1.
Sinclair Research
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Sinclair Research Ltd is a British consumer electronics company founded by Clive Sinclair in Cambridge. In 1980, Clive Sinclair entered the computer market with the ZX80 at £99.95. In 1982 the ZX Spectrum was released, becoming the UKs best selling computer, Sinclair Research Ltd still exists as a one-man company, continuing to market Clive Sinclairs inventions. On 25 July 1961, Clive Sinclair founded his first company, the company developed hi-fi products, radios, calculators and scientific instruments. When it became clear that Radionics was failing, Sinclair took steps to ensure that he would be able to continue to pursue his commercial goals, in February 1975, he changed the name of Ablesdeal Ltd to Westminster Mail Order Ltd. The name was changed to Sinclair Instrument Ltd in August 1975, the companys first product was a watch-like Wrist Calculator. In July 1977, Sinclair Instrument Ltd was renamed Science of Cambridge Ltd, around the same time, Ian Williamson showed Chris Curry a prototype microcomputer based on a National Semiconductor SC/MP microprocessor and parts from a Sinclair calculator. Curry was impressed and encouraged Sinclair to adopt it as a product, in June 1978, Science of Cambridge launched its MK14 microcomputer in kit form. In May 1979, Jim Westwood, Sinclairs chief engineer, designed a new microcomputer based on the Zilog Z80 microprocessor, Sinclair Instrument Ltd introduced the computer as the ZX80 in February 1980, as both a kit and ready-built. In November 1979, Science of Cambridge Ltd was renamed Sinclair Computers Ltd, in March 1981, Sinclair Computers was renamed Sinclair Research Ltd and the Sinclair ZX81 was launched. In February 1982, Timex Corporation obtained a license to manufacture, in April the ZX Spectrum was launched. In July Timex launched the TS1000 in the United States, in March 1982 Sinclair Research Ltd made an £8. 55m profit on turnover of £27. 17m, including a £383,000 government grant to develop a flat screen. In 1982 Clive Sinclair converted the Barker & Wadsworth mineral water bottling factory at 25 Willis Road, Cambridge, in January 1983 the ZX Spectrum personal computer was presented at the Las Vegas Consumer Electronics Show. In September the Sinclair TV80 pocket television was launched, but was a commercial failure, in 1983 the company bought Milton Hall in the village of Milton, Cambridgeshire, for £2m, establishing its MetaLab research and development facility there. In late 1983 Timex decided to out of the Timex Sinclair venture which. However, Timex computers continued to be produced for years in other countries. Timex Portugal launched improved versions, the TS2048 and 2068, that also developed and launched the FDD3000. The Sinclair QL was announced on 12 January 1984, shortly before the Apple Macintosh went on sale, the QL was nowhere near as successful as Sinclairs earlier computers
2.
Timex Group USA
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Timex Group USA, Inc. is an American manufacturer company founded in 1854. The company is now a wholly owned subsidiary of the Dutch conglomerate Timex Group B. V, in 1854, the company was founded as the Waterbury Clock Company in nearby Waterbury, Connecticut. In 1944, the company was thought to have become insolvent, in 2008, the company was acquired by Timex Group B. V, and was renamed into Timex Group USA. Shortly after purchasing the Waterbury Clock Company in 1941, founder Thomas Olsen had renamed the company Timex, as a portmonteau of Time, in 1854, Waterbury, Connecticut-based brass manufacturer Benedict & Burnham created Waterbury Clock Company to manufacture clocks using brass wheels and gears. Waterbury Clock Company was legally incorporated on 27 March 1857, as an independent business with $60,000 in capital. The American clock industry, with scores of companies located in Connecticuts Naugatuck Valley, was producing millions of clocks, earning the region the nickname, the Waterbury Clock Company was one of the largest producers for both domestic sales and export, primarily to Europe. Today its successor, Timex Group USA, Inc. is the remaining watch company in the region. Originally, the company produced clocks as less expensive alternatives to the high-end European counterparts of the time, the Jumbo was put on the market in New York City on a trial basis, catching the attention of Robert H. Ingersoll, a salesman and eventual marketing pioneer. In 1896, Ingersoll introduced the Ingersoll Yankee, a pocket watch supplied by Waterbury Clock Company. These watches gained great popularity that they became known as the watch that made the dollar famous. In 1877, a new prototype was introduced to Benedict and Burnham for a pocket watch made of 58 parts. They immediately set aside a portion of their machine shop. The company was reorganized as the New England Watch Company in 1898 as its London sales office was placed into liquidation. The company continued to focus on high-priced watch models and eventually fell into receivership, Robert H. Ingersoll & Bro. bought the Waterbury plant and began manufacturing Ingersoll Watches there in 1914. With the American entry into World War I there were new demands for timepiece design, artillery gunners needed an easy way to calculate and read time while still being able to work the guns. The powerful Ingersoll brand name was continued in the United States by Waterbury Clock into the 1950s, no longer part of Waterbury Clock Company, Ingersoll Ltd. continued to produce the Ingersoll watch brand independently for the European and other international markets. Following the Great Depression and a period of hardship for the company, in 1930, a license agreement was reached with Walt Disney, resulting in the production of the famous Mickey Mouse watches and clocks under the Ingersoll brand name. The new Mickey Mouse timepieces were introduced to the public at the Chicago Worlds Fair in June 1933 and quickly became the companys first million-dollar line, in 1940, Thomas Olsen and Joakim Lehmkuhl fled Norway with their families because of the Nazi invasion
3.
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
4.
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
5.
Floppy disk variants
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The floppy disk is a ubiquitous data storage and transfer device from the mid-1970s well into the 2000s. The standard Commodore Group Coded Recording scheme used in 1541 and compatibles employed four different data rates depending upon track position. Tracks 1 to 17 had 21 sectors,18 to 24 had 19,25 to 30 had 18, many programs such as GEOS bypass Commodores DOS completely, and replace it with fast-loading programs in the 1541 drive. Equipped with one of these drives, the C128 is able to access both C64 and CP/M disks, as it needs to, as well as MS-DOS disks, at least one commercial program, Big Blue Reader by SOGWAP software was available to perform the task. Commodore also developed a 3½-inch 800 KB disk format for its 8-bit machines with the 1581 disk drive, the combination of DOS and hardware for Atari 8-bit floppy usage allows sectors numbered from 1 to 720. The DOSs 2.0 disk bitmap provides information on sector allocation, as a result, sector 720 cannot be written to by the DOS. Some companies used a scheme where hidden data was put in sector 720 that cannot be copied through the DOS copy option. Another more-common early copy-protected scheme simply does not record important sectors as allocated in the FAT, all of these early techniques were thwarted by the first program that simply duplicated all 720 sectors. That unusual 127 KB format allows sectors 1-720 to still be read on a single-density 810 disk drive, a true 180K double-density Atari floppy format uses 128-byte sectors for sectors 1-3, then 256-byte sectors for 4-720. The first three sectors typically contain boot code as used by the onboard ROM OS, it is up to the boot program to recognize the density of the formatted disk structure. Under the Atari DOS scheme, sector 360 is the FAT sector map, the Atari-brand DOS versions and compatible use three bytes per sector for housekeeping and to link-list to the next sector. Third-party DOS systems added features such as double-sided drives, subdirectories, well-known 3rd party Atari DOS products include SmartDOS, TopDos, MyDos and SpartaDOS. The Commodore Amiga computers use an 880 KB format on a 3½-inch floppy, because the entire track is written at once, intersector gaps can be eliminated, saving space. Because of this, foreign formats such as the IBM PC-compatible can be handled with ease, with the correct filesystem driver, an Amiga can theoretically read any arbitrary format on the 3½-inch floppy, including those recorded at a slightly different rotation rate. On the PC, however, there is no way to read an Amiga disk without special hardware, such as a CatWeasel, and this drive was introduced with the launch of the Amiga 4000, although the later Amiga 1200 was only fitted with the standard DD drive. The Amiga HD disks can handle 1760 KB, but using software programs they can hold even more data. A company named Kolff Computer Supplies also made an external HD floppy drive available which can handle HD format diskettes on all Amiga computer systems, because of storage reasons, the use of emulators and preserving data, many disks were packed into disk images. Currently popular formats are. ADF. DMS and. IPF files, the DiskMasher format is copy-protected and has problems storing particular sequences of bits due to bugs in the compression algorithm, but was widely used in the pirate and demo scenes
6.
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
7.
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
8.
Zilog Z80
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The Z80 CPU is an 8-bit based microprocessor. It was introduced by Zilog in 1976 as the companys first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his employees at Zilog from early 1975 until March 1976. With the revenue from the Z80, the company built its own chip factories, the Zilog Z80 was a software compatible extension and enhancement of the Intel 8080 and, like it, was mainly aimed at embedded systems. In the early 1980s, the Z80 was the most commonly used CPU of all time, Zilog licensed the Z80 to the US-based Synertek and Mostek, that had helped them with initial production, as well as to a European second source manufacturer, SGS. The design was copied also by several Japanese, East European and Russian manufacturers and this enabled the Z80 to gain acceptance in the world market since large companies like NEC, Toshiba, Sharp, and Hitachi, started to manufacture the device. The Z80 came about when physicist Federico Faggin left Intel at the end of 1974 to found Zilog with Ralph Ungermann, at Fairchild Semiconductor, and later at Intel, Faggin had been working on fundamental transistor and semiconductor manufacturing technology. He also developed the design methodology used for memories and microprocessors at Intel and led the work on the Intel 4004. Masatoshi Shima, the logic and transistor level-designer of the 4004. By March 1976, Zilog had developed the Z80 as well as an accompanying assembler based development system for its customers, and by July 1976, early Z80s were manufactured by Synertek and Mostek, before Zilog had its own manufacturing factory ready, in late 1976. Masatoshi Shima designed most of the microarchitecture as well as the gate and transistor levels of the Z80 CPU, assisted by a number of engineers. CEO Federico Faggin was actually involved in the chip layout work. Faggin worked 80 hours a week in order to meet the tight schedule given by the financial investors, a non maskable interrupt which can be used to respond to power down situations and/or other high priority events. Two separate register files, which could be switched, to speed up response to interrupts such as fast asynchronous event handlers or a multitasking dispatcher. Although they were not intended as extra registers for general code, less hardware required for power supply, clock generation and interface to memory and I/O Single 5-volt power supply. A built-in DRAM refresh mechanism that would otherwise have to be provided by external circuitry, a special reset function which clears only the program counter so that a single Z80 CPU could be used in a development system such as an in-circuit emulator. The Z80 took over from the 8080 and its offspring, the 8085, in the processor market, perhaps a key to the initial success of the Z80 was the built-in DRAM refresh, and other features which allowed systems to be built with fewer support chips. For the original NMOS design, the specified upper frequency limit increased successively from the introductory 2.5 MHz, via the well known 4 MHz
9.
