1.
Plus fours
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Plus fours are breeches or trousers that extend 4 inches below the knee. As they allow more freedom of movement than knickerbockers, they have been associated with sporting attire from the 1860s and onward. They are often seen on golf courses, and frequently worn with socks, silk neckties. Some plus fours came as complete suits and they became associated with bicycle fashion in the 1950s and 60s in Great Britain. They were later brought back to prominence by the professional golfer Payne Stewart who wore them on the PGA Tour, in 2008, plus fours were featured in André Benjamins Benjamin Bixby clothing line, which was based on clothing worn by Ivy League athletes in the 1930s. Less known are plus twos, plus sixes, and plus eights, of similar definitions, in fiction, Tintin, the comic book character from The Adventures of Tintin, famously wears plus fours
2.
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
3.
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
4.
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
5.
MOS Technology
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MOS Technology, Inc. also known as CSG, was a semiconductor design and fabrication company based in Norristown, Pennsylvania, in the United States. It is most famous for its 6502 microprocessor and various designs for Commodore Internationals range of home computers, MOS Technology, Inc. was originally started in 1969 by Allen-Bradley to provide a second source for electronic calculators and their chips designed by Texas Instruments. Many early chip companies were wiped out in the aftermath, those that survived did so by finding other chips to produce, MOS became a supplier to Atari, producing a custom single-chip Pong system. Several of the designers of the Motorola 6800 left Motorola shortly after its release, at the time there was no such thing as a design-only firm, so they had to join a chip-building company to produce their new CPU. MOS was a firm with good credentials in the right area. The team of four design engineers was headed by Chuck Peddle, at MOS they set about building a new CPU that would outperform the 6800 while being similar to it in purpose. The resulting 6501 design was similar to the 6800, but by using several simplifications in the design. In addition to a design, MOS had a secret weapon. Masks are the drawings of the chip that are photo-reduced to make the pattern from which chips are made—a process similar to photocopying. All masks end up with flaws, both as a result of problems in the chip itself, as well as side effects from the photo-reduction process. When a chip is made with this there is a chance that some of these flaws will end up expressed on the chip. If too many of them are expressed, that particular chip will not work, so companies simply built chips with known-bad masks, and threw away broken chips. In the 1970s, this meant throwing away 70 percent or more of the completed chips. The price of a chip is largely defined by the yield, MOSs engineers had learned the trick of fixing their masks after they were made. This allowed them to correct the flaws in a series of small fixes. This meant that not only were its designs faster, they cost much less as well, when the 6501 was announced, Motorola launched a lawsuit almost immediately. That was enough to allow Motorola to sue, sales of the 6501 basically stopped, and the lawsuit would drag on for many years before MOS was eventually forced to pay $200,000 USD in fines. In the meantime MOS had started selling the 6502, a capable of operating at 1 MHz in September 1975 for a mere $25 USD
6.
MOS Technology 6510
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The MOS Technology 6510 is an 8-bit microprocessor designed by MOS Technology, Inc. and is a modified form of the very successful 6502. The primary change from the 6502 was the addition of an 8-bit general purpose I/O port, in addition, the address bus could be made tristate. The 6510 was only used in the Commodore 64 home computer. In 1985, MOS produced the 8500, an HMOS version of the 6510, other than the process change, it is virtually identical to the NMOS version of the 6510. The 8500 was originally designed for use in the modernised C64, however, in 1985, limited quantities of 8500s were found on older NMOS-based C64s. It finally made its debut in 1987, appearing in a motherboard using the new 85xx HMOS chipset. The 7501/8501 variant of the 6510 was introduced in 1984 and it was used in Commodores C16, C116 and Plus/4 home computers, where its I/O port controlled not only the Datasette but also the CBM Bus interface. The main difference between 7501 and 8501 CPUs is that they were manufactured with different technologies,7501 was manufactured with HMOS-1 and 8501 with HMOS-2, the NMI signal are not available for MOS7501 and MOS8501. The 2 MHz-capable 8502 variant was used in the Commodore 128, all these CPUs are opcode compatible. The Commodore 1551 disk drive used the 6510T, a version of the 6510 with eight I/O lines, the NMI and RDY signals are not available. Interrupts in 65xx processors MOS6510 datasheet MOS6510 datasheet MOS6510 datasheet Marat Fayzullins emulator page A web server using a MOS6510 computer aka C64 unmodified
7.
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
8.
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
9.
MOS Technology TED
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The 7360 Text Editing Device was an integrated circuit made by MOS Technology, Inc. It was a chip that also contained sound generation hardware, DRAM refresh circuitry, interval timers. It was designed for the Commodore Plus/4 and 16, packaging consisted of a JEDEC-standard 48-pin DIP. The video capabilities provided by the TED were largely a subset of those in the VIC-II, however, the TED lacked the sprite capabilities of the VIC-II, and so game animation had to be done with programmable characters like on the VIC-20. This tended to restrict the graphics of C16/Plus 4 games versus the C64, the TED did include two features that the VIC-II lacked, luminance control and blinking text. Fifteen of its 16 colors could be assigned one of 8 luminance values, the full palette of 121 colors is shown below. The TED featured a tone generator that produced two channels of audio. The first channel produced a wave, and the second could produce either a square wave or white noise. This tone generator was designed for applications, and did not provide the extensive sound features found in the SID chip. The TED includes three 16-bit interval timers, which consist of down counters operating at the clock frequency. They can generate IRQs on underflow, the chip also contains an I/O port, which is used on the Plus/4 and 16 to scan the keyboard and joystick. In addition, it handles bank switching, used by the system to maximize the amount of RAM available to Commodore BASIC. An undesirable feature of the chip is its tendency to destroy itself though overheating. To preserve a computer which employs this chip in working order, talking to TED, The MOS 7360/8360 Text Display ICs TED data sheet
10.
Commodore International
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Commodore International was a North American home computer and electronics manufacturer. Commodore International, along with its subsidiary Commodore Business Machines, participated in the development of the computer industry in the 1970s and 1980s. The company developed and marketed one of the worlds best-selling desktop computers, the company that would become Commodore Business Machines, Inc. was founded in 1954 in Toronto as the Commodore Portable Typewriter Company by Polish immigrant and Auschwitz survivor Jack Tramiel. He moved to Toronto to start production, by the late 1950s a wave of Japanese machines forced most North American typewriter companies to cease business, but Tramiel instead turned to adding machines. In 1955, the company was incorporated as Commodore Business Machines. In 1962, Commodore went public on the New York Stock Exchange, in the late 1960s, history repeated itself when Japanese firms started producing and exporting adding machines. The companys main investor and chairman, Irving Gould, suggested that Tramiel travel to Japan to understand how to compete, instead, he returned with the new idea to produce electronic calculators, which were just coming on the market. Commodore soon had a profitable calculator line and was one of the popular brands in the early 1970s. However, in 1975, Texas Instruments, the supplier of calculator parts, entered the market directly. Commodore obtained an infusion of cash from Gould, which Tramiel used beginning in 1976 to purchase several second-source chip suppliers, including MOS Technology, Inc. in order to assure his supply. He agreed to buy MOS, which was having troubles of its own, through the 1970s, Commodore also produced numerous peripherals and consumer electronic products such as the Chessmate, a chess computer based around a MOS6504 chip, released in 1978. In December 2007 when Tramiel was visiting the Computer History Museum in Mountain View, California, for the 25th anniversary of the Commodore 64 and he said, I wanted to call my company General, but theres so many Generals in the U. S. Then I went to Admiral, but that was taken, so I wind up in Berlin, Germany, with my wife, and we were in a cab, and the cab made a short stop, and in front of us was an Opel Commodore. Tramiel gave this account in interviews, but Opels Commodore didnt debut until 1967. Once Chuck Peddle had taken over engineering at Commodore, he convinced Jack Tramiel that calculators were already a dead end, from PETs 1977 debut, Commodore would be a computer company. The operational headquarters, where research and development of new products occurred, retained the name Commodore Business Machines, in 1980 Commodore launched production for the European market in Braunschweig. By 1980 Commodore was one of the three largest microcomputer companies, and the largest in the Common Market and this was addressed with the introduction of the VIC-20 in 1981, which was introduced at a cost of US$299 and sold in retail stores. Commodore took out ads featuring William Shatner asking consumers Why buy just a video game
11.
