1.
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 By the end of the 1980s, 5¼-inch disks had been superseded by 3½-inch disks, by the mid-1990s, 5¼-inch drives had virtually disappeared, as the 3½-inch disk became the predominant floppy disk.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
2.
ROM cartridge
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ROM cartridges can be used to load software such as video games or other application programs. The cartridge slot could also be used for additions, for example speech synthesis. Some cartridges had battery-backed static random-access memory, allowing a user to save data such as game progress or scores between uses, an advantage for the manufacturer was the relative security of the software in cartridge form, which was difficult for end users to replicate. However, cartridges were expensive to manufacture compared to making a floppy disk or CD-ROM, as disk drives became more common and software expanded beyond the practical limits of ROM size, cartridge slots disappeared from later game consoles and personal computers. Cartridges are still used today with handheld gaming consoles such as the Nintendo DS, Nintendo 3DS, due to its widespread usage for video gaming, ROM cartridges were often colloquially referred to as a game cartridge. ROM cartridges were popularized by early home computers which featured a special bus port for the insertion of cartridges containing software in ROM. Notable computers using cartridges in addition to magnetic media were the Commodore VIC-20 and 64, MSX standard, the Atari 8-bit family, the Texas Instruments TI-99/4A, some arcade system boards, such as Capcoms CP System and SNKs Neo Geo, also used ROM cartridges. The modern take on game cartridges was invented by Jerry Lawson as part of the Fairchild Channel F home console in 1976, the cartridge approach gained more popularity with the Atari 2600 released the following year. From the late 1970s to mid-1990s, the majority of video game systems were cartridge-based. As compact disc technology came to be used widely for data storage, Nintendo remained the lone hold-out, using cartridges for their Nintendo 64 system, the company did not transition to optical media until 2001s GameCube. SNK still released games on the cartridge based Neo Geo until 2004, ROM cartridges can not only carry software, but additional hardware expansion as well. Examples include the Super FX coprocessor chip in some Super NES game paks, micro Machines 2 on the Genesis/Mega Drive used a custom J-Cart cartridge design by Codemasters which incorporated two additional gamepad ports. This allowed players to have up to four gamepads connected to the console without the need for an additional multi-controller adapter, the ROM cartridge slot principle continues in various mobile devices, thanks to the development of high density low-cost flash memory. For example, a GPS navigation device might allow user updates of maps by inserting a memory chip into an expansion slot. An E-book reader can store the text of several books on a flash chip. Personal computers may allow the user to boot and install a system off a USB flash drive instead of CD ROM or floppy disks. Digital cameras with flash drive slots allow users to exchange cards when full. Storing software on ROM cartridges has a number of advantages over other methods of storage like floppy disks, software run directly from ROM typically uses less RAM, leaving memory free for other processes
3.
Emulator
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In computing, an emulator is hardware or software that enables one computer system to behave like another computer system. An emulator typically enables the host system to run software or use peripheral devices designed for the guest system, emulation refers to the ability of a computer program in an electronic device to emulate another program or device. Many printers, for example, are designed to emulate Hewlett-Packard LaserJet printers because so much software is written for HP printers. If a non-HP printer emulates an HP printer, any software written for a real HP printer will also run in the non-HP printer emulation and produce equivalent printing. Since at least the 1990s until today, some video game enthusiasts use emulators to play 1980s arcade games using the original 1980s programming code, a hardware emulator is an emulator which takes the form of a hardware device. In a theoretical sense, the Church-Turing thesis implies that any operating environment can be emulated within any other environment. However, in practice, it can be difficult, particularly when the exact behavior of the system to be emulated is not documented and has to be deduced through reverse engineering. Emulation is a strategy in digital preservation to combat obsolescence, emulation addresses the original hardware and software environment of the digital object, and recreates it on a current machine. The emulator allows the user to have access to any kind of application or operating system on a current platform and he further states that this should not only apply to out of date systems, but also be upwardly mobile to future unknown systems. Potentially better graphics quality than original hardware, potentially additional features original hardware didnt have. Emulators maintain the look, feel, and behavior of the digital object. Despite the original cost of developing an emulator, it may prove to be the more cost efficient solution over time, many emulators have already been developed and released under GNU General Public License through the open source environment, allowing for wide scale collaboration. Emulators allow software exclusive to one system to be used on another, for example, a PlayStation 2 exclusive video game could be played on a PC using an emulator. This is especially useful when the system is difficult to obtain. Copyright laws are not yet in effect to address saving the documentation and these protections make it more difficult to design emulators, since they must be accurate enough to avoid triggering the protections, whose effects may not be obvious. Emulators require better hardware than the system has. Because of its use of digital formats, new media art relies heavily on emulation as a preservation strategy. The paradox is that the emulation and the emulator have to be made to work on future computers, emulation techniques are commonly used during the design and development of new systems
4.