ZX81
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The ZX81 is a home computer produced by Sinclair Research and manufactured in Scotland by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclairs ZX80 and was designed to be a low-cost introduction to home computing for the general public and it was hugely successful, and more than 1.5 million units were sold before it was discontinued. The ZX81 found commercial success in other countries, notably the United States. Timex manufactured and distributed it under licence and enjoyed a substantial, Timex later produced its own versions of the ZX81 for the US market – the Timex Sinclair 1000 and Timex Sinclair 1500. Unauthorised clones of the ZX81 were produced in several countries, the ZX81 was designed to be small, simple, and above all cheap, using as few components as possible to keep the cost down. Video output was to a set rather than a dedicated monitor. Programs and data were loaded and saved onto audio tape cassettes and it had only four silicon chips on board and a mere 1 KB of memory. The machine had no power switch or any moving parts and used a membrane keyboard for manual input. The ZX81s limitations prompted the emergence of a market in third-party peripherals to improve its capabilities. Such limitations, however, achieved Sinclairs objective of keeping the cost of the machine as low as possible and its distinctive case and keyboard brought its designer, Rick Dickinson, a Design Council award. The ZX81 could be bought by mail order in kit form or pre-assembled, in what was then a major innovation, it was the first cheap mass-market home computer that could be bought from high street stores, led by W. H. Smith and soon many other retailers. The ZX81 marked the first time that computing in Britain became an activity for the public, rather than the preserve of businesspeople. It inspired the creation of a community of enthusiasts, some of whom founded their own businesses producing software and hardware for the ZX81. Many went on to play a role in the British computer industry in later years. The ZX81s commercial success made Sinclair Research one of Britains leading computer manufacturers and earned a fortune, the ZX81 came with 1 KB of on-board memory that could officially be expanded externally to 16 KB. Its single circuit board was housed inside a plastic case measuring 167 millimetres deep by 40 millimetres high. The memory was provided by either a single 4118 or two 2114 RAM chips. There were only three other chips on board, a 3.5 MHz Z80A 8-bit microprocessor from NEC, an uncommitted logic array chip from Ferranti, the entire machine weighed just 350 grams
10.
Sinclair QL
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The Sinclair QL, is a personal computer launched by Sinclair Research in 1984, as an upper-end counterpart to the Sinclair ZX Spectrum. The QL was aimed at the home user and professional and executive users markets from small to large businesses and higher educational establishments. Based on a Motorola 68008 processor clocked at 7.5 MHz, two built-in Microdrive tape-loop cartridge drives provided mass storage, in place of the more expensive floppy disk drives found on similar systems of the era. Interfaces included a slot, ROM cartridge socket, dual RS-232 ports, proprietary QLAN local area network ports, dual joystick ports. Both screen modes used a 32 kB framebuffer in main memory, the hardware is capable of switching between two different areas of memory for the framebuffer, thus allowing double buffering. However, this would have used 64 KB of the standard machines 128 kB of RAM, the alternative and much improved operating system Minerva does provide full support for the second framebuffer. When connected to a normally-adjusted TV or monitor, the QLs video output would overscan horizontally and this was reputed to have been due to the timing constants in the ZX8301 chip being optimised for the flat-screen CRT display originally intended for the QL. Internally, the QL comprised the CPU, two ULAs, and an Intel 8049 microcontroller, the ZX8301 or Master Chip implemented the video display generator and also provided DRAM refresh. The ZX8302, or Peripheral Chip, interfaced to the RS-232 ports Microdrives, QLAN ports, real-time clock, the 8049 ran at 11 MHz and acted as a keyboard/joystick interface, RS-232 receive buffer and audio generator. The QL was bundled with a suite written by Psion. The QL used British Telecom type 631W plugs for serial cables except for QLs built by Samsung for export markets, joysticks connected to the QL with similar type 630W plugs. The QL was originally conceived in 1981 under the code-name ZX83, as a computer for business users, with a built-in ultra-thin flat-screen CRT display, printer. As development progressed it became clear that the portability features were over-ambitious. The electronics were designed by David Karlin, who joined Sinclair Research in summer 1982. The industrial design was done by Rick Dickinson, who designed the ZX81. Sinclair had commissioned GST Computer Systems to produce the system for the machine. GSTs OS, designed by Tim Ward, was made available as 68K/OS. The tools developed by GST for the QL would later be used on the Atari ST, the QL was designed to be more powerful than the IBM Personal Computer, and comparable to Apples Macintosh
11.
Black and white
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Black and white, often abbreviated B/W or B&W, and hyphenated black-and-white when used as an adjective, is any of several monochrome forms in visual arts. Black-and-white images are not usually starkly contrasted black and white and they combine black and white in a continuum producing a range of shades of gray. Even when most studios had the capability to make color films they were not heavily utilized as using the Technicolor process was expensive, for the years 1940–1966, a separate Academy Award for Best Art Direction was given for black-and-white movies along with one for color. Television, Television program was first transmitted in black-and-white, scottish inventor John Logie Baird demonstrated the worlds first color television transmission on July 3,1928 using a mechanical process. Some color broadcasts in the US began in the 1950s, with color becoming common in industrialized nations during the late 1960s. In the United States, the Federal Communications Commission settled on a color NTSC standard in 1953, color television became more widespread in the U. S. between 1963 and 1967, when the CBS and ABC networks joined NBC in broadcasting full color schedules. Canada began airing color television in 1966 while the United Kingdom began to use a different color system from July 1967 known as PAL. The Republic Of Ireland followed in 1970, in China, black and white television sets were the norm until as late as the 1990s, color TVs not outselling them until about 1989. While seldom used now, many consumer camcorders have the ability to record in black-and-white. Photography, Photographs were either black-and-white or shades of sepia, color photography was originally rare and expensive and again often containing inaccurate hues. Color photography became more common from the mid-20th century, Today, black-and-white is a niche market for photographers who use the medium for artistic purposes. This can take the form of film or digital conversion to grayscale. For amateur use certain companies such as Kodak manufactured black-and-white disposable cameras until 2009, also, certain films are produced today which give black-and-white images using the ubiquitous C41 color process. Printing press, Most American newspapers were black-and-white until the early 1980s, The New York Times, some claim that USA Today was the major impetus for the change to color. In the UK, color was only introduced from the mid-1980s. Even today, many newspapers restrict color photographs to the front, similarly, daily comic strips in newspapers were traditionally black-and-white with color reserved for Sunday strips. Sometimes color is reserved for the cover, magazines such as Jet magazine were either all or mostly black-and-white until the end of the 2000s when it became all-color. Manga are typically published in black-and-white although now it is part of its image, many school yearbooks are still entirely or mostly in black-and-white
12.
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
13.
Commodore 64
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The Commodore 64, also known as the C64, C-64, C=64, or occasionally CBM64 or VIC-64 in Sweden, is an 8-bit home computer introduced in January 1982 by Commodore International. It is listed in the Guinness World Records as the single computer model of all time. Volume production started in early 1982, marketing in August for US$595, preceded by the Commodore VIC-20 and Commodore PET, the C64 took its name from its 64 kilobytes of RAM. It had superior sound and graphical specifications compared to earlier systems such as the Apple II and Atari 800, with multi-color sprites. The C64 dominated the low-end computer market for most of the 1980s. Sam Tramiel, a later Atari president and the son of Commodores founder, said in a 1989 interview, When I was at Commodore we were building 400,000 C64s a month for a couple of years. In the UK market, the C64 faced competition from the BBC Micro and the ZX Spectrum, part of the Commodore 64s success was its sale in regular retail stores instead of only electronics and/or computer hobbyist specialty stores. Commodore produced many of its parts in-house to control costs, including custom integrated circuit chips from MOS Technology and it has been compared to the Ford Model T automobile for its role in bringing a new technology to middle-class households via creative and affordable mass-production. Approximately 10,000 commercial software titles have made for the Commodore 64 including development tools, office productivity applications. C64 emulators allow anyone with a computer, or a compatible video game console. The C64 is also credited with popularizing the computer demoscene and is used today by some computer hobbyists. In 2008,17 years after it was taken off the market, in January 1981, MOS Technology, Inc. Commodores integrated circuit design subsidiary, initiated a project to design the graphic, Design work for the chips, named MOS Technology VIC-II and MOS Technology SID, was completed in November 1981. Commodore then began a game console project that would use the new chips—called the Ultimax or the Commodore MAX Machine and this project was eventually cancelled after just a few machines were manufactured for the Japanese market. At the same time, Robert Bob Russell and Robert Bob Yannes were critical of the current product line-up at Commodore, with the support of Al Charpentier and Charles Winterble, they proposed to Commodore CEO Jack Tramiel a true low-cost sequel to the VIC-20. Tramiel dictated that the machine should have 64 KB of random-access memory, although 64-Kbit dynamic random-access memory chips cost over US$100 at the time, he knew that DRAM prices were falling, and would drop to an acceptable level before full production was reached. The product was named the VIC-40 as the successor to the popular VIC-20. The team that constructed it consisted of Yash Terakura, Bob Russell, Bob Yannes, the design, prototypes and some sample software were finished in time for the show, after the team had worked tirelessly over both Thanksgiving and Christmas weekends
14.