Productivity software
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Its names arose from the fact that it increases productivity, especially of individual office workers, from typists to knowledge workers, although its scope is now wider than that. Office suites, which word processing, spreadsheet, and relational database programs to the desktop in the 1980s, are the core example of productivity software. Some 78% of middle-skill occupations now require the use of productivity software, in the 2010s, productivity software has become even more consumerized than it already was, as computing becomes ever more integrated into daily personal life. Productivity software traditionally run directly on a computer, for example, Commodore Plus/4 model of computer contained in ROM four applications of productivity software. Productivity software is one of the people use personal computers. Productivity software help the professional or common user to enhance and complete their tasks, an office suite is a collection of bundled productivity software intended to be used by knowledge workers. The components are generally distributed together, have a consistent user interface and usually can interact with each other, the earliest office suite for personal computers was Starburst in the early 1980s, comprising the word processor WordStar, together with companion apps CalcStar and DataStar. Various other suites arose in the 1980s, and over the course of the 1990s Microsoft Office came to dominate the market, existing office suites contain wide range of various components
12.
Commodore 16
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The Commodore 16 is a home computer made by Commodore International with a 6502-compatible 7501 or 8501 CPU, released in 1984 and intended to be an entry-level computer to replace the VIC-20. A cost-reduced version, the Commodore 116, was only in Europe. The C16 and C116 belong to the family as the higher-end Plus/4 and are internally very similar to it. As a result, software is generally compatible among all three provided it can fit within the C16s smaller RAM and does not utilize the port on the Plus/4. While the C16 was a failure on the US market, it enjoyed some success in certain European countries, the C16 was intended to compete with other sub-$100 computers from Timex Corporation, Mattel, and Texas Instruments. The TI-99/4A was priced in-between Commodores VIC-20 and Commodore 64, and is somewhat between them in capability, but TI was lowering its prices, on paper, the C16 is a closer match for the TI-99/4A than the aging VIC-20. Commodore president Jack Tramiel feared that one or more Japanese companies would introduce a consumer-oriented computer, although the Japanese would soon dominate the U. S. video game console market, their feared dominance of the home computer field never materialized. Additionally, Timex, Mattel, and TI departed the computer market before the C16 was released, outwardly the C16 resembles the VIC-20 and the C64, but with a dark-gray case and light-gray keys. The keyboard layout differs slightly from the models, adding an escape key and four cursor keys replacing the shifted-key arrangement the C-64. The ROM resident BASIC3.5, however, is more powerful than the VIC-20s and C64s BASIC2.0, in that it has commands for sound and bitmapped graphics, as well as simple program tracing/debugging. From a practical point of view, three tangible features the C16 lacks are a modem port and VIC-20/C64-compatible Datasette and game ports. Commodore sold a C16-family-specific Datassette and joysticks, but third-party converters to allow the use of the abundant, the official reason for changing the joystick ports was to reduce RF interference. The C16s serial port was the same as that of the VIC-20 and Commodore 64, partially for cost reasons, the user port, designed for modems and other devices, was omitted from the C16. Despite costing less than the Plus/4, the C16s keyboard was higher quality, the Commodore 16 is one of three computers in its family. The even-less-successful Commodore 116 is functionally and technically similar but was shipped in a case with a rubber chiclet keyboard and was only available in Europe. The familys flagship, the Commodore Plus/4, was shipped in a case but has a 59-key full-travel keyboard,64 KB of RAM, a modem port. Although shipped with 16k from the factory, it was possible to modify the C16 for 64k, on power-up, the C16 defaults to the same color scheme as the VIC-20, with an aqua border, white background, and dark blue text unlike the Plus/4s purple/white/black colors. Hardware designer Bil Herd notes that the C116 is the member of this family of computers and is the original vision as imparted by Jack Tramiel to the engineering department
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.
Texas Instruments
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Texas Instruments Inc. is an American technology company that designs and manufactures semiconductors, which it sells to electronics designers and manufacturers globally. Headquartered in Dallas, Texas, United States, TI is one of the top ten semiconductor companies worldwide, Texas Instrumentss focus is on developing analog chips and embedded processors, which accounts for more than 85% of their revenue. TI also produces TI digital light processing technology and education technology products including calculators, microcontrollers, to date, TI has more than 43,000 patents worldwide. TI produced the worlds first commercial silicon transistor in 1950, Jack Kilby invented the integrated circuit in 1958 while working at TIs Central Research Labs. TI also invented the hand-held calculator in 1967, and introduced the first single-chip microcontroller in 1970, in 1987, TI invented the digital light processing device, which serves as the foundation for the companys award-winning DLP technology and DLP Cinema. In 1990, TI came out with the popular TI-81 calculator which made them a leader in the calculator industry. In 1997, its business was sold to Raytheon, which allowed TI to strengthen its focus on digital solutions. Texas Instruments was founded by Cecil H. Green, J. Erik Jonsson, Eugene McDermott, McDermott was one of the original founders of Geophysical Service Inc. in 1930. McDermott, Green, and Jonsson were GSI employees who purchased the company in 1941, in November,1945, Patrick Haggerty was hired as general manager of the Laboratory and Manufacturing division, which focused on electronic equipment. By 1951, the L&M division, with its contracts, was growing faster than GSIs Geophysical division. The company was reorganized and initially renamed General Instruments Inc, because there already existed a firm named General Instrument, the company was renamed Texas Instruments that same year. From 1956 to 1961, Fred Agnich of Dallas, later a Republican member of the Texas House of Representatives, was the Texas Instruments president, Geophysical Service, Inc. became a subsidiary of Texas Instruments. Early in 1988 most of GSI was sold to the Halliburton Company, in 1930, J. Clarence Karcher and Eugene McDermott founded Geophysical Service, an early provider of seismic exploration services to the petroleum industry. In 1939, the company reorganized as Coronado Corp. an oil company with Geophysical Service Inc, on December 6,1941, McDermott along with three other GSI employees, J. Erik Jonsson, Cecil H. Green, and H. B. During World War II, GSI expanded their services to include electronics for the U. S. Army, Signal Corps, in 1951, the company changed its name to Texas Instruments, GSI becoming a wholly owned subsidiary of the new company. Texas Instruments also continued to manufacture equipment for use in the seismic industry, after selling GSI, TI finally sold the company to Halliburton in 1988, at which point GSI ceased to exist as a separate entity. Texas Instruments entered the electronics market in 1942 with submarine detection equipment. During the early 1980s, Texas Instruments instituted a quality program which included Juran training, as well as promoting statistical process control, Taguchi methods and Design for Six Sigma
15.
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
16.
Commodore PET
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The Commodore PET is a line of home/personal computers produced starting in 1977 by Commodore International. The first model, which was named the PET2001, was the personal computer ever made available to retail consumers, after the Apple II. In the 1970s Commodore was one of many companies selling calculators designed around Dallas-based Texas Instruments chips. Commodore responded to this by searching for a set they could purchase outright. At Commodore, Peddle convinced Jack Tramiel that calculators were a dead-end, in September 1976 Peddle got a demonstration of Jobs and Wozniaks Apple II prototype, when Jobs was offering to sell it to Commodore, but Commodore considered Jobs offer too expensive. Tramiel demanded that Peddle, Bill Seiler, and John Feagans create a computer in time for the June 1977 Consumer Electronics Show, tramiels son, Leonard, helped design the PETSCII graphic characters and acted as quality control. The result was the first all-in-one home computer, the PET and its 6502 processor controlled the screen, keyboard, cassette tape recorders and any peripherals connected to one of the computers several expansion ports. The machine also included a built-in Datasette for data storage located on the front of the case, the data transfer rate to cassette tape was 1500 baud, but the data was recorded to tape twice for safety, giving an effective rate of 750 baud. The PET2001 was announced at the Winter CES in January 1977, however, the PET was back-ordered for months and to ease deliveries, early in 1978 Commodore decided to cancel the 4 kB version. However, this took six months to finally happen, during which time Microsoft lost money. At the end of the year, the company was saved by Apples decision to license Microsoft BASIC for the Apple II line. The key tops also tended to rub off easily, reliability was fairly poor, although that was not atypical of many early microcomputers. Because of the keyboard on the PET, external replacement ones quickly appeared. On the other hand, Commodore was a year behind Apple, in 1979, Commodore replaced the original PET2001 with an improved model known as the 2001-N. The new machine used a standard green-phosphor monitor in place of the blue in the original 2001. It now had a conventional, full-sized keyboard and no longer sported the built-in cassette recorder, the kernel ROM was upgraded to add support for Commodores newly introduced disk drive line. It was offered in 8kB, 16kB, or 32kB models as the 2001-N8, 2001-N16, the 2001-N switched to using conventional DRAM instead of the 6550 SRAM in the original model. PET 2001-8Ns had eight 2108 DRAMs and 2001-16Ns used sixteen 2108s, the PET4016 used eight 4116 chips
17.