Field-programmable gate array
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A field-programmable gate array is an integrated circuit designed to be configured by a customer or a designer after manufacturing – hence field-programmable. The FPGA configuration is generally specified using a description language. Logic blocks can be configured to perform complex functions, or merely simple logic gates like AND. In most FPGAs, logic blocks also include elements, which may be simple flip-flops or more complete blocks of memory. Contemporary field-programmable gate arrays have large resources of logic gates and RAM blocks to implement complex digital computations, as FPGA designs employ very fast I/Os and bidirectional data buses, it becomes a challenge to verify correct timing of valid data within setup time and hold time. Floor planning enables resources allocation within FPGAs to meet time constraints. FPGAs can be used to implement any logical function that an ASIC could perform, some FPGAs have analog features in addition to digital functions. Fairly common are differential comparators on input pins designed to be connected to differential signaling channels, the FPGA industry sprouted from programmable read-only memory and programmable logic devices. PROMs and PLDs both had the option of being programmed in batches in a factory or in the field, however, programmable logic was hard-wired between logic gates. In the late 1980s, the Naval Surface Warfare Center funded an experiment proposed by Steve Casselman to develop a computer that would implement 600,000 reprogrammable gates, Casselman was successful and a patent related to the system was issued in 1992. Some of the foundational concepts and technologies for programmable logic arrays, gates. Xilinx co-founders Ross Freeman and Bernard Vonderschmitt invented the first commercially viable field-programmable gate array in 1985 – the XC2064, the XC2064 had programmable gates and programmable interconnects between gates, the beginnings of a new technology and market. The XC2064 had 64 configurable logic blocks, with two three-input lookup tables, more than 20 years later, Freeman was entered into the National Inventors Hall of Fame for his invention. Altera and Xilinx continued unchallenged and quickly grew from 1985 to the mid-1990s, by 1993, Actel was serving about 18 percent of the market. By 2010, Altera, Actel and Xilinx together represented approximately 77 percent of the FPGA market, the 1990s were an explosive period of time for FPGAs, both in sophistication and the volume of production. In the early 1990s, FPGAs were primarily used in telecommunications, by the end of the decade, FPGAs found their way into consumer, automotive, and industrial applications. This work mirrors the architecture by Ron Perlof and Hana Potash of Burroughs Advanced Systems Group which combined a reconfigurable CPU architecture on a chip called the SB24. That work was done in 1982, the Atmel FPSLIC is another such device, which uses an AVR processor in combination with Atmels programmable logic architecture
5.
Xilinx
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Xilinx, Inc. is an American technology company, primarily a supplier of programmable logic devices. It is known for inventing the field-programmable gate array and as the first semiconductor company with a fabless manufacturing model, major FPGA product families include Virtex, Kintex and Artix, and the retired Spartan series. Major computer software includes Xilinx ISE and Vivado Design Suite, Ross Freeman, Bernard Vonderschmitt, and James V Barnett II, who all had worked for integrated circuit and solid-state device manufacturer Zilog Corp, founded Xilinx in 1984. While working for Zilog, Freeman wanted to create chips that acted like a blank tape, at the time, the concept was paradigm changing. Big semiconductor manufacturers were enjoying strong profits by producing massive volumes of generic circuits, designing and manufacturing dozens of different circuits for specific markets offered lower profit margins and required greater manufacturing complexity. What became known as the FPGA would allow circuits produced in quantity to be tailored by individual market segments, Freeman failed to convince Zilog to invest in creating the FPGA to chase what was only a $100 million market at the time. Freeman and Barnett left Zilog and teamed up with their 60-year-old ex-colleague Bernard Vonderschmitt to raise $4.5 million in funding to design the first commercially viable FPGA. They incorporated the company in 1984 and began selling its first product by 1985, by late 1987 the company had raised more than $18 million in venture capital and generated revenues at an annualized rate of nearly $14 million. As demand for programmable logic continued to grow, so did Xilinxs revenues, from 1988 to 1990, the companys revenue grew each year from $30 million to $50 million to $100 million. During this time period, the company which had been providing funding to Xilinx, as a result, Xilinx dissolved the deal with MMI and went public on the NASDAQ in 1989. The company also moved to a 144, 000-square-foot plant in San Jose, California in order to pace with demand from companies like HP. IBM and Sun Microsystems who were buying large quantities from Xilinx, Xilinx competitors emerged in the FPGA market in the mid-1990s. Despite the competition, Xilinxs sales grew to $135 million in 1991, $178 million in 1992, the company reached $550 million in revenue in 1995, one decade after having sold its first product. According to market research firm iSuppli, Xilinx has held the lead in programmable logic device market share since the late 1990s, over the years, Xilinx expanded operations to India, Asia and Europe. Xilinxs sales rose from $560 million in 1996 to $2.2 billion by the end of its fiscal year 2013 and these targeted design platforms are an alternative to costly application-specific integrated circuits and application-specific standard products. The company has expanded its product portfolio since its founding, Xilinx sells a broad range of FPGAs, complex programmable logic devices, design tools, intellectual property and reference designs. Xilinx also has a services and training program. The companys products have been recognized by EE Times, EDN and others for innovation, in addition to Zynq-7000, Xilinx product lines include the Virtex, Kintex and Artix series, each including configurations and models optimized for different applications
6.