Software
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Computer software, or simply software, is that part of a computer system that consists of data or computer instructions, in contrast to the physical hardware from which the system is built. In computer science and software engineering, computer software is all information processed by computer systems, programs, computer software includes computer programs, libraries and related non-executable data, such as online documentation or digital media. Computer hardware and software require each other and neither can be used on its own. At the lowest level, executable code consists of machine language instructions specific to an individual processor—typically a central processing unit, a machine language consists of groups of binary values signifying processor instructions that change the state of the computer from its preceding state. For example, an instruction may change the value stored in a storage location in the computer—an effect that is not directly observable to the user. An instruction may also cause something to appear on a display of the computer system—a state change which should be visible to the user. The processor carries out the instructions in the order they are provided, unless it is instructed to jump to a different instruction, the majority of software is written in high-level programming languages that are easier and more efficient for programmers, meaning closer to a natural language. High-level languages are translated into machine language using a compiler or an interpreter or a combination of the two, an outline for what would have been the first piece of software was written by Ada Lovelace in the 19th century, for the planned Analytical Engine. However, neither the Analytical Engine nor any software for it were ever created, the first theory about software—prior to creation of computers as we know them today—was proposed by Alan Turing in his 1935 essay Computable numbers with an application to the Entscheidungsproblem. This eventually led to the creation of the academic fields of computer science and software engineering. Computer science is more theoretical, whereas software engineering focuses on practical concerns. However, prior to 1946, software as we now understand it—programs stored in the memory of stored-program digital computers—did not yet exist, the first electronic computing devices were instead rewired in order to reprogram them. On virtually all platforms, software can be grouped into a few broad categories. There are many different types of software, because the range of tasks that can be performed with a modern computer is so large—see list of software. System software includes, Operating systems, which are collections of software that manage resources and provides common services for other software that runs on top of them. Supervisory programs, boot loaders, shells and window systems are parts of operating systems. In practice, an operating system bundled with additional software so that a user can potentially do some work with a computer that only has an operating system. Device drivers, which operate or control a particular type of device that is attached to a computer, utilities, which are computer programs designed to assist users in the maintenance and care of their computers
15.
Computer hardware
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Computer hardware is the collection of physical components that constitute a computer system. By contrast, software is instructions that can be stored and run by hardware, hardware is directed by the software to execute any command or instruction. A combination of hardware and software forms a usable computing system, the template for all modern computers is the Von Neumann architecture, detailed in a 1945 paper by Hungarian mathematician John von Neumann. The meaning of the term has evolved to mean a stored-program computer in which an instruction fetch and this is referred to as the Von Neumann bottleneck and often limits the performance of the system. For the third year, U. S. business-to-business channel sales increased. The impressive growth was the fastest sales increase since the end of the recession, sales growth accelerated in the second half of the year peaking in fourth quarter with a 6.9 percent increase over the fourth quarter of 2012. There are a number of different types of system in use today. The personal computer, also known as the PC, is one of the most common types of computer due to its versatility, laptops are generally very similar, although they may use lower-power or reduced size components, thus lower performance. The computer case is a plastic or metal enclosure that houses most of the components, a case can be either big or small, but the form factor of motherboard for which it is designed matters more. A power supply unit converts alternating current electric power to low-voltage DC power for the components of the computer. Laptops are capable of running from a battery, normally for a period of hours. The motherboard is the component of a computer. It is usually cooled by a heatsink and fan, or water-cooling system, most newer CPUs include an on-die Graphics Processing Unit. The clock speed of CPUs governs how fast it executes instructions, many modern computers have the option to overclock the CPU which enhances performance at the expense of greater thermal output and thus a need for improved cooling. The chipset, which includes the bridge, mediates communication between the CPU and the other components of the system, including main memory. Random-Access Memory, which stores the code and data that are being accessed by the CPU. For example, when a web browser is opened on the computer it takes up memory, RAM usually comes on DIMMs in the sizes 2GB, 4GB, and 8GB, but can be much larger. Read-Only Memory, which stores the BIOS that runs when the computer is powered on or otherwise begins execution, the BIOS includes boot firmware and power management firmware
16.
Clive Sinclair
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Sir Clive Marles Sinclair is an English entrepreneur and inventor, most commonly known for his work in consumer electronics in the late 1970s and early 1980s. After spending several years as assistant editor of Instrument Practice, Sinclair founded Sinclair Radionics in 1961, knighted in 1983, Sinclair formed Sinclair Vehicles and released the Sinclair C5, a battery electric vehicle that was also a commercial failure. Sinclairs father and grandfather were engineers, both had been apprentices at Vickers the shipbuilders and his grandfather George Sinclair was an innovative naval architect who got the paravane, a mine sweeping device, to work. George Sinclairs son, George William Bill Sinclair, wanted to take orders or become a journalist. His father suggested he train as an engineer first, Bill became a mechanical engineer, at the outbreak of World War II in 1939 he was running his own machine tools business in London, and later worked for the Ministry of Supply. Clive Sinclair was born to George Sinclair and Thora Edith Ella Marles in 1940 near Richmond and he and his mother left London for safety to stay with an aunt in Devon, where they eventually travelled to Teignmouth. A telegram arrived shortly afterwards, bringing the news that their home in Richmond had been bombed, Sinclairs father found a house in Bracknell in Berkshire. His brother Iain was born in 1943 and his sister Fiona in 1947, at the age of 14, Sinclair designed a submarine. During holidays he could pursue his ideas and teach himself what he wanted to know, Sinclair had little interest in sports and found himself out of place at school. He preferred the company of adults, which he got only from his family, Sinclair attended Boxgrove Preparatory School, excelling in mathematics. By the time he was ten, his father had financial problems and he had branched out from machine tools and planned to import miniature tractors from the U. S. he had to give up the business. Because of his fathers problems, Sinclair had to move several times. After a time at Reading School, Sinclair took his O-levels at Highgate School in London in 1955 and A-levels in physics, pure maths, during his early years, Sinclair earned money mowing lawns and washing up, and earned 6d more than permanent staff in a café. Later he went for holiday jobs at electronic companies, at Solatron he inquired about the possibility of electrically propelled personal vehicles. Sinclair applied for a job at Mullard and took one of his circuit designs. While still at school he wrote his first article for Practical Wireless, Sinclair did not want to go to university when he left school at the age of 18 and instead he sold miniature electronic kits by mail order to the hobby market. Sinclairs Micro Kit was formalised in a book dated 19 June 1958 three weeks before his A-levels. Sinclair drew a radio circuit, Model Mark I, with a components list, cost per set 9/11, plus coloured wire and solder, nuts and bolts, also in the book are advertisement rates for Radio Constructor and Practical Wireless
17.
Dragon 32
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The Dragon 32 and Dragon 64 are home computers that were built in the 1980s. The model numbers reflect the difference between the two machines, which have 32 and 64 kilobytes of RAM, respectively. In the early 1980s, the British home computer market was booming, new machines were released almost monthly. In August 1982, Dragon Data joined the fray with the Dragon 32, the computers sold quite well initially and attracted the interest of several independent software developers, most notably Microdeal. A magazine, Dragon User, also began shortly after the machines launch. The Dragon was also unable to display lower-case letters easily, some more sophisticated applications would synthesise them using high-resolution graphics modes. Simpler programs just managed without lower case and this effectively locked it out of the then-blooming educational market. As a result of limitations, the Dragon was not a commercial success. The Dragon is built around the Motorola MC6809E processor running at 0.89 MHz and this was an advanced 8-bit CPU design, having, among other things, limited 16-bit capabilities. Manufacturing variances mean that not all Dragons are able to function at higher speed. POKE65494,0 returns the speed to normal, POKE65497,0 pushes the speed yet higher but the display is lost until a slower speed is restored. The Dragon also used the SN74LS783/MC6883 Synchronous Address Multiplexer and the MC6847 Video Display Generator, i/O was provided by two MC6821 Peripheral Interface Adapters. Many Dragon 32s were upgraded by their owners to 64 kB of memory, a few were further expanded to 128 kB,256 kB, or 512 kB, with home-built memory controllers/memory management units. A broad range of peripherals exist for the Dragon 32/64, although neither machine has a built-in disk operating system, DragonDOS was supplied as part of the disk controller interface from Dragon Data Ltd. The numerous external ports, including the standard RS-232 on the 64, an unusual feature was a monitor port for connection of a computer monitor, as an alternative to the TV output. This was rarely used due to the cost of dedicated monitors at that time, the port is actually a Composite Video port and can be used to connect the Dragon 32 to most modern TVs to deliver a much better picture. The Dragon uses analogue joysticks, unlike most systems of the time used less versatile. Other uses for the ports include light pens
18.