MOS Technology VIC
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The VIC, specifically known as the MOS Technology 6560 /6561, is the integrated circuit chip responsible for generating video graphics and sound in the Commodore VIC-20 home computer. It was originally designed for such as low cost CRT terminals, biomedical monitors, control system displays. The chip was designed by Al Charpentier in 1977 but Commodore could not find a market for the chip, both of these chips failed due to memory timing constraints. Thus the VIC-20 employed the more expensive static RAM chips, but with the low RAM capacity of that machine, just 5 KB in the main box, memory expansions for the VIC-20 either used SRAM as well or implemented their own refresh circuit. The VIC was programmed by manipulating its 16 control registers, memory mapped to the range $9000–$900F in the VIC-20 address space, the on-chip A/D converters were used for dual paddle position readings by the VIC-20, which also used the VICs light pen facility. The VIC preceded the more advanced VIC-II, used by the VIC-20s successors. VIC-20s with expansion RAM have their memory at $1000 and when it is not present. User-defined character sets must be placed within the first 5k of system RAM, the default PETSCII character ROM is at $8000 and each character takes 8 bytes to store. Up to 128 characters may be used at any one time, while the PET had a backslash in its character set, this was replaced on the VIC-20 with a British pound sign. Programmable characters are the way of creating graphics and animation on the VIC as the chip does not have sprites or an all-points-addressable bitmap mode. Of the 16 colors in the palette, eight may be used for the foreground and border while the others are limited to the background, the MSB of the color RAM is a flag used to indicate if that character is multicolor or high resolution. Due to the extreme blockiness of the former, most VIC-20 games use hires characters, the VIC does not support scrolling or raster interrupts like on the VIC-II, but the scanline counters could be polled for a specific point on the screen to produce raster effects. This feature was used in games except for a few titles like iMagics Demon Attack. Sound programming on the VIC is done by placing a frequency value in one of the four registers at $900A-$900D, the first three are square wave generators pitched half an octave from each other and the fourth is for white noise. The VIC has 16 read/write registers listed below, MOS Technology 6560 NTSC MOS Technology 6561E PAL Ceramic version, used in early VIC-20s MOS Technology 6561-101 PAL Bagnall, on The Edge, The Spectacular Rise and Fall of Commodore
18.
Commodore VIC-20
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The VIC-20 is an 8-bit home computer that was sold by Commodore Business Machines. The VIC-20 was announced in 1980, roughly three years after Commodores first personal computer, the PET, the VIC-20 was the first computer of any description to sell one million units. The VIC-20 was intended to be more economical than the PET computer and it was equipped with 5 KB of static RAM and used the same MOS6502 CPU as the PET. As the Apple II gained momentum with the advent of VisiCalc in 1979, Jack Tramiel wanted a product that would compete in the same segment, for this reason Chuck Peddle and Bill Seiler started to design a computer named TOI. The TOI computer failed to materialize, mostly because it required an 80-column character display which in turn required the MOS Technology 6564 chip, however, the chip could not be used in the TOI since it required very expensive static RAM to operate fast enough. The serial IEEE 488-derivative CBM-488 interface was designed by Glen Stark, some features, like the memory add-in board, were designed by Bill Seiler. Altogether, the VIC20 development team consisted of five people, wed swipe whatever equipment we needed to get our jobs done. There was no way to get the work done. Theyd discover it was missing and they would just order more stuff from the warehouse, at the time, Commodore had an oversupply of 1 kbit×4 SRAM chips, so Tramiel decided that these should be used in the new computer. The end result was closer to the PET or TOI computers than to Yannes prototype. The original Revision A system board found in all silver-label VIC-20s used 2114 SRAMs and due to their tiny size, ten of them were required to reach 5k of system RAM. The Revision B system board, found in rainbow logo VIC-20s switched to larger 2048 byte SRAMs which reduced the count to five chips,2 x 2048 bytes chips +3 x 2114 chips. VIC-20s went through several variations in their 3-1/2 years of production, first-year models had a PET-style keyboard with a blocky font while most VIC-20s made during 1982 had a slightly different keyboard also shared with early C64s. The rainbow logo VIC-20 was introduced in early 1983 and has the newer C64 keyboard with gray function keys and it has a similar power supply to the C64 PSU, although the amperage is slightly lower. Older Revision A VIC-20s cannot use a C64 PSU or vice versa as their power requirement is too high, in April 1980, at a meeting of general managers outside London, Jack Tramiel declared that he wanted a low-cost color computer. When most of the GMs argued against it, he said, The Japanese are coming and this was in keeping with Tramiels philosophy which was to make computers for the masses, not the classes. Then, the project was given to Commodore Japan, a team led by Yash Terakura created the VIC-1001 for the Japanese market. The VIC-20 was marketed in Japan as VIC-1001 before VIC-20 was introduced to the US, when they returned to California from that meeting, Tomczyk wrote a 30-page memo detailing recommendations for the new computer, and presented it to Tramiel
19.
Jack Tramiel
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Jack Tramiel was a Polish American businessman, best known for founding Commodore International. The Commodore PET, Commodore VIC-20 and Commodore 64 are some home computers produced while he was running the company, Tramiel later formed Atari Corporation after he purchased the remnants of the original Atari, Inc. from its parent company. Tramiel was born as Idek Trzmiel into a Jewish family, the son of Abram Josef Trzmiel, after the German invasion of Poland in 1939 his family was transported by German occupiers to the Jewish ghetto in Łódź, where he worked in a garment factory. When the ghettos were liquidated his family was sent to the Auschwitz concentration camp and he was examined by Josef Mengele and selected for a work party, after which he and his father were sent to the labor camp Ahlem near Hanover, while his mother remained at Auschwitz. Like many other inmates, his father was reported to have died of typhus in the camp, however. Tramiel was rescued from the camp in April 1945 by the 84th Infantry Division of the US army. On 10 November 1947, Tramiel immigrated to the United States and he soon joined the U. S. Army, where he learned how to repair office equipment, including typewriters. In 1953, while working as a driver, Tramiel bought a shop in the Bronx to repair office machinery. He named it Commodore Portable Typewriter, Tramiel wanted a military-style name for his company, but names such as Admiral and General were already taken, so he settled on the Commodore name. In 1955, Tramiel signed a deal with a Czechoslovak typewriter manufacturer Zbrojovka Brno NP to assemble, in 1962, Commodore went public, but the arrival of Japanese typewriters in the U. S. market made the selling of Czechoslovakian typewriters unprofitable. Stung twice by the source, Gould suggested that Tramiel travel to Japan to learn why they were able to outcompete North Americans in their own local markets. It was during this trip that Tramiel saw the first digital calculators, when Commodore released its first calculators, combining an LED display from Bowmar and an integrated circuit from Texas Instruments, it found a ready market. However, after realizing the size of the market, TI decided to cut Commodore out of the middle. When their lead designer, Chuck Peddle, told Tramiel that calculators were an end and computers were the future. Peddle responded with the Commodore PET, based on his companys MOS Technology 6502 processor and it was first shown, privately, at the Chicago Consumer Electronics Show in 1977, and soon the company was receiving 50 calls a day from dealers wanting to sell the computer. The PET became a success—especially in the field, where its all-in-one design was a major advantage. Much of their success with the PET came from the decision to sell directly to large customers. The first PET computers were sold primarily in Europe, where Commodore had also introduced the first wave of digital handheld calculators, Commodore responded with the VIC-20, and then the Commodore 64, which became the best-selling home computer of all time
20.
MOS Technology 6502
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The MOS Technology 6502 is an 8-bit microprocessor that was designed by a small team led by Chuck Peddle for MOS Technology. When it was introduced in 1975, the 6502 was, by a considerable margin and it initially sold for less than one-sixth the cost of competing designs from larger companies, such as Motorola and Intel, and caused rapid decreases in pricing across the entire processor market. Along with the Zilog Z80, it sparked a series of projects that resulted in the computer revolution of the early 1980s. Popular home video consoles and computers, such as Atari, Apple II, Nintendo Entertainment System, Commodore PET and others. Soon after the 6502s introduction, MOS Technology was purchased outright by Commodore International, in the early days of the 6502, it was second-sourced by Rockwell and Synertek, and later licensed to other companies. The 6502 was designed by many of the engineers that had designed the Motorola 6800 microprocessor family. Motorola started the 6800 microprocessor project in 1971 with Tom Bennett as the main architect, the chip layout began in late 1972, the first 6800 chips were fabricated in February 1974 and the full family was officially released in November 1974. John Buchanan was the designer of the 6800 chip and Rod Orgill, Bill Mensch joined Motorola in June 1971 after graduating from the University of Arizona. His first assignment was helping define the peripheral ICs for the 6800 family, Motorolas engineers could run analog and digital simulations on an IBM 370-165 mainframe computer. Bennett hired Chuck Peddle in 1973 to do architectural work on the 6800 family products already in progress. He contributed in areas, including the design of the 6850 ACIA. Motorolas target customers were established electronics companies such as Hewlett-Packard, Tektronix, TRW, in May 1972, Motorolas engineers began visiting select customers and sharing the details of their proposed 8-bit microprocessor system with ROM, RAM, parallel and serial interfaces. In early 1974, they provided engineering samples of the chips so that customers could prototype their designs, Motorolas total product family strategy did not focus on the price of the microprocessor, but on reducing the customers total design cost. They offered development software on a computer, the EXORciser system debugging system, onsite training. Both Intel and Motorola had initially announced a price for a single microprocessor. The actual price for production quantities was much less, Motorola offered a design kit containing the 6800 with six support chips for $300. Peddle, who would accompany the people on customer visits. To lower the price, the IC chip size would have to shrink so that more chips could be produced on each silicon wafer and this could be done by removing inessential features in the 6800 and using a newer fabrication technology, depletion-mode MOS transistors
21.