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
7.
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
8.
Commodore REU
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Commodores RAM Expansion Unit range of external RAM add-ons for their Commodore 64/128 home computers was announced at the same time as the C128. The REUs came in three models, initially the 1700 and 1750, and later the 1764. By the time of the 1985 CES show in Chicago, the engineers were able to display a spinning globe of the earth as a demonstration of Direct Memory Access by the new REU units. The REU hardware was designed by Frank Palia and the dedicated Integrated Circuit was designed by Victor Andrade. Fred Bowen and Terry Ryan adapted the kernel and Basic to accommodate the REU natively, additionally, the C128s built-in BASIC7.0 had three statements, STASH, FETCH, and SWAP, for storing and retrieving data from the REU. Officially, only the 1700 and 1750 were supported on the C128, the 256 kB model, the 1764, was released for the C64 at the same time. There were only minor differences between the three models, the 1700 utilizes sixteen 4164 64kx1 DRAMs, the 1764 has eight 41256 256kx1 DRAMs, and the 1750 has sixteen 41256 DRAMs. Some dealers unbundled the 1764 and the supply in order to sell the power supply to C64 users. During the late 1980s, there was a shortage of DRAM caused by the Reagan Administration enacting anti-dumping restrictions on Japanese manufacturers, thus 1750s were rare, however it was comparatively easy to upgrade a 1700 or 1764 to 512 kB. Several firms did this commercially, either selling upgraded units or upgrading customer-supplied units, in the early 1990s, DIY modification schemes to increase the capacity of an REU to one megabyte or higher appeared on various online services. The 1700s circuit board was identical to that of the 1750, on the 1750 and 1764, this trace was cut. The 1700 and 1750 had a resistor at position R4 that, according to Commodore engineer Fred Bowen, compensated for subtle differences in the port on the C64. Bowen and other CBM engineers recommended against using a 1764 with a C128 unless the resistor was added, or a 1700/1750 with a C64 unless the resistor was removed. It was possible to check for the presence of a 1750 by reading memory address $DF00s bit 4, which was 1 on a 1750, and 0 on a 1700 or 1764. However, since this procedure would not distinguish between a 1700 and a 1764, many programmers wrote to the RAM itself to find out the amount of memory installed, very little software made use of the REUs. Additionally, many commercial programs simply overwrote the memory space occupied by the RAM disk software. GEOS as well as other programs even used the REU for quick memory transfers within the host machines main memory by storing a memory block into the REU and then fetching it back to another location. Due to its speed relative to Commodores floppy drives or even the commercially available hard drives
9.
Action Replay
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Action Replay is the brand name of a cheating device created by Datel. The Action Replay is available for many gaming systems including the Nintendo DS, Nintendo DSi, PlayStation Portable, PlayStation 2, GameCube, Game Boy Advance, and the Xbox. Typical cheating options include power-ups, level warping, and display of game data. Some other typical features include, Infinite lives, invulnerability, permanent power-ups, no collision detection, walk through walls, one-hit kills, super-high jumps, infinite money, the ability to download, upload, import and export saved games to the Internet or a storage device. Allowing the player to save the state to disk, so that the game can be restarted from that point even if it does not support saving. Loading of third-party applications/games, not backup copies of retail games, power-Saves by Action Replay are a related series of video-game cheat devices. Power-Saves are available for systems such as the Wii on an SD card. The card has a grabber, a trainer, and a slowdown feature and it can also interrupt the current game or save it to disk. Models running firmware 4.0 and beyond use EEP-ROM instead of ROM, in December 1998, Datel released a version for Windows 95/98. Action Replay DS 3DS/DSi/DS/Lite Compatible Nintendo 3DS, Nintendo 3DS XL Action Replay Power Saves for 3DS, the Action Replay Power Saves for 3DS can alter saves of 3DS games and has some codes for 3DS games
10.