Oric
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With the success of the Sinclair ZX Spectrum, Tangerines backers had suggested a home computer and Tangerine formed Oric Products International Ltd to develop and release the Oric-1 in 1983. Further computers in the Oric range were released through to 1987 with Eastern European clones being produced into the 1990s, the 48 KB Oric-1 version was actually 64 KB. This additional memory is used by the system to store the Oric DOS software, both Oric-1 versions had a 16 KB ROM containing the operating system and a modified BASIC interpreter. During 1983, around 160,000 Oric-1 computers were sold in the UK, although not quite the 350,000 predicted, this was enough for Oric International to be bought out and given sufficient funding for a successor model, the Atmos. The Oric-1 improved somewhat over the ZX Spectrum with a different keyboard design replacing the ZX Spectrums unusual Chiclet keyboard. In addition the Oric-1 had a sound chip, the programmable GI8912. The two modes were a LORES text only mode with 28 rows of 40 characters and a HIRES mode with 200 rows of 240 pixels above three lines of text. As it was meant for the market, it had a built in television RF modulator as well as RGB output and was meant to work with a basic audio tape recorder to save. Error-checking of recorded programs was bugged, frequently causing user-created programs to fail when loaded back in, an additional feature was a Centronics compatible printer interface. In late 1983 the funding cost for continued development of Oric caused external funding to be sought, the Edenspring money enabled Oric International to release the Oric Atmos, which added a true keyboard and an updated V1.1 ROM to the Oric-1. The faulty tape error checking routine was still there, soon after the Atmos was released, the modem, printer and 3-inch floppy disk drive originally promised for the Oric-1 were announced and released by the end of 1984. A short time after the release of the Atmos machine, a modification for the Oric-1 was issued and advertised in magazines and this modification enabled the Oric-1 user to add a second ROM to a spare ROM-socket on the Oric-1 circuit board. Then, using a switch, the users could then switch between the new Oric Atmos ROM and the original Oric-1 ROM, although the Oric Atmos had not turned around Oric Internationals fortunes, in February 1985, they announced several models including the Oric Stratos/IQ164. Despite their backers putting them into receivership the following day, Oric was bought by French company Eureka, in December 1987, after announcing the Telestrat 2, Oric International went into receivership for the second and final time. Keyboard 57 moving keys with tactile feedback, Full upper and lower case with correctly positioned space bar. Key layout is standard computer type with ESC, CTRL, RETURN, display Will drive a PAL UHF colour or black and white television receiver. RGB output also provided on DlN socket with 270° configuration, screen — Character Mode 28 lines of 40 characters producing display very similar to Teletext. Character set is standard ASCII which is enhanced by the addition of 80 user definable characters, ASCII characters may also be re-defined as these are down loaded into RAM on power-up
19.
BBC Micro
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Designed with an emphasis on education, it was notable for its ruggedness, expandability, and the quality of its operating system. An accompanying 1982 television series The Computer Programme featuring Chris Serle learning to use the machine was also broadcast on BBC2, renamed the BBC Micro, the system was adopted by most schools in the United Kingdom, changing Acorns fortunes. It was also successful as a home computer in the UK despite its high cost. Acorn also employed the machine to simulate and develop the ARM architecture which, many later, has become hugely successful for embedded systems, including tablets. In 2013 ARM was the most widely used 32-bit instruction set architecture, during the early 1980s, the BBC started what became known as the BBC Computer Literacy Project. The BBC wanted to base its project on a microcomputer capable of performing tasks which they could then demonstrate in the TV series The Computer Programme. The list of topics included programming, graphics, sound and music, teletext, controlling external hardware, the Acorn team had already been working on a successor to their existing Atom microcomputer. Known as the Proton, it included better graphics and a faster 2 MHz MOS Technology 6502 central processing unit. The machine was only at the stage at the time. The team worked through the night to get a working Proton together to show the BBC, not only was the Acorn Proton the only machine to match the BBCs specification, it also exceeded it in nearly every parameter. Based on the Proton prototype the BBC signed a contract with Acorn as early as February 1981, by June the BBC Micros specifications and pricing were decided. The machine was released as the BBC Microcomputer on 1 December 1981, BYTE called the BBC Micro Model B a no-compromise computer that has many uses beyond self-instruction in computer technology. In terms of versatility and expansion capability, as with Sinclairs ZX Spectrum and Commodores Commodore 64, both released later in 1982, demand greatly exceeded supply. For some months, there were long delays before customers received the machines they had ordered, efforts were made to market the machine in the United States and West Germany. By October 1983, the US operation reported that American schools had placed orders with it totalling $21 million. In October 1984, while preparing a major expansion of its US dealer network, Acorn claimed sales of 85 per cent of the computers in British schools and that December, Acorn stated its intention to become the market leader in US educational computing. The New York Times considered the inclusion of local area networking to be of importance to teachers. The operation resulted in advertisements by at least one dealer in Interface Age magazine, Acorn became more known for its model B computer than for its other products
20.
Amstrad CPC
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The Amstrad CPC is a series of 8-bit home computers produced by Amstrad between 1984 and 1990. The series spawned a total of six models, The CPC464, CPC664. The CPC models hardware is based on the Zilog Z80A CPU and their computer-in-a-keyboard design prominently features an integrated storage device, either a compact cassette deck or 3 inch floppy disk drive. The main units were sold bundled with either a colour. Additionally, a range of first and third party hardware extensions such as external disk drives, printers. The CPC series was pitched against other home computers used to play video games. During its lifetime, the CPC series sold approximately three million units, the CPC464 was one of the most successful computers in Europe and sold more than two million computers. The CPC464 featured 64 KB RAM and a cassette tape deck. It was introduced in June 1984 in the UK, initial suggested retail prices for the CPC464 were GBP249. 00/DM899.00 with a green screen and GBP359. 00/DM1398.00 with a colour monitor. Following the introduction of the CPC6128 in late 1985, suggested retail prices for the CPC464 were cut by GBP50. 00/DM100.00, in 1990, the 464plus replaced the CPC464 in the model line-up, and production of the CPC464 was discontinued. The CPC664 features 64 KB RAM and an internal 3-inch floppy disk drive and it was introduced in May 1985 in the UK. Initial suggested retail prices for the CPC664 were GBP339. 00/DM1198.00 with a green screen, after the successful release of the CPC464, consumers were constantly asking for two improvements, more memory and an internal disk drive. For Amstrad, the latter was easier to realize, at the deliberately low-key introduction of the CPC664 in May 1985, the machine was positioned not only as the lowest-cost disk system but even the lowest-cost CP/M2.2 machine. In the Amstrad CPC product range the CPC664 complemented the CPC464 which was neither discontinued nor reduced in price, compared to the CPC464, the CPC664s main unit has been significantly redesigned, not only to accommodate the floppy disk drive but also with a redesigned keyboard area. Touted ergonomic by Amstrads promotional material, the keyboard is noticeably tilted to the front with MSX-style cursor keys above the numeric keypad, compared to the CPC464s multicoloured keyboard, the CPC664s keys are kept in a much quieter grey and pale blue colour scheme. The back of the CPC664 main unit features the same connectors as the CPC464, unlike the CPC464s cassette tape drive that could be powered off the main units 5V voltage, the CPC664s floppy disk drive requires an additional 12V voltage. This voltage had to be supplied by an updated version of the bundled green screen/colour monitor. The CPC664 was only produced for six months
21.
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
22.
NEC
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NEC Corporation is a Japanese multinational provider of information technology services and products, headquartered in Minato, Tokyo, Japan. NEC provides IT and network solutions to enterprises, communications services providers and to government agencies. The company was known as the Nippon Electric Company, Limited and its NEC Semiconductors business unit was one of the worldwide top 20 semiconductor sales leaders before merging with Renesas Electronics. NEC is a member of the Sumitomo Group, kunihiko Iwadare and Takeshiro Maeda established Nippon Electric Limited Partnership on August 31,1898 by using facilities that they had bought from Miyoshi Electrical Manufacturing Company. Iwadare acted as the partner, Maeda handled company sales. Western Electric, which had an interest in the Japanese phone market, was represented by Walter Tenney Carleton, Carleton was also responsible for the renovation of the Miyoshi facilities. It was agreed that the partnership would be reorganized as a company when treaty would allow it. On July 17,1899, the treaty between Japan and the United States went into effect. Nippon Electric Company, Limited was organized the day with Western Electric Company to become the first Japanese joint-venture with foreign capital. Ernest Clement and Carleton were named as directors, Maeda and Mototeru Fujii were assigned to be auditors. Iwadare, Maeda and Carleton handled the overall management, the company started with the production, sales and maintenance of telephones and switches. NEC modernized the facilities with the construction of the Mita Plant in 1901 at Mita Shikokumachi. It was completed in December 1902, the Japanese Ministry of Communications adopted a new technology in 1903, the common battery switchboard supplied by NEC. The common battery switchboards powered the subscriber phone, eliminating the need for a permanent magnet generator in each subscribers phone, the switchboards were initially imported, but were manufactured locally by 1909. NEC started exporting telephone sets to China in 1904, in 1905, Iwadare visited Western Electric in the U. S. to see their management and production control. On his return to Japan he discontinued the system of sub-contracting and replaced it with a new system where managers. Inefficiency was also removed from the production process, the company paid higher salaries with incentives for efficiency. New accounting and cost controls were put in place, and time clocks installed, between 1899 and 1907 the number of telephone subscribers in Japan rose from 35,000 to 95,000
23.
Byte
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The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of used to encode a single character of text in a computer. The size of the byte has historically been hardware dependent and no standards existed that mandated the size. The de-facto standard of eight bits is a convenient power of two permitting the values 0 through 255 for one byte, the international standard IEC 80000-13 codified this common meaning. Many types of applications use information representable in eight or fewer bits, the popularity of major commercial computing architectures has aided in the ubiquitous acceptance of the 8-bit size. The unit symbol for the byte was designated as the upper-case letter B by the IEC and IEEE in contrast to the bit, internationally, the unit octet, symbol o, explicitly denotes a sequence of eight bits, eliminating the ambiguity of the byte. It is a respelling of bite to avoid accidental mutation to bit. Early computers used a variety of four-bit binary coded decimal representations and these representations included alphanumeric characters and special graphical symbols. S. Government and universities during the 1960s, the prominence of the System/360 led to the ubiquitous adoption of the eight-bit storage size, while in detail the EBCDIC and ASCII encoding schemes are different. In the early 1960s, AT&T introduced digital telephony first on long-distance trunk lines and these used the eight-bit µ-law encoding. This large investment promised to reduce costs for eight-bit data. The development of microprocessors in the 1970s popularized this storage size. A four-bit quantity is called a nibble, also nybble. The term octet is used to specify a size of eight bits. It is used extensively in protocol definitions, historically, the term octad or octade was used to denote eight bits as well at least in Western Europe, however, this usage is no longer common. The exact origin of the term is unclear, but it can be found in British, Dutch, and German sources of the 1960s and 1970s, and throughout the documentation of Philips mainframe computers. The unit symbol for the byte is specified in IEC 80000-13, IEEE1541, in the International System of Quantities, B is the symbol of the bel, a unit of logarithmic power ratios named after Alexander Graham Bell, creating a conflict with the IEC specification. However, little danger of confusion exists, because the bel is a used unit
24.