IBM PC compatible
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IBM PC compatible computers are those similar to the original IBM PC, XT, and AT, able to run the same software and support the same expansion cards as those. Such computers used to be referred to as PC clones, or IBM clones, Columbia Data Products built the first clone of the IBM personal computer by a clean room implementation of its BIOS. Early IBM PC compatibles used the computer bus as the original PC. The IBM AT compatible bus was named the Industry Standard Architecture bus by manufacturers of compatible computers. The term IBM PC compatible is now a historical description only, only the Apple Macintosh classic Mac OS and macOS kept significant market share without compatibility with the IBM personal computer, so consumers are typically identified as being a PC or Mac user. IBM decided in 1980 to market a low-cost single-user computer as quickly as possible in response to Apple Computers success in the microcomputer market. On 12 August 1981, the first IBM PC went on sale, there were three operating systems available for it. The least expensive and most popular was PC DOS made by Microsoft, in a crucial concession, IBMs agreement allowed Microsoft to sell its own version, MS-DOS, for non-IBM computers. The only component of the original PC architecture exclusive to IBM was the BIOS and this software would run on any machine using MS-DOS or PC-DOS. Software that directly addressed the hardware instead of making standard calls was faster, however, software addressing IBM PC hardware in this way would not run on MS-DOS machines with different hardware. The 808x computer marketplace rapidly excluded all machines which were not hardware-, the 640 KB barrier on conventional system memory available to MS-DOS is a legacy of that period, other non-clone machines, while subject to a limit, could exceed 640 kB. Rumors of lookalike, compatible computers, created without IBMs approval, by June 1983 PC Magazine defined PC clone as a computer accommodate the user who takes a disk home from an IBM PC, walks across the room, and plugs it into the foreign machine. Because of a shortage of IBM PCs that year, many customers purchased clones instead, Columbia Data Products produced the first computer more or less compatible to the IBM PC standard during June 1982, soon followed by Eagle Computer. Compaq announced its first IBM PC compatible in November 1982, the Compaq Portable, the Compaq was the first sewing machine-sized portable computer that was essentially 100% PC-compatible. The company could not copy the BIOS directly as a result of the decision in Apple v. Franklin. Each computer would have its own Original Equipment Manufacturer version of MS-DOS, any software written for MS-DOS would operate on any MS-DOS computer, despite variations in hardware design. This expectation seemed reasonable in the marketplace of the time. Until then Microsoft was based primarily on computer languages such as BASIC, the established small system operating software was CP/M from Digital Research which was in use both at the hobbyist level and by the more professional of those using microcomputers
22.
Leading Edge Model D
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The Leading Edge Model D was an IBM clone computer first released by Leading Edge Hardware in July 1985. It was initially priced at $1,495 configured with dual 5.25 floppy drives,256 KB of RAM, and it was manufactured by South Korean conglomerate Daewoo and distributed by Canton, Massachusetts-based Leading Edge. Engineer Stephen Kahng spent about four months designing the Model D at a cost of $200,000, Kahng later became CEO of Macintosh clone maker Power Computing. In August 1986, Leading Edge cut the price of the model by $200, to $1,295. The Model D was an success, selling 100,000 units in its first year of production. It continued to sell well for years, until a dispute with its dealers forced Leading Edge into bankruptcy in 1989. The Model D initially featured an Intel 8088 microprocessor at 4.77 MHz, earlier models had no turbo switch and ran only at 4.77 MHz, while a few of the later ones were 7.16 MHz only. Three models are known, DC-2011, DC-2010E, and DC-2011E, the E seems to correlate with the capability of running at 7.16 MHz. This allowed the Model D to be half the size of IBMs models, there were four full-length ISA expansion slots available. The motherboard came in eight different revisions, Revision 1,5,7,8, CC1, CC2, WC1, a list of motherboard part numbers and revision numbers can be found here. Revisions 1 through 7 were usually found in model DC-2011, with revisions 8 through WC2 being either in 2010E or 2011E, due to its tight integration, the Model D motherboard was a nonstandard form factor, so replacing the motherboard with an off-the-shelf upgrade was not possible. They came preinstalled with 256,512, or 640 KB of RAM, lower-capacity machines were user upgradeable to 640 KB. Motherboard revisions 7,8, WC1 and WC2 came with 768 KB of RAM installed, some models featured a monochrome/CGA selection switch, with a single port used for both modes. Some models had both a Monochrome and a CGA port, also with a switch to change modes, the Model D computers supported a special extended graphics mode, 640x200. The buyer had the choice between a floppy disk model and a fixed disk model, the floppy disk model had one or two 360 KB drives, so that the user could run MS-DOS programs on the primary drive and work with files on the secondary drive, if equipped. The fixed disk model had one 360 KiB floppy drive and either a 10 MB,20 MB, the model with the 20 MB fixed disk was initially released in February 1986 at a cost of $1,895. Leading Edge dealers had difficulty keeping the 20MB model in stock, at the time, a Tandy 1200 equipped with a 10MB drive sold for $1999. The buyer also had a choice between an amber or a green monochrome CRT monitor, the unit came with MS-DOS2.11 or later, and a special edition of GW-BASIC to support the extended graphics mode
23.
Tandy 1000
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The Tandy 1000 was the first in a line of more-or-less IBM PC compatible home computer systems produced by the Tandy Corporation for sale in its RadioShack chain of stores. In December 1983 an executive with Tandy Corporation, maker of TRS-80 computers, said about the new IBM PCjr home computer, Im sure a lot of people will be coming out with PCjr look-alikes. Released in November 1984, the $1,200 Tandy 1000 was designed as an inexpensive PC clone with enhancements compatible with the PCjr, but with a better keyboard. How could IBM have made that mistake with the PCjr. an amazed Tandy executive said regarding its chiclet keyboard, the 1000 included joystick ports like the PCjr, and copied its 16-color graphics and 3-voice sound, but not the PCjr ROM cartridge ports. Since IBM discontinued the PCjr soon after the release of the 1000, although Tandy initially marketed the 1000 as a business computer like the IBM PC, InfoWorld stated in 1985 that the unwritten potential for the machine is in the elusive home computer market. Tandy produced a home computer. The company claimed that the 1000 was the first fully IBM PC-compatible computer available for less than $1000. It helped the company obtain a 9. 5% share of the US home-computer market in 1986, in 1988 CEO John Roach disagreed with Apple counterpart John Sculleys rejection of the home market, Let him deny it. Hes the only person thats well-represented in the home market. Tandy also gained a significant share of the market, which Apple historically had dominated. The PCjrs enhanced graphics and sound standards became known as Tandy-compatible, with its graphics, sound, and built-in joystick ports, the 1000 was the best computer for PC games until VGA graphics became popular in the 1990s. Software companies of the era advertised their support for the Tandy platform,28 of 66 games that Computer Gaming World tested in 1989 supported Tandy graphics, successors to the 1000 appended two or three letters to the name, after a space. In a few instances, after these letters a slash was appended, followed by either a number or additional letters, although the original 1000 came in an IBM PC-like desktop case, some others used home-computer-style cases with the keyboard, motherboard and disk drives in one enclosure. Tandy 1000 computers were some of the first IBM PC clones to incorporate a set of basic peripherals on the motherboard using proprietary ASICs. This is in addition to the standard on the IBM PC, PC/XT, and PC/AT motherboards, keyboard interface, expansion slots, memory subsystem, interrupt controller. Like the PCjr, the 1000 uses up to 32K of system RAM for display memory, the earlier models of the Tandy 1000 had a composite video output, and could be used with a color or monochrome composite monitor, or a TV with an RF modulator. The original 1000 and SX had a light-pen port, unlike most PC clones, several Tandy 1000 computers had MS-DOS built into ROM and could boot in a few seconds. Tandy bundled DeskMate, a suite of consumer-oriented applications, with various Tandy 1000 models
24.