The Final Cartridge III
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The Final Cartridge III was a popular extension cartridge which was created for the Commodore 64 and Commodore 128, produced by the Dutch company Riska B. V. It offered a fast loader, increasing the speeds of the drive. The cartridge featured a button and a freeze button, as well as a LED that indicated whether or not the module was active. The cartridge featured a Final Kill option which disabled the cartridges functionality and this was needed as some software, particularly games, were incompatible with fast-loaders, disabling the cartridge meant it never needed to be removed. One of the features of the cartridge was its GUI. Unless RUN/STOP key was held down during power-on or reset, the cartridge presented a graphical WIMP desktop, the graphical look of the desktop was borrowed from AmigaOS1. x. It was possible to load new GUI-based utilities from disk or tape, of the tools in the cartridge ROM, the most useful were a text editor, a disk file management utility, a calculator, and an alarm clock. A big selling point was the disk and tape turbo feature, which was available for most commands, the BASIC commands also allowed to return to the GUI desktop mode, or start the machine-language monitor. The freezer feature allowed to save the contents to disk to be resumed at later point. It also allowed the use of some rudimentary game cheating functionality, the freezer also allowed access to the machine-language monitor. The FC3 can be combined well with a SD2IEC-Floppy, because his Fastloader stays alive in File-Browsers like CBM or SD2BRWSE. Also, user have the very good FC3 F-key commands for changing directories on the SD-Card or loading files without the need of typing anything, therefore, the combination FC3 and SD2IEC complement each other very well. ISEPIC Trilogic Expert Cartridge Project64 etext of The Final Cartridge III manual Photos and Information about the Final Cartridge III
11.
Commodore 64 software
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The Commodore 64 amassed a large software library of nearly 10,000 commercial titles, covering most genres from games to business applications, and many others. Like most computers from the late 1970s and 1980s, the Commodore 64 came with a version of the BASIC programming language and it was used for both writing software and for performing the duties of an operating system such as loading software, formatting disks, etc. Unfortunately, the onboard BASIC programming language offered no way to tap the machines advanced graphics. Commodore had an implementation of BASIC but chose to ship the C64 with the same BASIC2.0 used in the VIC-20 to minimize cost. This, however, did not stop countless people making thousands of programs in the BASIC V2 language, aside from games and office applications such as word processors, spreadsheets, and database programs, the C64 was well equipped with development tools from Commodore as well as third-party vendors. Various assembler solutions were available, the MIKRO assembler came in ROM cartridge form, the PAL Assembler by Brad Templeton was also popular. Several companies sold BASIC compilers, C compilers and Pascal compilers, the likely most popular entertainment oriented development suite was the ShootEm-Up Construction Kit, affectionately known as SEUCK. SEUCK allowed those non-skilled in programming to create original, professional-looking shooting games, garry Kitchens Gamemaker and Arcade Game Construction Kit also allowed non-programmers to create simple games with little effort. Text adventure game tools included The Quill and Graphic Adventure Creator development suites, the Pinball Construction Set gave users a pinball machine to design. Software development on the Commodore 64 never really stopped, Tools such as PuCrunch, an LZ77 data and executable self extracting compression program, are also available released under GNU LGPL. Sprite editors like Sprite Pad allow you to design C64 Sprites, goatTracker allows you to write music using modern OSs and uses the ReSID engine. Using CodeNet it is possible to transfer and execute programs to a C64 via a TCP/IP network cable from a PC, although this does require an Ethernet adapter on the C64 such as Individual Computers RR-Net or an appropriate version of Gideon Zweijtzers 1541u. C64 Codebase and C64 Wiki are good sources of information for programming on the Commodore 64, Fairlight provide an extensive list of tools to help, as do Lemon64. The MOS Technology 6581 SID is the chip for the C64. A most popular software tool for the C64, was Kawasaki Synthesizer created in 1983. By 1985 games were estimated to make up 60 to 70% of Commodore 64 software and its large installed user base encouraged commercial companies to flood the market with game software, even up until Commodores demise in 1994. In total over 23,000 unique game titles exist for the Commodore 64, Commodore did not publish many games itself for the C64, instead releasing game cartridges primarily from their failed MAX Machine for the C64. Commodore included an Ultimax mode in the Commodore 64s hardware, which allowed the computer to emulate a MAX machine for this purpose, however, aside from the initial Commodore cartridges, very few cartridge-based games were released for the Commodore
12.
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
13.