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
25.
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
26.
Richard Altwasser
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Richard Francis Altwasser is a British engineer and inventor, responsible for the hardware design of the ZX Spectrum. Altwasser graduated at Trinity College, Cambridge, with a degree in engineering in June 1978 and he was hired by Sinclair Research in September 1980. His first assigned job was to some programs to demonstrate the capabilities of the new 8 kB ROM and 16 kB RAM expansion for the ZX80. After that, he worked on the circuit board of the ZX81. After the launch of the ZX81, Altwasser was promoted to the development team and worked on the development of the ZX Spectrum. His main contribution was the design of the mode using less than 7 kilobytes of memory. He also participated in the stages of the development of the ZX Microdrive. Altwasser left Sinclair at the beginning of May 1982 to establish his own company, along with Steve Vickers, author of the Spectrums ROM firmware, provisionally called Rainbow Computing Co. the company later became Jupiter Cantab Limited. Jupiter Cantab launched only one product, a home computer called Jupiter Ace. The Ace was a failure both in the UK and in the U. S. markets, the company went bankrupt in November 1983. In 1986 Altwasser became the director at Amstrad. The same year Amstrad, already itself a home computer manufacturer. Altwasser left Amstrad in 1992, taking on a number of director and executive jobs in other companies, as of 2011 he gives his occupation as a reader at Portishead parish. «Display for a computer» ZX Spectrums chief designers reunited 30 years on
27.
Rick Dickinson
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Rick Dickinson is a British industrial designer. Dickinson graduated from Newcastle Polytechnic in 1979 with a First Class Bachelor of Arts Honours degree in Design for Industry, the Design for Industry degree was the first of its kind, formerly a three-year Industrial Design degree. The new course with two terms for industrial placements, extended the degree to four years and the introduction of the term sandwich. Dickinson joined Sir Clive Sinclairs Sinclair Research Ltd in December 1979, Sinclair Research offices were at 6 Kings Parade, Cambridge. Rick Dickinson was the industrial designer of Sinclair Research Ltd. He designed the ZX80 and ZX81 home computer cases, including the touch-sensitive keyboard, the ZX81 won a British Design Council award in 1981. It won a Haus Industrieform award and is in a permanent collection in Essen, the Sinclair QL won an Italian design award at the Smau Industrial Design Award. In 1986, he founded Dickinson Associates, a design consultancy based in Cambridge. That year he produced the design for an early laptop computer. In 1987 he was commissioned by Alan Sugar to create the design concept for Amstrads first portable computer. In 1989 Rick Dickinson, Christopher Curry, and Keith Dunning had a re-think of the famous MacArthur field microscope and Rick designed the Lensman microscope, a portable field microscope. In 1991 the Lensman microscope won the BBC design awards, The Prince Of Wales Award For Industrial Innovation And Production, Dickinson Associates were also the designers of the Gizmondo handheld console
28.
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
29.
Television
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Television or TV is a telecommunication medium used for transmitting moving images in monochrome, or in color, and in two or three dimensions and sound. The term can refer to a set, a television program. Television is a medium for entertainment, education, news, politics, gossip. Television became available in experimental forms in the late 1920s. After World War II, a form of black-and-white TV broadcasting became popular in the United States and Britain, and television sets became commonplace in homes, businesses. During the 1950s, television was the medium for influencing public opinion. In the mid-1960s, color broadcasting was introduced in the US, for many reasons, the storage of television and video programming now occurs on the cloud. At the end of the first decade of the 2000s, digital television transmissions greatly increased in popularity, another development was the move from standard-definition television to high-definition television, which provides a resolution that is substantially higher. HDTV may be transmitted in various formats, 1080p, 1080i, in 2013, 79% of the worlds households owned a television set. Most TV sets sold in the 2000s were flat-panel, mainly LEDs, major manufacturers announced the discontinuation of CRT, DLP, plasma, and even fluorescent-backlit LCDs by the mid-2010s. In the near future, LEDs are gradually expected to be replaced by OLEDs, also, major manufacturers have announced that they will increasingly produce smart TVs in the mid-2010s. Smart TVs with integrated Internet and Web 2.0 functions became the dominant form of television by the late 2010s, Television signals were initially distributed only as terrestrial television using high-powered radio-frequency transmitters to broadcast the signal to individual television receivers. Alternatively television signals are distributed by cable or optical fiber, satellite systems and. Until the early 2000s, these were transmitted as analog signals, a standard television set is composed of multiple internal electronic circuits, including a tuner for receiving and decoding broadcast signals. A visual display device which lacks a tuner is correctly called a video monitor rather than a television, the word television comes from Ancient Greek τῆλε, meaning far, and Latin visio, meaning sight. The Anglicised version of the term is first attested in 1907 and it was. formed in English or borrowed from French télévision. In the 19th century and early 20th century, other. proposals for the name of a technology for sending pictures over distance were telephote. The abbreviation TV is from 1948, the use of the term to mean a television set dates from 1941
30.
ZX Spectrum character set
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The ZX Spectrum character set is the variant of ASCII used in the British Sinclair ZX Spectrum family computers. It is based on ASCII-1967 but the characters ^, and DEL are replaced with ↑, £ and ©. It also differs in its use of the C0 control codes other than the common BS and CR, the ZX Spectrums main set of printable characters and system font are also used by the Jupiter Ace computer. Note that the use of 0x5E as ↑ was also the case in the older 1963 version of ASCII, the £ sign was not mapped to 0x23 as in the British variant of ASCII, allowing both the pound sign and the number sign simultaneously. Beyond 0x7F, the Spectrum character set uses the high-bit range 0x80–0xFF for special purposes, 0x80–0x8F contain the same 2×2 block graphics characters that the ZX80 character set and the ZX81 character set have, also available in the Block Elements Unicode block. However the ZX Spectrums standard character set does not include the ZX80/81 50% dithered 1×2 block graphics characters, code points 0x90–0xA4 contain the originally 21 User-Defined Graphics characters, and 0xA5–0xFF contain BASIC keywords tokenized as single code points. In the 128 BASIC mode introduced later, this was changed to 19 UDG characters ending at 0xA2 followed by the two new tokens SPECTRUM and PLAY, code points 0xC7–0xC9 are the two-character operators <=, >= and <>, similarly tokenized into single code points. These tokens allow a BASIC command like PRINT to be entered with the single keypress P at the beginning of a line which would generate 0xF6, all non-UDG Spectrum characters can be mapped to Unicode. The three non ASCII-1967 characters ↑, £ and © are at U+2191, U+00A3 and U+00A9, the 2×2 block graphics characters are in the Block Elements block at U+2580–U+259F although font support for the latter is not universal. The shape of the UDG characters is mapped to a RAM memory area and is initialized to copies of characters A-U, like all characters in the system font they use an 8×8 pixel grid stored in 8 bytes. Redefining them changes their appearance in subsequent PRINT statements but it does not change any UDG characters already drawn on the screen. The location of a UDG characters definition can be determined with the BASIC function USR with the character as the argument, by default this points to the last 168 bytes of RAM at memory addresses 65368 to 65535 for a 48K Spectrum. The location is pointed to by the system variable UDG which can be found at memory address 23675/6, the definition of the main system font,32 to 127, are referenced by the system variable CHARS which can be found at memory address 23606/7. It is defined as 256 bytes lower than the first byte of the space character, the CHARS value defaults to the value 15360, with the system font at the end of the Spectrums ROM at address 15616 to 16383. Entire alternative fonts can be loaded into RAM and the CHARS variable re-pointed accordingly, in the control codes area, the Spectrum mostly uses proprietary controls, such as INK and PAPER to control foreground and background colour. However, the common BS and CR code points are the same as in ASCII, cursor-down can be simulated with 32 spaces printed with OVER1 and cursor-up 0x0B can be simulated with 32 backspaces. The system ROM has a fault which prevents cursor-right at 0x09 from working, control code 0x0E is used to indicate that a floating-point number follows, to accelerate text processing. In a Sinclair BASIC program numeric constants are stored as ASCII followed by a 0x0E byte, when listing a BASIC program only the ASCII part is used but at runtime only the binary representation is used
31.
Image resolution
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Image resolution is the detail an image holds. The term applies to digital images, film images. Higher resolution means more image detail, image resolution can be measured in various ways. Resolution quantifies how close lines can be to other and still be visibly resolved. Resolution units can be tied to physical sizes, to the size of a picture. Line pairs are used instead of lines, a line pair comprises a dark line. A line is either a line or a light line. A resolution of 10 lines per millimeter means 5 dark lines alternating with 5 light lines, photographic lens and film resolution are most often quoted in line pairs per millimeter. The resolution of digital cameras can be described in different ways. Resolution is the capability of the sensor to observe or measure the smallest object clearly with distinct boundaries, there is a difference between the resolution and a pixel. A pixel is actually a unit of the digital Resolution depends upon the size of the pixel, usually, with any given lens setting, the smaller the size of the pixel, the higher the resolution will be and the clearer the object in the image will be. Images having smaller pixel sizes might consist of more pixels, the number of pixels correlates to the amount of information within the image. An image of N pixels height by M pixels wide can have any less than N lines per picture height. Other conventions include describing pixels per unit or pixels per area unit. None of these pixel resolutions are true resolutions, but they are referred to as such. Below is an illustration of how the image might appear at different pixel resolutions. An image that is 2048 pixels in width and 1536 pixels in height has a total of 2048×1536 =3,145,728 pixels or 3.1 megapixels, one could refer to it as 2048 by 1536 or a 3. 1-megapixel image. Or, you can think of it as a low quality image if printed at about 28.5 inches wide
32.