Commodore CBM-II
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The Commodore CBM-II series is a short-lived range of 8-bit personal computers from Commodore Business Machines, released in 1982 and intended as a follow-on to the Commodore PET series. The CBM-II has two incarnations, the P series and the B series, the B series was available with a built-in monochrome monitor with detached keyboard, and also as a single unit with built-in keyboard but no monitor. These machines are known as the Porsche PETs for their unique styling, the P-series uses the VIC-II 40-column color video chip like the C64. It also includes two standard Atari-style joystick ports, the 6509 CPU runs at 1 MHz in the P-series due to the use of the VIC-II chip. Both B and P-series machines have a SID chip, although the B-series 2Mhz clock speed makes it impossible to read any of the SIDs registers. The B-series uses a 6545 CRTC video chip to give an 80-column green screen monochrome output more suitable for word processing, most models have the Motorola 68B45 installed which is a pin-compatible variant rather than the MOS 6545A12 MHz part. On the B-series the 6509 CPU runs at 2 MHz, the joystick ports are not present on the B-series, but the connector is still on the motherboard. CBM-IIs are the only Commodore 8-bit machines with an RS-232 port instead of the user port. The I/O registers for the port are still present but there is no connector for it on the motherboard. A cartridge slot is included on the machines, however no known cartridge software was developed. The B-series retained the IEEE-488 interface from the PET instead of the IEC serial interface on the VIC-20, IEC drives will require an adapter as well as a modified kernal ROM. The small amount of software Commodore developed for the B-series was distributed on 500k 8050 format disks rather than the 170k 4040/1541 format. Features common to both the P and B-series included an MOS Technology 6509 CPU, a version of the venerable 6502. The sound chip is the 6581 SID, the one that was used in the popular Commodore 64. Additionally, the CBM-II has an industry-standard RS-232 serial interface and an IEEE-488 parallel bus just like the PET/CBM series, the CBM-IIs built-in operating system uses an enhanced version of CBM BASIC version 4.0. The coprocessor board only runs on high-profile machines due to power supply, a Z80 card was also announced if the user wished to run CP/M-80, as well as a Z8001 board, but none are known to exist. The 8088 board never reached production apparently because of getting it to work with the system. The CBM-II line uses a complicated RAM banking scheme, Bank 0 contains the video RAM on P-series machines and is empty on B-series machines
25.
Denmark
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The term Danish Realm refers to the relationship between Denmark proper, the Faroe Islands and Greenland—three countries constituting the Kingdom of Denmark. The legal nature of the Kingdom of Denmark is fundamentally one of a sovereign state. The Faroe Islands and Greenland have been part of the Crown of Denmark since 1397 when the Kalmar Union was ratified, legal matters in The Danish Realm are subject to the Danish Constitution. Beginning in 1953, state law issues within The Danish Realm has been governed by The Unity of the Realm, a less formal name for The Unity of the Realm is the Commonwealth of the Realm. In 1978, The Unity of The Realm was for the first time referred to as rigsfællesskabet. The name caught on and since the 1990s, both The Unity of The Realm and The Danish Realm itself has increasingly been referred to as simply rigsfællesskabet in daily parlance. The Danish Constitution stipulates that the foreign and security interests for all parts of the Danish Realm are the responsibility of the Danish government, the Faroes received home rule in 1948 and Greenland did so in 1979. In 2005, the Faroes received a self-government arrangement, and in 2009 Greenland received self rule, the Danish Realms unique state of internal affairs is acted out in the principle of The Unity of the Realm. This principle is derived from Article 1 of the Danish Constitution which specifies that constitutional law applies equally to all areas of the Danish Realm, the Constitutional Act specifies that sovereignty is to continue to be exclusively with the authorities of the Realm. The language of Denmark is Danish, and the Danish state authorities are based in Denmark, the Kingdom of Denmarks parliament, with its 179 members, is located in the capital, Copenhagen. Two of the members are elected in each of Greenland and the Faroe Islands. The Government ministries are located in Copenhagen, as is the highest court, in principle, the Danish Realm constitutes a unified sovereign state, with equal status between its constituent parts. Devolution differs from federalism in that the powers of the subnational authority ultimately reside in central government. The Self-Government Arrangements devolves political competence and responsibility from the Danish political authorities to the Faroese, the Faroese and Greenlandic authorities administer the tasks taken over from the state, enact legislation in these specific fields and have the economic responsibility for solving these tasks. The Danish government provides a grant to the Faroese and the Greenlandic authorities to cover the costs of these devolved areas. The 1948 Home Rule Act of the Faroe Islands sets out the terms of Faroese home rule, the Act states. the Faroe Islands shall constitute a self-governing community within the State of Denmark. It establishes the government of the Faroe Islands and the Faroese parliament. The Faroe Islands were previously administered as a Danish county, the Home Rule Act abolished the post of Amtmand and these powers were expanded in a 2005 Act, which named the Faroese home government as an equal partner with the Danish government
26.
TDC A/S
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TDC A/S is a Danish telecommunications company dating back to 1879. TDC is the largest telephone company in Denmark with 8.5 million customer relations within telephony, broadband, the companys headquarters are located in Copenhagen. Even though the Danish home market is the focus of business, TDC is also represented as a market challenger in Norway, Sweden. Beside the parent company, the TDC-group consists of a number of subsidiaries and brands, Companymobile, Dansk Kabel TV, Fullrate, Get AS, Cirque A/S, NetDesign, Telmore, Unotel,21 August 1882 is therefore considered TDC’s foundation date. In 1990 KTAS was renamed to Tele Danmark, Tele Danmark was created as a new umbrella parent company for the existing regional telecos. In 1995 this co-operation was taken one step further when the four companies were formally merged into Tele Danmark. In January 2000 TDC got a new logo with five ovals in red, yellow, green, turquoise, in December 2000 Tele Danmark changed its name to TDC. Over the past decade, TDC developed from a traditional and mainly Danish provider of landline, deregulation of the Danish telecommunications market in 1996 created a highly competitive market. In 2004, the Danish telecommunications market was fully liberalized, in 2006 TDC adopted a new logo which consists of a cursive rounded-rectangle in blue colour. The text TDC appears in the rectangle and remind that the letter D is cut a little bit, a group of private equity firms under the banner Nordic Telephone Company offered to buy TDC for a price of about 9.1 billion Euro. Among the group were such as Blackstone, Permira, Apax Partners. The company bought 88% of the shares, but failed to buy more than 90% of the shares and was unable to remove the company completely from the Copenhagen Stock Exchange. Also in 2006, TDC pulled out of the UK mobile telephone market, with the closure of their joint venture with EasyGroup, to emphasise a separate identity for its cable television operations TDC Kabel TV changed its legal name to YouSee A/S on 1 October 2007. In 2010 Nordic Telephone Company began the process of selling its shares in TDC on the Copenhagen Stock Exchange, in 2012 TDC had a total revenue of 26 billion DKK, and employed around 9,000 people in Denmark. In 2014 TDC purchased the Norwegian telecommunications firm Get AS for 12.5 billion Danish crowns, in 2016 TDC purchased Danish IT- and telecom provider Cirque A/S for an unspecified amount. 1990-1999 Tele Danmark introduced its first logo in 1990 and it is a cursive square in blue colour which carries the text TELE. The text DANMARK is next to the blue square, 2000-2005 Tele Danmark adopted its new logo in January 2000. The new logo has five ovals in red, yellow, green, turquoise, by December 2000, Tele Danmark was renamed to TDC and redesigned its 2000 logo as the text Tele Danmark gets removed from the logo
27.
Hungary
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Hungary is a unitary parliamentary republic in Central Europe. With about 10 million inhabitants, Hungary is a member state of the European Union. The official language is Hungarian, which is the most widely spoken language in Europe. Hungarys capital and largest metropolis is Budapest, a significant economic hub, major urban areas include Debrecen, Szeged, Miskolc, Pécs and Győr. His great-grandson Stephen I ascended to the throne in 1000, converting the country to a Christian kingdom, by the 12th century, Hungary became a middle power within the Western world, reaching a golden age by the 15th century. Hungarys current borders were established in 1920 by the Treaty of Trianon after World War I, when the country lost 71% of its territory, 58% of its population, following the interwar period, Hungary joined the Axis Powers in World War II, suffering significant damage and casualties. Hungary became a state of the Soviet Union, which contributed to the establishment of a four-decade-long communist dictatorship. On 23 October 1989, Hungary became again a democratic parliamentary republic, in the 21st century, Hungary is a middle power and has the worlds 57th largest economy by nominal GDP, as well as the 58th largest by PPP, out of 188 countries measured by the IMF. As a substantial actor in several industrial and technological sectors, it is both the worlds 36th largest exporter and importer of goods, Hungary is a high-income economy with a very high standard of living. It keeps up a security and universal health care system. Hungary joined the European Union in 2004 and part of the Schengen Area since 2007, Hungary is a member of the United Nations, NATO, WTO, World Bank, the AIIB, the Council of Europe and Visegrád Group. Well known for its cultural history, Hungary has been contributed significantly to arts, music, literature, sports and science. Hungary is the 11th most popular country as a tourist destination in Europe and it is home to the largest thermal water cave system, the second largest thermal lake in the world, the largest lake in Central Europe, and the largest natural grasslands in Europe. The H in the name of Hungary is most likely due to historical associations with the Huns. The rest of the word comes from the Latinized form of Medieval Greek Oungroi, according to an explanation the Greek name was borrowed from Proto-Slavic Ǫgǔri, in turn borrowed from Oghur-Turkic Onogur. Onogur was the name for the tribes who later joined the Bulgar tribal confederacy that ruled the eastern parts of Hungary after the Avars. The Hungarians likely belonged to the Onogur tribal alliance and it is possible they became its ethnic majority. The Hungarian endonym is Magyarország, composed of magyar and ország, the word magyar is taken from the name of one of the seven major semi-nomadic Hungarian tribes, magyeri
28.