Secure Digital
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Secure Digital is a non-volatile memory card format developed by the SD Card Association for use in portable devices. The standard was introduced in August 1999 by joint efforts between SanDisk, Panasonic and Toshiba as an improvement over MultiMediaCards, and has become the industry standard. The three companies formed SD-3C, LLC, a company that licenses and enforces intellectual property rights associated with SD memory cards and SD host, the companies also formed the SD Association, a non-profit organization, in January 2000 to promote and create SD Card standards. SDA today has about 1,000 member companies, the SDA uses several trademarked logos owned and licensed by SD-3C to enforce compliance with its specifications and assure users of compatibility. There are many combinations of factors and device families, although as of 2016. Secure Digital includes four card families available in three different sizes, the four families are the original Standard-Capacity, the High-Capacity, the eXtended-Capacity, and the SDIO, which combines input/output functions with data storage. The three form factors are the size, the mini size, and the micro size. Electrically passive adapters allow a card to fit and function in a device built for a larger card. The SD cards small footprint is a storage medium for smaller, thinner. The second-generation Secure Digital card was developed to improve on the MultiMediaCard standard, which continued to evolve, Secure Digital changed the MMC design in several ways, Asymmetrical slots in the sides of the SD card prevent inserting it upside down. Most SD cards are 2.1 mm thick, compared to 1.4 mm for MMCs. The SD specification defines a card called Thin SD with a thickness of 1.4 mm, the cards electrical contacts are recessed beneath the surface of the card, protecting them from contact with a users fingers. The SD specification envisioned capacities and transfer rates exceeding those of MMC, for a comparison table, see below. While MMC uses a pin for data transfers, the SD card added a four-wire bus mode for higher data rates. The SD card added Content Protection for Recordable Media security circuitry for digital rights management content-protection, full-size SD cards do not fit into the slimmer MMC slots, and other issues also affect the ability to use one format in a host device designed for the other. The Secure Digital High Capacity format, announced in January 2006 and defined in version 2.0 of the SD specification, the SDHC trademark is licensed to ensure compatibility. SDHC cards are physically and electrically identical to standard-capacity SD cards, Version 2.0 also introduces a High-speed bus mode for both SDSC and SDHC cards, which doubles the original Standard Speed clock to produce 25 MB/s. SDHC host devices are required to accept older SD cards, however, older host devices do not recognize SDHC or SDXC memory cards, although some devices can do so through a firmware upgrade
14.
Megabyte
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The megabyte is a multiple of the unit byte for digital information. Its recommended unit symbol is MB, but sometimes MByte is used, the unit prefix mega is a multiplier of 1000000 in the International System of Units. Therefore, one megabyte is one million bytes of information and this definition has been incorporated into the International System of Quantities. However, in the computer and information fields, several other definitions are used that arose for historical reasons of convenience. A common usage has been to one megabyte as 1048576bytes. However, most standards bodies have deprecated this usage in favor of a set of binary prefixes, less common is a convention that used the megabyte to mean 1000×1024 bytes. The megabyte is commonly used to measure either 10002 bytes or 10242 bytes, the interpretation of using base 1024 originated as a compromise technical jargon for the byte multiples that needed to be expressed by the powers of 2 but lacked a convenient name. As 1024 approximates 1000, roughly corresponding to the SI prefix kilo-, in 1998 the International Electrotechnical Commission proposed standards for binary prefixes requiring the use of megabyte to strictly denote 10002 bytes and mebibyte to denote 10242 bytes. By the end of 2009, the IEC Standard had been adopted by the IEEE, EU, ISO, the Mac OS X10.6 file manager is a notable example of this usage in software. Since Snow Leopard, file sizes are reported in decimal units, base 21 MB =1048576 bytes is the definition used by Microsoft Windows in reference to computer memory, such as RAM. This definition is synonymous with the binary prefix mebibyte. Mixed 1 MB =1024000 bytes is the used to describe the formatted capacity of the 1.44 MB3. 5inch HD floppy disk. Semiconductor memory doubles in size for each address lane added to an integrated circuit package, the capacity of a disk drive is the product of the sector size, number of sectors per track, number of tracks per side, and the number of disk platters in the drive. Changes in any of these factors would not usually double the size, sector sizes were set as powers of two for convenience in processing. It was an extension to give the capacity of a disk drive in multiples of the sector size, giving a mix of decimal. Depending on compression methods and file format, a megabyte of data can roughly be, a 4 megapixel JPEG image with normal compression. Approximately 1 minute of 128 kbit/s MP3 compressed music,6 seconds of uncompressed CD audio. A typical English book volume in plain text format, the human genome consists of DNA representing 800 MB of data
15.
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
16.