Bitmap
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In computing, a bitmap is a mapping from some domain to bits, that is, values which are zero or one. It is also called a bit array or bitmap index, in computer graphics, when the domain is a rectangle a bitmap gives a way to store a binary image, that is, an image in which each pixel is either black or white. The more general term refers to a map of pixels. Often bitmap is used for this as well, in some contexts, the term bitmap implies one bit per pixel, while pixmap is used for images with multiple bits per pixel. A bitmap is a type of organization or image file format used to store digital images. The term bitmap comes from the computer programming terminology, meaning just a map of bits, now, along with pixmap, it commonly refers to the similar concept of a spatially mapped array of pixels. Raster images in general may be referred to as bitmaps or pixmaps, whether synthetic or photographic, besides BMP, other file formats that store literal bitmaps include InterLeaved Bitmap, Portable Bitmap, X Bitmap, and Wireless Application Protocol Bitmap. Similarly, most other file formats, such as JPEG, TIFF, PNG, and GIF, also store bitmap images. In typical uncompressed bitmaps, image pixels are stored with a color depth of 1,4,8,16,24,32,48. Pixels of 8 bits and fewer can represent either grayscale or indexed color. An alpha channel may be stored in a bitmap, where it is similar to a grayscale bitmap, or in a fourth channel that, for example. The bits representing the bitmap pixels may be packed or unpacked, depending on the color depth, a pixel in the picture will occupy at least n/8 bytes, where n is the bit depth. In the formula above, header size and color palette size, due to effects of row padding to align each row start to a storage unit boundary such as a word, additional bytes may be needed. They called these device-independent bitmaps or DIBs, and the format for them is called DIB file format or BMP file format. According to Microsoft support, A device-independent bitmap is a used to define device-independent bitmaps in various color resolutions. The main purpose of DIBs is to allow bitmaps to be moved from one device to another, a DIB is an external format, in contrast to a device-dependent bitmap, which appears in the system as a bitmap object. A DIB is normally transported in metafiles, BMP files, here, device independent refers to the format, or storage arrangement, and should not be confused with device-independent color. The X Window System uses a similar XBM format for black-and-white images, numerous other uncompressed bitmap file formats are in use, though most not widely
33.
Patent
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A patent is a set of exclusive rights granted by a sovereign state to an inventor or assignee for a limited period of time in exchange for detailed public disclosure of an invention. An invention is a solution to a technological problem and is a product or a process. Patents are a form of intellectual property, the procedure for granting patents, requirements placed on the patentee, and the extent of the exclusive rights vary widely between countries according to national laws and international agreements. Typically, however, a patent application must include one or more claims that define the invention. A patent may include many claims, each of which defines a specific property right and these claims must meet relevant patentability requirements, such as novelty, usefulness, and non-obviousness. Nevertheless, there are variations on what is patentable subject matter from country to country, the word patent originates from the Latin patere, which means to lay open. More directly, it is a version of the term letters patent. Similar grants included land patents, which were land grants by early state governments in the USA, and printing patents, a precursor of modern copyright. In modern usage, the term patent usually refers to the granted to anyone who invents any new, useful. The additional qualification utility patent is used to distinguish the primary meaning from these other types of patents. Particular species of patents for inventions include biological patents, business method patents, chemical patents, the period of protection was 10 years. These were mostly in the field of glass making, as Venetians emigrated, they sought similar patent protection in their new homes. This led to the diffusion of patent systems to other countries, by the 16th century, the English Crown would habitually abuse the granting of letters patent for monopolies. After public outcry, King James I of England was forced to revoke all existing monopolies, the Statute became the foundation for later developments in patent law in England and elsewhere. Important developments in patent law emerged during the 18th century through a process of judicial interpretation of the law. During the reign of Queen Anne, patent applications were required to supply a complete specification of the principles of operation of the invention for public access. Influenced by the philosophy of John Locke, the granting of patents began to be viewed as a form of property right. The English legal system became the foundation for patent law in countries with a common law heritage, including the United States, New Zealand, in the Thirteen Colonies, inventors could obtain patents through petition to a given colonys legislature
34.
Attribute clash
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The effect was also noticeable on MSX software and in some Commodore 64 titles. Workarounds to prevent this limit from becoming apparent have since considered an element of Spectrum programmer culture. This problem also happens with the modes of the Color Computer and Dragon. The Super NES allowed 16 colours per tile but 256 per screen, rather than limit the colour palette to conserve memory, Sinclairs design stored pixel bitmap and colour information in separate areas of memory. While the bitmap specified the state of individual pixels, the colour information corresponded to the text character matrix—24 rows of 32 columns—with one byte per 8x8 pixel character cell. This byte encoded two 3-bit values, known as INK and PAPER after the BASIC instructions used to define the colour values and this scheme provided 15 different colours, the eight combinations of red, green and blue at two brightness levels. Thus, each 8x8 pixel block could only contain 2 colours from the 15 available, trying to add a third colour in an 8x8 pixel area would result in the three colours being reduced to two by the ZX Spectrum. The architecture was retained to prevent loss of backward compatibility, attributes were used by a variety of other computers and consoles, including the Commodore 64, the MSX and NES, although the size of the attribute blocks and the number of colours per block varied. However, with the use of sprites and scrolling, attribute clash could be avoided. Giving a similar but less severe effect than with the Spectrum. The MSX1 did not have just one single colour attribute byte available for a whole 8x8 pixel area, as was the case with the Sinclair Spectrum, but eight, one attribute byte for each 8×1 pixel area. Thus, while the Spectrum was limited to one pair for a square area of 8x8 pixels. In addition MSX1 could use sprites which were not bound to any attribute clash problems, in practice this technical advantage often did not help MSX1 systems to produce better pictures. To ease conversion, the developers simply copied the single attribute byte value of the Spectrum to all eight corresponding attribute bytes of the MSX1. In contrast, Japanese MSX1 games did use all the capabilities of MSX1, to avoid attribute clash, static graphic displays had to be constructed with care. Finely-detailed colour graphics were impossible, as colour could only be applied in 8×8 pixel blocks, careful design could achieve impressive results, as could synchronising colour changes to the refresh rate of the display—usually a television set. However, animated displays were more difficult—a distinct drawback in a machine whose primary use was playing video games, if just one pixel in an 8×8 block was recoloured because a moving part of the display touched it, the entire block would change colour. Thus detailed moving graphics caused large ugly fringes of rapidly changing colours to follow them around, early software simply ignored the problem
35.
Sprite (computer graphics)
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In computer graphics, a sprite is a two-dimensional bitmap that is integrated into a larger scene. Originally sprites referred to independent objects that are composited together, by hardware and this occurs as each scan line is prepared for the video output device, such as a CRT, without involvement of the main CPU and without the need for a full-screen frame buffer. Sprites can be positioned or altered by setting attributes used during the composition process. Examples of systems with hardware sprites include the Atari 8-bit family, Commodore 64, Nintendo Entertainment System, Sega Genesis, the act of creating sprites is a form of pixel art. It is sometimes referred to as spriting, especially in the hobbyist community, the use of sprites originated with arcade games. The first video game to represent player characters as human player images was Taitos Basketball, Signetics devised the first video/graphics processors capable of generating sprite graphics for home systems. The Signetics 2636 video processors were first used in the 1976 Radofin 1292 Advanced Programmable Video System, the Atari VCS, released in 1977, features a hardware sprite implementation where five graphical objects can be moved independently of the game playfield. The term sprite was not in use at the time, the VCSs sprites are called movable objects in the programming manual, further identified as two players, two missiles, and one ball. These each consist of a row of pixels that are displayed on a scan line. To produce a shape, the sprites single-row bitmap is altered by software from one scanline to the next. Each is the height of the display—a long, thin strip. DMA from a table in memory automatically sets the graphics pattern registers for each scan line, hardware registers control the horizontal position of each player and missile. Vertical motion is achieved by moving the data within a player or missiles strip. The feature was called player/missile graphics by Atari, the Namco Galaxian arcade system board, for the 1979 arcade game Galaxian, featured animated, multi-colored sprites. According to Steve Golson from General Computer Corporation, the stamp was used instead of sprite at the time. The Elektor TV Games Computer was a microcomputer capable of generating sprite graphics. The term sprite was first used in the sense by one of the definers of the Texas Instruments 9918 video display processor. By this time, sprites had advanced to the point where complete two-dimensional shapes could be moved around the screen horizontally and vertically with minimal software overhead, the CPU would instruct the external chips to fetch source images and integrate them into the main screen using direct memory access channels
36.