Commodore Datasette
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The Commodore 1530 Datasette was Commodores dedicated magnetic tape data storage device. Using compact cassettes as the medium, it provided inexpensive storage to Commodores 8-bit home/personal computers, notably the PET, VIC-20. A physically similar model, Commodore 1531, was made for the Commodore 16, unlike most microcomputer storage methods using compact cassettes, the Datasette uses a digital format. Instead of writing two tones to tape to indicate bits, patterns of waves are used including a parity bit. Programs are written twice to tape for error correction, if an error is detected when reading the first recording, the Datasette has built-in analog to digital converters and audio filters to convert the computers digital data into analog sound and vice versa. Connection to the computer is done via an edge connector or mini-DIN connector. The Datasette was more popular outside than inside the United States, in the United States disk drives quickly became standard, despite the Commodore 1541 floppy drive costing roughly five times as much as a Datasette. In most parts of Europe, the Datasette was the medium of choice for years after its launch. The inexpensive and widely available audio cassettes made the Datasette a good choice for the home computer mass market. The Datasette is slow—but because of its digital format extremely reliable—transferring data at around 50 bytes per second, after the Datasettes launch, however, special turbo tape software appeared, providing much faster tape operation. Such software was integrated into most commercial prerecorded applications, as well as being available separately for loading and saving the users homemade programs and these programs were only widely used in Europe, as the US market had long since moved onto disks. Datasettes can typically store about 100 kByte per 30 minute side, the use of turbo tape and other fast loaders increased this number to roughly 1000 kByte. The Datasette has only one cable with a PCB edge connector at the computer end. All input/output signals to the datasette are all digital and so all digital to analog, power is also included in this cable. The pinout is ground, +5 V DC, motor, read, write, the sense signal monitors the play, rewind, and fast-forward buttons, but cannot differentiate between them. A mechanical interlock prevented any two of them being pressed at the same time, unregulated 6.36 V DC is used to power the cassette motor. To record physical data, the zero-crossing from positive to negative voltage of the signal is measured. The resulting time between these positive to negative crossings is then compared to a threshold to determine whether the time since the last crossing is short or long, note the lower amplitude for the shorter periods
29.
Atari 8-bit family
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The Atari 8-bit family is a series of 8-bit home computers introduced by Atari, Inc. in 1979 and manufactured until 1992. All of the machines in the family are similar and differ primarily in packaging. They are based on the MOS Technology 6502 CPU running at 1.79 MHz, star Raiders is widely considered the platforms killer app. The original Atari 400 and 800 models were released with a series of plug-n-play peripherals that used Ataris SIO serial bus system, to meet stringent FCC requirements, the early machines were completely enclosed in a solid cast aluminum block, which made them physically robust but expensive to produce. Over the following decade, the models were replaced by the XL and XE series which had the same basic logical design. The Atari 8-bit computer line sold two million units during its production run between late 1979 and mid-1985. They were not only sold through dedicated computer retailers, but department stores such as Sears, the primary competition in the worldwide market was, starting in 1982, the Commodore 64. This was the first computer to offer similar performance. Atari also found a market in Eastern Europe and had something of a renaissance in the early 1990s as these countries joined a uniting Europe. On January 1,1992, Atari corp, officially dropped all remaining support of the 8-bit line. Design of the 8-bit series of machines started at Atari as soon as the Atari 2600 games console was released in late 1977. While designing the 2600 in 1976, the team from Atari Grass Valley Research Center felt that the 2600 would have about a three-year lifespan before becoming obsolete. They started blue sky designs for a new console that would be ready to replace it around 1979, what they ended up with was essentially a greatly updated version of the 2600, fixing its more obvious limitations but sharing a similar overall design philosophy. The newer design would be faster than the 2600, have better graphics, work on the chips for the new system continued throughout 1978 and focused on much-improved video hardware known as the Color Television Interface Adaptor, or CTIA. During this gestation the home computer era began in earnest in the form of the TRS-80, Commodore PET, Warner Communications had purchased Atari from Nolan Bushnell for $28 million in 1976 in order to fund the launch of the 2600. Atari had recently sent Ray Kassar to act as the CEO of the company, Kassar felt the chipset should be used in a home computer to challenge Apple. In order to adapt the machine to this role, it would need to support character graphics, include some form of expansion for peripherals, and run the then-universal BASIC programming language. The CTIA, like the 2600s TIA, was designed to produce Player-Missile graphics, instead of expanding the CTIA to handle these tasks, the designers instead introduced an entirely new chip for this purpose, the Alphanumeric Television Interface Controller, or ANTIC
30.
Memory map
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In computer science, a memory map is a structure of data that indicates how memory is laid out. Memory maps can have a different meaning in different parts of the operating system and it is the fastest and most flexible cache organization which uses an associative memory. The associative memory stores both the address and content of the memory word, in the boot process, a memory map is passed on from the firmware in order to instruct an operating system kernel about memory layout. It contains the information regarding the size of memory, any reserved regions. In native debugger programs, a memory map refers to the mapping between loaded executable/library files and memory regions and these memory maps are used to resolve memory addresses to actual symbols. The PC BIOS provides a set of routines that can be used by operating system to get memory layout. Some of the routines are, BIOS Function, INT 0x15, AX=0xE801. It is supported by AMI BIOSses dated 8/23/94 or later, the operating system just sets AX to 0xE801 then calls int 0x15. If some error has happened, the routine returns with CF set to 1, then set registers as specified in Input table. On first call, EBX should be set to 0, next step is to call INT 0x15. If no error, the interrupt call returns with CF clear, EBX is updated by BIOS so that when the OS calls the routine again, The next region is returned in the buffer. BIOS sets EBX to zero if all done
31.
Bank switching
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Bank switching is a technique used in computer design to increase the amount of usable memory beyond the amount directly addressable by the processor. It can be used to configure a system differently at different times, for example, in video game systems, bank switching allowed larger games to be developed for play on existing consoles. Bank switching originated in minicomputer systems, the technique was common in 8-bit microcomputer systems. Bank-switching may also be used to work around limitations in address bus width, unlike memory management by paging, data is not exchanged with a mass storage device like disk storage. Data remains in quiescent storage in a area that is not currently accessible to the processor. Bank switching can be considered as a way of extending the address bus of a processor with some external register, for example, a processor with a 16-bit external address bus can only address 216 =65536 memory locations. If an external latch was added to the system, it could be used to control which of two sets of memory devices, each with 65536 addresses, could be accessed, the processor could change which set is in current use by setting or clearing the latch bit. Several bank-switching control bits could be gathered into a register, approximately doubling the available memory spaces with each bit in the register. The extra memory is not seamlessly available to programs, internal registers of the processor remain at their original length, so the processor cannot directly span all of bank-switched memory by, for example, incrementing an internal register. Instead the processor must explicitly do an operation to access large memory objects. This area would be used to code that manages the transitions between banks, and also to process interrupts. The application program must keep track of which memory bank holds a piece of data. However, bank-switching can access data much faster than, for example, processors with 16-bit addressing commonly used in early video game consoles and home computers can directly address only 64 KB. Systems with more memory had to divide the space into a number of blocks that could be dynamically mapped into parts of a larger address space. Bank switching was used to achieve this larger space by organizing memory into separate banks of up to 64KB each. Blocks of various sizes were switched in and out via bank select registers or similar mechanisms, cromemco was the first microcomputer manufacturer to use bank switching, supporting 8 banks of 64KB in its systems. When using bank switching some caution was required in order not to corrupt the handling of calls, interrupts, the machine stack. While the contents of memory temporarily switched out from the CPU was inaccessible to the processor, it could be used by hardware, such as video display, DMA, I/O devices
32.
