows or Adobe Photoshop required a dozen disks or more. In 1996, there were a five billion standard floppy disks in use. Then, distribution of packages was gradually replaced by CD-ROMs, DVDs. External USB-based floppy disk drives are available, many modern systems provide firmware support for booting from such drives