CP/M
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Initially confined to single-tasking on 8-bit processors and no more than 64 kilobytes of memory, later versions of CP/M added multi-user variations and were migrated to 16-bit processors. The combination of CP/M and S-100 bus computers was loosely patterned on the MITS Altair and this computer platform was widely used in business through the late 1970s and into the mid-1980s. CP/M increased the size for both hardware and software by greatly reducing the amount of programming required to install an application on a new manufacturers computer. An important driver of innovation was the advent of low-cost microcomputers running CP/M, as independent programmers and hackers bought them. CP/M was displaced by MS-DOS soon after the 1981 introduction of the IBM PC, manufacturers of CP/M-compatible systems customized portions of the operating system for their own combination of installed memory, disk drives, and console devices. CP/M would also run on based on the Zilog Z80 processor since the Z80 was compatible with 8080 code. CP/M used the 7-bit ASCII set, the other 128 characters made possible by the 8-bit byte were not standardized. For example, one Kaypro used them for Greek characters, WordStar used the 8th bit as an end-of-word marker. The BIOS and BDOS were memory-resident, while the CCP was memory-resident unless overwritten by an application, a number of transient commands for standard utilities were also provided. The transient commands resided in files with the extension. COM on disk, the BIOS directly controlled hardware components other than the CPU and main memory. It contained functions such as input and output and the reading and writing of disk sectors. The BDOS implemented the CP/M file system and some input/output abstractions on top of the BIOS, the CCP took user commands and either executed them directly or loaded and started an executable file of the given name. Third-party applications for CP/M were also essentially transient commands, the BDOS, CCP and standard transient commands were the same in all installations of a particular revision of CP/M, but the BIOS portion was always adapted to the particular hardware. Adding memory to a computer, for example, meant that the CP/M system had to be reinstalled with an updated BIOS capable of addressing the additional memory, a utility was provided to patch the supplied BIOS, BDOS and CCP to allow them to be run from higher memory. Once installed, the system was stored in reserved areas at the beginning of any disk which would be used to boot the system. On start-up, the bootloader would load the system from the disk in drive A. By modern standards CP/M was primitive, owing to the constraints on program size. With version 1.0 there was no provision for detecting a changed disk, if a user changed disks without manually rereading the disk directory the system would write on the new disk using the old disks directory information, ruining the data stored on the disk
17.
GEOS (8-bit operating system)
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GEOS is a discontinued operating system from Berkeley Softworks. Originally designed for the Commodore 64 and released in 1986, it provides a user interface for this popular 8-bit computer. GEOS closely resembles early versions of the classic Mac OS and includes a word processor. A December 1987 survey by the Commodore-dedicated magazine Compute. s Gazette found that half of its readers used GEOS. For many years, Commodore bundled GEOS with its redesigned and cost-reduced C64, at its peak, GEOS was the third-most-popular microcomputer operating system in the world in terms of units shipped, trailing only MS-DOS and Mac OS. Enhanced versions of GEOS later became available in 1987 for the Commodore 128, a lesser-known version was also released for the Commodore Plus/4. Unlike many pieces of software for the C64 and C128, GEOS takes full advantage of many of the add-ons. Commodores 1351 mouse is supported by GEOS, as are its various RAM expansion units, GEOS128 also fully supports the C128s 640×200 high-resolution VDC display mode through a compatible RGB monitor. The C64 version of GEOS incorporates a built-in fast loader, called diskTurbo, GEOS is the first Commodore software that could use a floppy disk as swap space or virtual memory. GEOS128 can take advantage of the C128s enhanced burst mode in conjunction with the 1571 and 1581 drives, the Commodore version of GEOS uses a copy protection scheme that renders users disks unbootable if it detects that the disk has been illegally duplicated. This ability to print to high-end printers was a factor in making GEOS a desktop publishing platform. The Apple II version of GEOS was released as freeware in August 2003, the Commodore 64/128 versions followed in February 2004. The Apple II version is available for download from Breadbox. The latest GEOS desktop suite for IBM PC compatibles is Breadbox Ensemble, revivals were seen in the OmniGo handhelds, Brother GeoBook line of laptop-appliances, and the NewDeal Office package for PCs. Related code found its way to earlier Zoomer PDAs, creating a lineage to Palm. Nokia used GEOS as an operating system for their Nokia Communicator series. The reverse-engineered source code has been available at Github. Dozens of official and third-party applications and other products were produced for GEOS, the Official GEOS Programmers Reference Guide
18.
USB
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It is currently developed by the USB Implementers Forum. USB was designed to standardize the connection of peripherals to personal computers. It has become commonplace on other devices, such as smartphones, PDAs, USB has effectively replaced a variety of earlier interfaces, such as serial ports and parallel ports, as well as separate power chargers for portable devices. Also, there are 5 modes of USB data transfer, in order of increasing bandwidth, Low Speed, Full Speed, High Speed, SuperSpeed, USB devices have some choice of implemented modes, and USB version is not a reliable statement of implemented modes. Modes are identified by their names and icons, and the specifications suggests that plugs, unlike other data buses, USB connections are directed, with both upstream and downstream ports emanating from a single host. This applies to power, with only downstream facing ports providing power. Thus, USB cables have different ends, A and B, therefore, in general, each different format requires four different connectors, a plug and receptacle for each of the A and B ends. USB cables have the plugs, and the corresponding receptacles are on the computers or electronic devices, in common practice, the A end is usually the standard format, and the B side varies over standard, mini, and micro. The mini and micro formats also provide for USB On-The-Go with a hermaphroditic AB receptacle, the micro format is the most durable from the point of view of designed insertion lifetime. The standard and mini connectors have a lifetime of 1,500 insertion-removal cycles. Likewise, the component of the retention mechanism, parts that provide required gripping force, were also moved into plugs on the cable side. A group of seven companies began the development of USB in 1994, Compaq, DEC, IBM, Intel, Microsoft, NEC, a team including Ajay Bhatt worked on the standard at Intel, the first integrated circuits supporting USB were produced by Intel in 1995. The original USB1.0 specification, which was introduced in January 1996, Microsoft Windows 95, OSR2.1 provided OEM support for the devices. The first widely used version of USB was 1.1, the 12 Mbit/s data rate was intended for higher-speed devices such as disk drives, and the lower 1.5 Mbit/s rate for low data rate devices such as joysticks. Apple Inc. s iMac was the first mainstream product with USB, following Apples design decision to remove all legacy ports from the iMac, many PC manufacturers began building legacy-free PCs, which led to the broader PC market using USB as a standard. The USB2.0 specification was released in April 2000 and was ratified by the USB Implementers Forum at the end of 2001.1 specification, the USB3.0 specification was published on 12 November 2008. Its main goals were to increase the transfer rate, decrease power consumption, increase power output. USB3.0 includes a new, higher speed bus called SuperSpeed in parallel with the USB2.0 bus, for this reason, the new version is also called SuperSpeed
19.