Structured programming
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It emerged in the late 1950s with the appearance of the ALGOL58 and ALGOL60 programming languages, with the latter including support for block structures. Dijkstra, who coined the term structured programming, Structured programming is most frequently used with deviations that allow for clearer programs in some particular cases, such as when exception handling has to be performed. Following the structured program theorem, all programs are seen as composed of control structures, Sequence, selection, one or a number of statements is executed depending on the state of the program. This is usually expressed with such as if. then. else. endif. Iteration, a statement or block is executed until the program reaches a certain state and this is usually expressed with keywords such as while, repeat, for or do. until. Often it is recommended that each loop should only have one entry point, recursion, a statement is executed by repeatedly calling itself until termination conditions are met. While similar in practice to iterative loops, recursive loops may be computationally efficient. Subroutines, callable units such as procedures, functions, methods, blocks are used to enable groups of statements to be treated as if they were one statement. It is possible to do structured programming in any programming language, Structured programming enforces a logical structure on the program being written to make it more efficient and easier to understand and modify. The structured program theorem provides the basis of structured programming. It states that three ways of combining programs—sequencing, selection, and iteration—are sufficient to express any computable function, therefore, a processor is always executing a structured program in this sense, even if the instructions it reads from memory are not part of a structured program. However, authors usually credit the result to a 1966 paper by Böhm and Jacopini, the structured program theorem does not address how to write and analyze a usefully structured program. These issues were addressed during the late 1960s and early 1970s, with contributions by Dijkstra, Robert W. Floyd, Tony Hoare, Ole-Johan Dahl. Neither the proof by Böhm and Jacopini nor our repeated successes at writing structured code brought them one day sooner than they were ready to convince themselves. Donald Knuth accepted the principle that programs must be written with provability in mind, in his 1974 paper, Structured Programming with Goto Statements, he gave examples where he believed that a direct jump leads to clearer and more efficient code without sacrificing provability. Many of those knowledgeable in compilers and graph theory have advocated allowing only reducible flow graphs, as late as 1987 it was still possible to raise the question of structured programming in a computer science journal. Frank Rubin did so in that year with a letter titled GOTO considered harmful considered harmful. Numerous objections followed, including a response from Dijkstra that sharply criticized both Rubin and the other writers made when responding to him
33.
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
34.
Commodore 1551
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The Commodore 1551 is a floppy disk drive for the Commodore Plus/4 home computer. It resembles a charcoal-colored Commodore 1541 and plugs into the cartridge port, Commodore reportedly planned an interface to allow use of the 1551 with the C64, but it was never released. Aside from faster access, the drive is very similar to the 1541 and this became common practice, even more so since single-sided media became rarely available with prices matching those of double-sided disks. The disk drive uses group coded recording and contains an MOS Technology 6510T processor as a disk controller, the 6510T is a specialized version of the 6510 processor used in the C64, and it is only used in the 1551. The DOS limits the number of files per disk to 144 regardless of the number of blocks on the disk because the directory is of a fixed size. Its DOS is compatible with the 1541, so disks written by one drive can be utilized in the other, the 1551 is less common than other Commodore disk drives. The 1541 was more available as it is compatible with the popular C64 and VIC-20. Since the 1551 is compatible only with the Plus/4, which was a seller in the United States. In Europe, the Plus/4 was much more successful, but because tape drives were the most popular storage device in Europe in the 1980s, the 1551 has no dip switches to change the drives device number. It is possible to connect a maximum of two 1551s to one computer, the 1551s data transfer speed is about 1 kB per second. It is about 3 times as fast as the 1541
35.
Commodore 1541
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The Commodore 1541 is a floppy disk drive which was made by Commodore International for the Commodore 64, Commodores most popular home computer. The best-known floppy disk drive for the C64, the 1541 is a single-sided 170-kilobyte drive for 5¼ disks, the 1541 directly followed the Commodore 1540. The disk drive uses group coded recording and contains a MOS Technology 6502 microprocessor, doubling as a disk controller, the number of sectors per track varies from 17 to 21. The drives built-in disk operating system is CBM DOS2.6, the 1541 was priced at under US$400 at its introduction. A C64 plus a 1541 cost about $900, while an Apple II with no disk drive cost $1295, the first 1541 drives produced in 1982 have a label on the front reading VIC-1541 and have an off-white case to match the VIC-20. In 1983, the 1541 was switched to having the familiar beige case, by 1983 a 1541 sold for $300 or less, much less than the price of other computers disk drives. After a brutal home-computer price war that Commodore began, the C64 and 1541 together cost under $500, the drive became very popular, and became difficult to find. The magazine reported in March 1984 that it received three defective drives in two weeks, and Compute. s Gazette reported in December 1983 that four of the magazines seven drives had failed, publications sorely needs additional 1541s for in-house use, yet we cant find any to buy. The early 1541s have a mechanism, and the disks often fail to release. This was fixed later when Commodore changed the vendor of the mechanism and adopted the flip-lever Newtronics mechanism. In addition, Commodore made the drives controller board smaller and reduced its chip count compared to the early 1541s, the beige-case Newtronics 1541 was produced from 1984-86. All but the very earliest non-II model 1541s can use either the Alps or Newtronics mechanism, visually, the first models, of the -VIC-1541 denomination, have an off-white color like the VIC-20 and VIC-1540. Then, to match the look of the C64, CBM changed the color to brown-beige. The 1541s numerous shortcomings opened a market for a number of third-party clones of the disk drive, well-known clones are the Oceanic OC-118 a. k. a. Excelerator+, the MSD Super Disk single and dual drives, the Enhancer 2000, the Indus GT, nevertheless, the 1541 became the first disk drive to see widespread use in the home and Commodore sold millions of the units. In 1986, Commodore released the 1541C, a version that offered quieter and slightly more reliable operation. It was replaced in 1988 by the 1541-II, which uses a power supply to provide cooler operation. Later ROM revisions fixed assorted problems, including a bug that made the save-and-replace command unusable
36.
Modem
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A modem is a network hardware device that modulates one or more carrier wave signals to encode digital information for transmission and demodulates signals to decode the transmitted information. The goal is attempting to produce a signal that can be transmitted easily, modems can be used with any means of transmitting analog signals, from light emitting diodes to radio. Modems are generally classified by the amount of data they can send in a given unit of time, usually expressed in bits per second. Modems can also be classified by their rate, measured in baud. The baud unit denotes symbols per second, or the number of times per second the modem sends a new signal. For example, the ITU V.21 standard used audio frequency shift keying with two frequencies, corresponding to two distinct symbols, to carry 300 bits per second using 300 baud. By contrast, the original ITU V.22 standard, which could transmit and receive four distinct symbols, news wire services in the 1920s used multiplex devices that satisfied the definition of a modem. However, the function was incidental to the multiplexing function, so they are not commonly included in the history of modems. S. SAGE modems were described by AT&Ts Bell Labs as conforming to their newly published Bell 101 dataset standard, while they ran on dedicated telephone lines, the devices at each end were no different from commercial acoustically coupled Bell 101,110 baud modems. The 201A and 201B Data-Phones were synchronous modems using two-bit-per-baud phase-shift keying, the famous Bell 103A dataset standard was also introduced by AT&T in 1962. It provided full-duplex service at 300 bit/s over normal phone lines, frequency-shift keying was used, with the call originator transmitting at 1,070 or 1,270 Hz and the answering modem transmitting at 2,025 or 2,225 Hz. The readily available 103A2 gave an important boost to the use of remote low-speed terminals such as the Teletype Model 33 ASR and KSR, AT&T reduced modem costs by introducing the originate-only 113D and the answer-only 113B/C modems. For many years, the Bell System maintained a monopoly on the use of its phone lines, however, the seminal Hush-a-Phone v. FCC case of 1956 concluded it was within the FCCs jurisdiction to regulate the operation of the Bell System. The FCC found that as long as a device was not electronically attached to the system and this led to a number of devices that mechanically connected to the phone through a standard handset. Since most handsets were supplied by Western Electric and thus of a standard design and this type of connection was used for many devices, such as answering machines. Acoustically coupled Bell 103A-compatible 300 bit/s modems were common during the 1970s, well-known models included the Novation CAT and the Anderson-Jacobson, the latter spun off from an in-house project at Stanford Research Institute. An even lower-cost option was the Pennywhistle modem, designed to be built using parts from electronics scrap, in December 1972, Vadic introduced the VA3400, notable for full-duplex operation at 1,200 bit/s over the phone network. Like the 103A, it used different frequency bands for transmit, in November 1976, AT&T introduced the 212A modem to compete with Vadic
37.