ZX Spectrum software
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The ZX Spectrum software library currently consists of more than 24,000 titles. Because most British home computer owners used tape instead of disk storage into the mid-1980s, the software was encoded on tape as a sequence of pulses that may sound similar to the sounds of a modern-day modem. Since ZX Spectrum had only a tape interface, data was recorded using an unusually simple and very reliable modulation, similar to pulse-width modulation. Pulses of different widths represent 0s and 1s, a zero is represented by a ~244 μs pulse followed by a gap of the same duration for a total ~489 μs, one is twice as long, totaling ~977 μs. This allows for 1023 ones or 2047 zeros to be recorded per second, assuming an even proportion of each, the resulting average speed was ~1535 bit/s. Higher speeds were possible using custom machine code instead of the ROM routines. Naturally, a standard 48K program would take about 5 minutes to load,49152 bytes ×8 =393216 bits,393216 bits /1535 baud ≈256 seconds =4,16 minutes. In reality, however, a 48K program usually took between 3–4 minutes to load, and 128K programs could take up to 11,23 minutes to load. Experienced users could often tell the type of a file, e. g. file header, screen image or main block of code, the standard method of storing files on tape used pilot signals, headers, and data blocks. Pilot signals are used to calibrate the system to the speed of the tape, or Character array, <filename> for an ASCII-encoded file. Pilot signals are represented with a thick stripe size, on header and data blocks. One common cause was the use of a copy from a tape recorder with a different head alignment to the one being used. This could sometimes be fixed by pressing on the top of the player during loading, or wedging the cassette with pieces of folded paper, a more reliable solution was to realign the head, which was easily accessible on a number of tape players, with a small screwdriver. Typical settings for loading were ¾ volume, 100% treble, 0% bass, audio filters like loudness and Dolby Noise Reduction had to be disabled, and it was not recommended to use a Hi-Fi player to load programs. There were some tape recorders built specially for use, such as the Timex Computer 2010 Tape Recorder or Grundig CR100 Data Recorder. The ZX Spectrum Plus 2 and 2A models are fashioned after an Amstrad CPC464 and it is possible to alter the colours between which the border alternates during loading, and/or to use more than two colours, in order to obtain more flashy visual effects during the loading process. This relied rather too much on using the same size television. One very interesting kind of software was copiers, best known were the Lerm suite produced by Lerm Software and Trans Express by Romantic Robot
37.
Expansion card
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An expansion bus is a computer bus which moves information between the internal hardware of a computer system and peripheral devices. It is a collection of wires and protocols that allows for the expansion of a computer, even vacuum-tube based computers had modular construction, but individual functions for peripheral devices filled a cabinet, not just a printed circuit board. Processor, memory and I/O cards became feasible with the development of integrated circuits, minicomputers, starting with the PDP-8, were made of multiple cards, all powered by and communicating through a passive backplane. The first commercial microcomputer to feature expansion slots was the Micral N, proprietary bus implementations for systems such as the Apple II co-existed with multi-manufacturer standards. IBM introduced what would retroactively be called the Industry Standard Architecture bus with the IBM PC in 1981, the IBM XT, introduced in 1983, used the same bus. The 8-bit PC and XT bus was extended with the introduction of the IBM AT and this used a second connector for extending the address and data bus over the XT, but was backward compatible, 8-bit cards were still usable in the AT 16-bit slots. Industry Standard Architecture became the designation for the IBM AT bus after other types were developed. IBMs MCA bus, developed for the PS/2 in 1987, was a competitor to ISA, also their design, but fell out of favor due to the ISAs industry-wide acceptance and IBMs licensing of MCA. EISA, the 32-bit extended version of ISA championed by Compaq, was used on some PC motherboards until 1997, proprietary local buses and then the VESA Local Bus Standard, were late 1980s expansion buses that were tied but not exclusive to the 80386 and 80486 CPU bus. The PC/104 bus is a bus that copies the ISA bus. Intel launched their PCI bus chipsets along with the P5-based Pentium CPUs in 1993, the PCI bus was introduced in 1991 as replacement for ISA. The standard is found on PC motherboards to this day, the PCI standard supports bus bridging, as many as ten daisy chained PCI buses have been tested. Cardbus, using the PCMCIA connector, is a PCI format that attaches peripherals to the Host PCI Bus via PCI to PCI Bridge, cardbus is being supplanted by ExpressCard format. Intel introduced the AGP bus in 1997 as a video acceleration solution. AGP devices are attached to the PCI bus over a PCI-to-PCI bridge. Though termed a bus, AGP usually supports only a card at a time. From 2005 PCI-Express has been replacing both PCI and AGP and this standard, approved in 2004, implements the logical PCI protocol over a serial communication interface. PC/104 or Mini PCI are often added for expansion on small form factor boards such as Mini-ITX, for their 1000 EX and 1000 HX models, Tandy Computer designed the PLUS expansion interface, an adaptation of the XT-bus supporting cards of a smaller form factor
38.
Edge connector
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An edge connector is the portion of a printed circuit board consisting of traces leading to the edge of the board that are intended to plug into a matching socket. The edge connector is a device because it only requires a single discrete female connector. They are commonly used in computers for expansion slots for cards, such as PCI, PCI Express. Edge connector sockets consist of a plastic box open on one side, connectors are often keyed to ensure the correct polarity, and may contain bumps or notches both for polarity and to ensure that the wrong type of device is not inserted. The sockets width is chosen to fit to the thickness of the connecting PCB, the opposite side of the socket is often an insulation-piercing connector which is clamped onto a ribbon cable. Alternatively, the side may be soldered to a motherboard or daughtercard. Edge connectors are used in personal computers for connecting expansion cards. Example expansion peripheral technologies which use edge connectors include PCI, PCI Express, Slot 1 and Slot A also used edge connectors, the processor being mounted on a card with an edge connector, instead of directly to the motherboard as before and since. IBM PCs used edge connector sockets attached to cables to connect 5.25 floppy disk drives. 3.5 drives use a pin connector instead, video game cartridges typically take the form of a PCB with an edge connector, the socket is located within the console itself
39.
Cassette deck
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A cassette deck is a type of tape machine for playing and recording audio compact cassettes. Although the two terms used interchangeably, a recorder is typically thought of as a low-fidelity portable device. The first consumer tape recorder to employ a tape reel permanently housed in a removable cartridge was the RCA tape cartridge. The tape width was 1⁄8 inch and tape speed was 1.875 inches per second, giving a decidedly non Hi-Fi frequency response, early recorders were intended for dictation and journalists, and were typically hand-held battery-powered devices with built-in microphones and automatic gain control on recording. Tape recorder audio-quality had improved by the mid-1970s, and a deck with manual level controls. Cassettes became extremely popular for automotive and other portable music applications, although pre-recorded cassettes were widely available, many users would combine songs from their vinyl records or cassettes to make a new custom mixtape cassette. In 1970, the Advent Corporation combined Dolby B noise reduction system with chromium dioxide tape to create the Advent Model 200, Dolby B uses volume companding of high frequencies to boost low-level treble information by up to 9 dB, reducing them on playback. CrO2 used different bias and equalization settings to reduce the noise level. Together these allowed a flat frequency response beyond 15 kHz for the first time. Both featured an unusual single VU meter which could be switched between or for both channels, most manufacturers adopted a standard top-loading format with piano key controls, dual VU meters, and slider level controls. Mechanical controls were replaced with push buttons controlling solenoid mechanical actuators. Some models could search and count gaps between songs, Cassette decks soon came into widespread use and were designed variously for professional applications, home audio systems, and for mobile use in cars, as well as portable recorders. From the mid-1970s to the late 1990s the cassette deck was the music source for the automobile. A major boost to the cassettes popularity came with the release of the Sony Walkman personal cassette player in 1979, although the vast majority of such players eventually sold were not Sony products, the name Walkman has become synonymous with this type of device. Cassette decks were eventually manufactured by almost every well known brand in home audio, Cassette decks reached their pinnacle of performance and complexity by the mid-1980s. Cassette decks from companies such as Nakamichi, Revox, and Tandberg incorporated advanced features such as multiple tape heads, auto-reversing decks became popular and were standard on most factory installed automobile decks. Three-head technology uses separate heads for recording and playback and this allows different record and playback head gaps to be used. A narrower head gap is optimal for playback than for recording, separate record and playback heads also allow off-the-tape monitoring during recording, permitting immediate verification of the recording quality
40.
Line level
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Line level is the specified strength of an audio signal used to transmit analog sound between audio components such as CD and DVD players, television sets, audio amplifiers, and mixing consoles. As opposed to line level, there are weaker audio signals, such as those from microphones and instrument pickups, the strength of these various signals does not necessarily refer to the output voltage of the source device, it also depends on its output impedance and output power capability. Consumer electronic devices concerned with audio often have a labeled line in and/or line out. Line out provides a signal output and line in receives a signal input. Professional equipment commonly uses balanced connections on 6.35 mm TRS phone jacks or XLR connectors, professional equipment may also use unbalanced connections with TS phone jacks. A line level describes a lines nominal signal level as a ratio, expressed in decibels, the nominal level and the reference voltage against which it is expressed depend on the line level being used. While the nominal levels themselves vary, only two reference voltages are common, decibel volts for consumer applications, and decibels unloaded for professional applications, the decibel volt reference voltage is 1 VRMS =0 dBV. The decibel unloaded reference voltage,0 dBu, is the AC voltage required to produce 1 mW of power across a 600 Ω impedance. This awkward unit is a holdover from the early telephone standards, which used 600 Ω sources and loads, modern audio equipment does not use 600 Ω matched loads, hence dBm unloaded. The most common nominal level for consumer audio equipment is −10 dBV, and the most common nominal level for professional equipment is +4 dBu. Expressed in absolute terms, a signal at −10 dBV is equivalent to a wave signal with a peak amplitude of approximately 0.447 volts. A signal at +4 dBu is equivalent to a wave signal with a peak amplitude of approximately 1.736 volts. Peak-to-peak amplitude refers to the voltage swing of a signal. For instance, a signal with an amplitude of ±0.5 V has a p-p amplitude of 1.0 V. The line level signal is a current signal without a DC offset. Instead, line level circuits use the impedance bridging principle, in which a low impedance output drives a high impedance input, a typical line out connection has an output impedance from 100 to 600 Ω, with lower values being more common in newer equipment. Line inputs present a higher impedance, typically 10 kΩ or more. Most of the voltage asserted by the output appears across the input impedance, the line input acts similarly to a high impedance voltmeter or oscilloscope input, measuring the voltage asserted by the output while drawing minimal current from the source
41.