VHDL
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VHDL is a hardware description language used in electronic design automation to describe digital and mixed-signal systems such as field-programmable gate arrays and integrated circuits. VHDL can also be used as a general purpose programming language. VHDL was originally developed at the behest of the U. S Department of Defense in order to document the behavior of the ASICs that supplier companies were including in equipment. The idea of being able to simulate the ASICs from the information in this documentation was so attractive that logic simulators were developed that could read the VHDL files. The next step was the development of logic synthesis tools that read the VHDL, a problem not solved by this edition, however, was multi-valued logic, where a signals drive strength and unknown values are also considered. This required IEEE standard 1164, which defined the 9-value logic types, scalar std_logic, Minor changes in the standard added the idea of protected types and removed some restrictions from port mapping rules. In addition to IEEE standard 1164, several child standards were introduced to extend functionality of the language, IEEE standard 1076.2 added better handling of real and complex data types. IEEE standard 1076.3 introduced signed and unsigned types to facilitate arithmetical operations on vectors, IEEE standard 1076.1 provided analog and mixed-signal circuit design extensions. Some other standards support wider use of VHDL, notably VITAL, in June 2006, the VHDL Technical Committee of Accellera approved so called Draft 3.0 of VHDL-2006. While maintaining full compatibility with older versions, this proposed standard provides numerous extensions that make writing and managing VHDL code easier and these changes should improve quality of synthesizable VHDL code, make testbenches more flexible, and allow wider use of VHDL for system-level descriptions. In 2008, Accellera released VHDL4.0 to the IEEE for balloting for inclusion in IEEE 1076-2008, the VHDL standard IEEE 1076-2008 was published in January 2009. The IEEE Standard 1076 defines the VHSIC Hardware Description Language or VHDL, the language has undergone numerous revisions and has a variety of sub-standards associated with it that augment or extend it in important ways. 1076 was and continues to be a milestone in the design of electronic systems, IEEE 1076-1987 First standardized revision of ver 7.2 of the language from the United States Air Force. IEEE 1076-1993 Significant improvements resulting from years of feedback. Probably the most widely used version with the greatest vendor tool support, introduces the use of protected types. IEEE 1076-2002 Minor revision of 1076-2000, rules with regard to buffer ports are relaxed. IEC 61691-1-1,2004 IEC adoption of IEEE 1076-2002 IEEE 1076-2008 Major revision released on 2009-01-26, among other changes, this standard introduces the use of external names. Such a model is processed by a program, only if it is part of the logic design
20.
Open-source model
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Open-source software may be developed in a collaborative public manner. According to scientists who studied it, open-source software is a prominent example of open collaboration, a 2008 report by the Standish Group states that adoption of open-source software models has resulted in savings of about $60 billion per year to consumers. In the early days of computing, programmers and developers shared software in order to learn from each other, eventually the open source notion moved to the way side of commercialization of software in the years 1970-1980. In 1997, Eric Raymond published The Cathedral and the Bazaar and this source code subsequently became the basis behind SeaMonkey, Mozilla Firefox, Thunderbird and KompoZer. Netscapes act prompted Raymond and others to look into how to bring the Free Software Foundations free software ideas, the new term they chose was open source, which was soon adopted by Bruce Perens, publisher Tim OReilly, Linus Torvalds, and others. The Open Source Initiative was founded in February 1998 to encourage use of the new term, a Microsoft executive publicly stated in 2001 that open source is an intellectual property destroyer. I cant imagine something that could be worse than this for the software business, IBM, Oracle, Google and State Farm are just a few of the companies with a serious public stake in todays competitive open-source market. There has been a significant shift in the corporate philosophy concerning the development of FOSS, the free software movement was launched in 1983. In 1998, a group of individuals advocated that the free software should be replaced by open-source software as an expression which is less ambiguous. Software developers may want to publish their software with an open-source license, the Open Source Definition, notably, presents an open-source philosophy, and further defines the terms of usage, modification and redistribution of open-source software. Software licenses grant rights to users which would otherwise be reserved by law to the copyright holder. Several open-source software licenses have qualified within the boundaries of the Open Source Definition, the open source label came out of a strategy session held on April 7,1998 in Palo Alto in reaction to Netscapes January 1998 announcement of a source code release for Navigator. They used the opportunity before the release of Navigators source code to clarify a potential confusion caused by the ambiguity of the free in English. Many people claimed that the birth of the Internet, since 1969, started the open source movement, the Free Software Foundation, started in 1985, intended the word free to mean freedom to distribute and not freedom from cost. Since a great deal of free software already was free of charge, such software became associated with zero cost. The Open Source Initiative was formed in February 1998 by Eric Raymond and they sought to bring a higher profile to the practical benefits of freely available source code, and they wanted to bring major software businesses and other high-tech industries into open source. Perens attempted to open source as a service mark for the OSI. The Open Source Initiatives definition is recognized by governments internationally as the standard or de facto definition, OSI uses The Open Source Definition to determine whether it considers a software license open source
21.