RS-232
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In telecommunications, RS-232 is a standard for serial communication transmission of data. It formally defines the signals connecting between a DTE such as a terminal, and a DCE, such as a modem. The RS-232 standard is used in computer serial ports. The standard defines the characteristics and timing of signals, the meaning of signals. The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997. An RS-232 serial port was once a feature of a personal computer, used for connections to modems, printers, mice, data storage, uninterruptible power supplies. However, RS-232 is hampered by low speed, large voltage swing. In modern personal computers, USB has displaced RS-232 from most of its peripheral interface roles, nevertheless, RS-232 devices are still used, especially in industrial machines, networking equipment, and scientific instruments. Interface mechanical characteristics, pluggable connectors and pin identification, functions of each circuit in the interface connector. Standard subsets of interface circuits for selected telecom applications, the standard does not define such elements as the character encoding, the framing of characters, transmission order of bits, or error detection protocols. The character format and transmission bit rate are set by the serial port hardware which may also contain circuits to convert the internal logic levels to RS-232 compatible signal levels. The standard does not define bit rates for transmission, except that it says it is intended for bit rates lower than 20,000 bits per second, RS-232 was first introduced in 1960 by the Electronic Industries Association as a Recommended Standard. The original DTEs were electromechanical teletypewriters, and the original DCEs were modems, when electronic terminals began to be used, they were often designed to be interchangeable with teletypewriters, and so supported RS-232. The C revision of the standard was issued in 1969 in part to accommodate the electrical characteristics of these devices, the resulting common problems were non-standard pin assignment of circuits on connectors, and incorrect or missing control signals. The lack of adherence to the standards produced a thriving industry of breakout boxes, patch boxes, test equipment, books, a common deviation from the standard was to drive the signals at a reduced voltage. Some manufacturers therefore built transmitters that supplied +5 V and −5 V, later personal computers started to make use of the standard so that they could connect to existing equipment. For many years, an RS-232-compatible port was a feature for serial communications, such as modem connections. It remained in use into the late 1990s
38.
Easter egg (media)
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An Easter egg is an intentional inside joke, a hidden message, or a secret feature of an interactive work. The name is used to evoke the idea of a traditional Easter egg hunt, while not the first use of an hidden message in a work, the origin of the term Easter egg to describe these originated from the 1979 video game, Adventure for the Atari 2600. The game was programmed by Atari employee Warren Robinett, at the time, Atari would not include programmers names in the games credits, fearing that competitors would attempt to steal away their employees. Robinett had not told anyone at Atari about this by the time he left the company, shortly after his departure, the Gray Dot and his message was discovered by a player, who wrote their discovery into Atari. Ataris management initially wanted to reprogram and rerelease the game to remove the message, Robinetts addition of his name to Adventure is recognized as the first well-known Easter egg, as well as the origin of the term. However, Robinetts Easter egg is not the first to be implemented, in 2004, an earlier Easter egg was found in Video Whizball, a 1978 game for the Fairchild Channel F system, displaying programmer Bradley Reid-Selths surname. According to research by Ed Fries, the first known Easter egg in arcade games came from Starship 1, programmed by Ron Milner and released in 1977, by triggering the cabinets controls in the right order, the player could get the message Hi Ron. Displayed to them on the screen, since Adventure, there has been a long history of video game developers including Easter eggs in their games. Sometimes the intent was to communicate with the player, sometimes it was a way of getting even with management for a slight, for example, Robinetts first egg was included because he wanted credit for programming the game, which was not customarily included at the time. Video game cheat codes, such as the Konami Code, are a type of Easter egg. More elaborate Easter eggs include secret levels and developers rooms, fully functional yet hidden areas of the game, developers rooms often include inside jokes from the fandom or development team, and differ from a debug room in that they are specifically intended for the player to find. Some games even include hidden sub-games as Easter eggs, in 1993s acclaimed LucasArts video game Day of the Tentacle, the original game Maniac Mansion from 1987 can be played in its full version by using a home computer in one characters room. In computer software, Easter eggs are secret responses that occur as a result of a set of commands. The results can vary from a printed message or image. This same behavior occurred on the RSTS/E operating system, where TECO will provide this response, other Unix operating systems respond to why with why not. Many personal computers have more elaborate eggs hidden in ROM, including lists of the developers names, political exhortations, snatches of music. Easter eggs in the 1997 version of Microsoft Office include a flight simulator in Microsoft Excel. The Debian operating systems package tool apt-get has an Easter egg involving an ASCII cow when variants on apt-get moo are typed into the shell, an Easter egg is found on all Microsoft Windows operating systems before XP
39.
PAL
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Phase Alternating Line is a colour encoding system for analogue television used in broadcast television systems in most countries broadcasting at 625-line /50 field per second. Other common colour encoding systems are NTSC and SECAM, all the countries using PAL are currently in process of conversion or have already converted standards to DVB, ISDB or DTMB. This page primarily discusses the PAL colour encoding system, the articles on broadcast television systems and analogue television further describe frame rates, image resolution and audio modulation. To overcome NTSCs shortcomings, alternative standards were devised, resulting in the development of the PAL, the goal was to provide a colour TV standard for the European picture frequency of 50 fields per second, and finding a way to eliminate the problems with NTSC. PAL was developed by Walter Bruch at Telefunken in Hannover, Germany, with important input from Dr. Kruse, the format was patented by Telefunken in 1962, citing Bruch as inventor, and unveiled to members of the European Broadcasting Union on 3 January 1963. When asked, why the system was named PAL and not Bruch the inventor answered that a Bruch system would not have sold very well. The first broadcasts began in the United Kingdom in June 1967, the one BBC channel initially using the broadcast standard was BBC2, which had been the first UK TV service to introduce 625-lines in 1964. Telefunken PALcolor 708T was the first PAL commercial TV set and it was followed by Loewe-Farbfernseher S920 & F900. Telefunken was later bought by the French electronics manufacturer Thomson, Thomson also bought the Compagnie Générale de Télévision where Henri de France developed SECAM, the first European Standard for colour television. The term PAL was often used informally and somewhat imprecisely to refer to the 625-line/50 Hz television system in general, accordingly, DVDs were labelled as PAL or NTSC even though technically the discs do not carry either PAL or NTSC composite signal. CCIR 625/50 and EIA 525/60 are the names for these standards, PAL. Both the PAL and the NTSC system use a quadrature amplitude modulated subcarrier carrying the chrominance information added to the video signal to form a composite video baseband signal. The frequency of this subcarrier is 4.43361875 MHz for PAL and NTSC4.43, the SECAM system, on the other hand, uses a frequency modulation scheme on its two line alternate colour subcarriers 4.25000 and 4.40625 MHz. Early PAL receivers relied on the eye to do that cancelling, however. The effect is that phase errors result in changes, which are less objectionable than the equivalent hue changes of NTSC. In any case, NTSC, PAL, and SECAM all have chrominance bandwidth reduced greatly compared to the luminance signal. The 4.43361875 MHz frequency of the carrier is a result of 283.75 colour clock cycles per line plus a 25 Hz offset to avoid interferences. Since the line frequency is 15625 Hz, the carrier frequency calculates as follows,4.43361875 MHz =283.75 ×15625 Hz +25 Hz
40.
NTSC
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The first NTSC standard was developed in 1941 and had no provision for color. In 1953 a second NTSC standard was adopted, which allowed for television broadcasting which was compatible with the existing stock of black-and-white receivers. NTSC was the first widely adopted broadcast color system and remained dominant until 1997, North America, parts of Central America, and South Korea are adopting or have adopted the ATSC standards, while other countries are adopting or have adopted other standards instead of ATSC. After nearly 70 years, the majority of over-the-air NTSC transmissions in the United States ceased on January 1,2010, the majority of NTSC transmissions ended in Japan on July 24,2011, with the Japanese prefectures of Iwate, Miyagi, and Fukushima ending the next year. In March 1941, the committee issued a standard for black-and-white television that built upon a 1936 recommendation made by the Radio Manufacturers Association. Technical advancements of the side band technique allowed for the opportunity to increase the image resolution. The NTSC selected 525 scan lines as a compromise between RCAs 441-scan line standard and Philcos and DuMonts desire to increase the number of lines to between 605 and 800. The standard recommended a frame rate of 30 frames per second, other standards in the final recommendation were an aspect ratio of 4,3, and frequency modulation for the sound signal. In January 1950, the committee was reconstituted to standardize color television, in December 1953, it unanimously approved what is now called the NTSC color television standard. The compatible color standard retained full backward compatibility with existing black-and-white television sets, Color information was added to the black-and-white image by introducing a color subcarrier of precisely 315/88 MHz. These changes amounted to 0.1 percent and were tolerated by existing television receivers. The FCC had briefly approved a different color standard, starting in October 1950. However, this standard was incompatible with black-and-white broadcasts and it used a rotating color wheel, reduced the number of scan lines from 525 to 405, and increased the field rate from 60 to 144, but had an effective frame rate of only 24 frames per second. CBS rescinded its system in March 1953, and the FCC replaced it on December 17,1953, with the NTSC color standard, later that year, the improved TK-41 became the standard camera used throughout much of the 1960s. The NTSC standard has been adopted by countries, including most of the Americas. With the advent of television, analog broadcasts are being phased out. Most US NTSC broadcasters were required by the FCC to shut down their analog transmitters in 2009, low-power stations, Class A stations and translators were required to shut down by 2015. NTSC color encoding is used with the System M television signal, each frame is composed of two fields, each consisting of 262.5 scan lines, for a total of 525 scan lines