Dundee
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Dundee, officially the City of Dundee, is Scotlands fourth-largest city and the 51st-most-populous built-up area in the United Kingdom. The mid-year population estimate for 2015 was 148,210 which gave Dundee a population density of 2, 477/km2 or 6, 420/sq mi and it lies within the eastern central Lowlands on the north bank of the Firth of Tay, which feeds into the North Sea. Under the name of Dundee City, it one of the 32 council areas used for local government in Scotland. Historically part of Angus, the city developed into a burgh in the late 12th century, rapid expansion was brought on by the Industrial Revolution, particularly in the 19th century when Dundee was the centre of the global jute industry. This, along with its major industries gave Dundee its epithet as the city of jute, jam. Biomedical and technological industries have arrived since the 1980s, and the city now accounts for 10% of the United Kingdoms digital-entertainment industry, Dundee has two universities — the University of Dundee and the Abertay University. In 2014 Dundee was recognised by the United Nations as the UKs first UNESCO City of Design for its contributions to fields including medical research, comics. A unique feature of Dundee is that its two football clubs Dundee United and Dundee F. C. have stadiums all but adjacent to each other. With the decline of industry, the city has adopted a plan to regenerate. The name Dundee is made up of two parts, the common Celtic place-name element dun, meaning fort, and a part that may derive from a Celtic element, cognate with the Gaelic dè. The situation of the town and its promotion by Earl David as a trading centre led to a period of prosperity, the earldom was passed down to Davids descendants, amongst whom was John Balliol. The town became a Royal Burgh on Johns coronation as king in 1292, the town and its castle were occupied by English forces for several years during the First War of Independence and recaptured by Robert the Bruce in early 1312. The original Burghal charters were lost during the occupation and subsequently renewed by Bruce in 1327, the burgh suffered considerably during the conflict known as the Rough Wooing of 1543 to 1550, and was occupied by the English forces of Andrew Dudley from 1547. In 1548, unable to defend the town against an advancing Scottish force, in 1645, during the Wars of the Three Kingdoms, Dundee was again besieged, this time by the Royalist Marquess of Montrose. The town was destroyed by Parliamentarian forces led by George Monck in 1651. The town played a role in the establishment of the Jacobite cause when John Graham of Claverhouse. The town was held by the Jacobites in the 1715–16 rising, many in Scotland, including many in Dundee, regarded him as the rightful king. The economy of mediaeval Dundee centred on the export of raw wool, expansion of the whaling industry was triggered by the second Bounty Act, introduced in 1750 to increase Britains maritime and naval skill base
42.
Timex Sinclair
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The choice of partnership was natural, as Timex was already the main contractor for manufacture of Sinclairs ZX81 and ZX Spectrum computers at its Scottish plant in Dundee. It was Timex of Portugal, though, that took on the R&D, although both Timex of Scotland and Timex of Portugal were full subsidiaries of Timex, internal rivalry, whether unintended or purported, meant there was little sharing between the two plants. Timex of Portugal also sold the Timex Sinclair models in Portugal, Timex Sinclair released four computers, all of them based on Sinclair Researchs existing machines. Its European sibling, the TC2068, featured improved compatibility with the ZX Spectrum, tC2048, a ZX Spectrum-based machine with a TS 2068-like keyboard. The Timex Sinclair 1000 was introduced in July 1982, with Timex Sinclair touting it as the first home computer to cost under $100 in the U. S. market. In spite of the flaws in the versions, half a million units were sold in the first six months alone. Timex Corporation withdrew from the U. S. home computer market in February 1984 but Timex of Portugal continued to manufacture, sell and develop hardware in Portugal, tC3256 was the next proposed computer. It was designed as the generation of Timex Computer Technology. Timex FDD or FDD3000, a Z80-based CP/M-compatible computer, most people only know it as a floppy disk drive controller but in fact, it is a computer without graphics circuitry. As a CP/M system, using the Timex Terminal 3000, a terminal keyboard, Timex Sinclair produced the following peripherals for the Timex computer line, TS1016 - Timex 16K RAM Pack for use on a TS1000. TS1050 - Not a real peripheral, but a suitcase to carry TS1000, tapes, to export the Timex Computer to Poland, Timex of Portugal had to be paid in goods. It chose to import the Neptun 15612 green monochrome monitor, based on the Vela TV receiver, it proved very popular in Portugal and was frequently sold in bundles with the TC computers
43.
Steve Vickers (computer scientist)
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Steve Vickers is a British mathematician and computer scientist. In the early 1980s, he wrote ROM firmware and manuals for three computers, the Sinclair ZX81 and ZX Spectrum and the Jupiter Ace. The latter was produced by Jupiter Cantab, a short-lived company Vickers formed together with Richard Altwasser, after the two had left Sinclair Research. Since the late 1980s, Vickers has been an academic in the field of geometric logic and his book Topology via Logic has been influential over a range of fields. He is currently a Senior Lecturer at the University of Birmingham, Vickers graduated from Kings College, Cambridge with a degree in mathematics and completed a PhD at Leeds University, also in mathematics. In 1980 he started working for Nine Tiles, which had written the Sinclair BASIC for the ZX80. He was responsible for the adaptation of the 4K ZX80 ROM into the 8K ROM used in the ZX81 and he then wrote most of the ZX Spectrum ROM, and assisted with the user documentation. Vickers left in 1982 to form Rainbow Computing Co. with Richard Altwasser, the company became Jupiter Cantab and they were together responsible for the development of the commercially unsuccessful Jupiter ACE, a competitor to the similar Sinclair ZX Spectrum. Vickers main interest lies within geometric logic and his book Topology via Logic introduces topology from the point of view of some computational insights developed by Samson Abramsky and Mike Smyth. However, the book was written in the language of classical mathematics, much of his subsequent work has been in case studies to show that, with suitable techniques, it was indeed possible to do useful mathematics geometrically. In particular, a notion of transformation of points to spaces gives a natural fibrewise treatment of topological bundles. Steven Vickers, An induction principle for consequence in arithmetic universes, Journal of Pure and Applied Algebra 216, ISSN 0022-4049, Steven Vickers, Cosheaves and connectedness in formal topology, Annals of Pure and Applied Logic, ISSN 0168-0072,2009. Steven Vickers, A localic theory of lower and upper integrals, Mathematical Logic Quarterly,54, palmgren, Erik and Vickers, Steven, Partial Horn logic and cartesian categories, Annals of Pure and Applied Logic,145, pp. 314–353, ISSN 0168-0072,2007. Steven Vickers, Localic completion of generalized metric spaces I, Theory and Applications of Categories, ISSN 1201-561X,14, Steven Vickers, Localic completion of generalized metric spaces II, Powerlocales, Journal of Logic and Analysis, ISSN 1759-9008,1, pp. 1–48,2009. Steven Vickers, The double powerlocale and exponentiation, a study in geometric logic, Theoretical Computer Science, ISSN 0304-3975. Steven Vickers, Topical Categories of Domains, in Winskel, Proceedings of the CLICS workshop, Aarhus, Computer Science Department, Vickers, S. J. Toposes pour les vraiment nuls, in Edalat, A. and Jourdan, S. and McCusker, G. Advances in Theory and Formal Methods of Computing 1996, ISBN 1-86094-031-5, Imperial College Press, London, Vickers, S. J. Toposes pour les nuls, Techreport Doc96/4, Department of Computing, Imperial College, London. Broda, K. and Eisenbach, S. and Khoshnevisan, H. and Vickers, reasoned Programming, ISBN 0-13-098831-6, Prentice Hall, International Series in Computer Science,1994
44.
Chiclet keyboard
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A perforated bezel fills the gaps between the keys. The term has changed meaning in recent years, during the first home computer boom of the 1980s, a chiclet keyboard was synonymous with cheap quality and a poor user experience. The term first appeared during the computer era of the late 1970s to mid-1980s. The TRS-80 Color Computer, TRS-80 MC-10, and Timex Sinclair 2068 were all described as having chiclet keys and this style of keyboard was met with poor reception. John Dvorak wrote that it was associated with $99 el cheapo computers and its quality was such that an amazed Tandy executive, whose company had previously released a computer with a similarly unpopular keyboard, asked How could IBM have made that mistake with the PCjr. Two decades later the term instead describes low-profile, low-travel scissor keyboards with simplified, sony was the first modern laptop manufacturer to make use of this keyboard style with the release of the VAIO X505 in 2004. The underlying technology used by such keyboards varies considerably, in some versions of the chiclet keyboard, the bottom three layers are essentially the same as those in the membrane keyboard. In both cases, a keypress is registered when the top layer is forced through a hole to touch the bottom layer, for every key, the conductive traces on the bottom layer are normally separated by a non-conductive gap. Electric current cannot flow between them, the switch is open, when pushed down, conductive material on the underside of the top layer bridges the gap between those traces, the switch is closed, current can flow, and a keypress is registered. Unlike the membrane keyboard, where the user presses directly onto the top membrane layer, with some key designs, the user pushes the key, and under sufficient pressure the thin sides of the rubber key suddenly collapse. In other designs — such as seen in the diagram — the deliberate weak point is where the key joins the rest of the sheet. The effect is similar in both cases and this collapse allows the solid rubber center to move downwards, forcing the top membrane layer against the bottom layer, and completing the circuit. The sudden collapse of the keyboard provides a greater tactile feedback to the user than a simple flat membrane keyboard. Other versions of the chiclet keyboard omit the upper membrane and hole/spacer layers, when the key is pushed, the conductive underside makes contact with the traces on the bottom layer, and bridges the gap between them, thus completing the circuit. Grooves between hollow domes on the underside permit air to flow out of a dome when a key is pressed, the dome switch keyboards used with a large proportion of modern PCs are technically similar to chiclet keyboards. The rubber keys are replaced with rubber domes, and hard plastic keytops rest on top of these, because the keytops are wider than the rubber domes the keytops are not separated but align almost perfectly with only a minimal gap in between each other. All of the computers listed hail from the home computer era