GNU General Public License
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The GNU General Public License is a widely used free software license, which guarantees end users the freedom to run, study, share and modify the software. The license was written by Richard Stallman of the Free Software Foundation for the GNU Project. The GPL is a license, which means that derivative work can only be distributed under the same license terms. This is in distinction to permissive free licenses, of which the BSD licenses. GPL was the first copyleft license for general use, historically, the GPL license family has been one of the most popular software licenses in the free and open-source software domain. Prominent free software licensed under the GPL include the Linux kernel. In 2007, the version of the license was released to address some perceived problems with the second version that were discovered during its long-time usage. To keep the license up to date, the GPL license includes an optional any later version clause, developers can omit it when licensing their software, for instance the Linux kernel is licensed under GPLv2 without the any later version clause. The GPL was written by Richard Stallman in 1989, for use with programs released as part of the GNU project, the original GPL was based on a unification of similar licenses used for early versions of GNU Emacs, the GNU Debugger and the GNU C Compiler. These licenses contained similar provisions to the modern GPL, but were specific to each program, rendering them incompatible, Stallmans goal was to produce one license that could be used for any project, thus making it possible for many projects to share code. The second version of the license, version 2, was released in 1991, version 3 was developed to attempt to address these concerns and was officially released on 29 June 2007. Version 1 of the GNU GPL, released on 25 February 1989, the first problem was that distributors may publish binary files only—executable, but not readable or modifiable by humans. To prevent this, GPLv1 stated that any vendor distributing binaries must also make the source code available under the same licensing terms. The second problem was that distributors might add restrictions, either to the license, the union of two sets of restrictions would apply to the combined work, thus adding unacceptable restrictions. To prevent this, GPLv1 stated that modified versions, as a whole, had to be distributed under the terms in GPLv1. Therefore, software distributed under the terms of GPLv1 could be combined with software under more permissive terms, according to Richard Stallman, the major change in GPLv2 was the Liberty or Death clause, as he calls it – Section 7. The section says that licensees may distribute a GPL-covered work only if they can all of the licenses obligations. In other words, the obligations of the license may not be severed due to conflicting obligations and this provision is intended to discourage any party from using a patent infringement claim or other litigation to impair users freedom under the license
22.
Software license
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A software license is a legal instrument governing the use or redistribution of software. Under United States copyright law all software is copyright protected, in code as also object code form. The only exception is software in the public domain, most distributed software can be categorized according to its license type. Two common categories for software under copyright law, and therefore with licenses which grant the licensee specific rights, are proprietary software and free, unlicensed software outside the copyright protection is either public domain software or software which is non-distributed, non-licensed and handled as internal business trade secret. Contrary to popular belief, distributed unlicensed software is copyright protected. Examples for this are unauthorized software leaks or software projects which are placed on public software repositories like GitHub without specified license. As voluntarily handing software into the domain is problematic in some international law domains, there are also licenses granting PD-like rights. Therefore, the owner of a copy of software is legally entitled to use that copy of software. Hence, if the end-user of software is the owner of the respective copy, as many proprietary licenses only enumerate the rights that the user already has under 17 U. S. C. §117, and yet proclaim to take away from the user. Proprietary software licenses often proclaim to give software publishers more control over the way their software is used by keeping ownership of each copy of software with the software publisher. The form of the relationship if it is a lease or a purchase, for example UMG v. Augusto or Vernor v. Autodesk. The ownership of goods, like software applications and video games, is challenged by licensed. The Swiss based company UsedSoft innovated the resale of business software and this feature of proprietary software licenses means that certain rights regarding the software are reserved by the software publisher. Therefore, it is typical of EULAs to include terms which define the uses of the software, the most significant effect of this form of licensing is that, if ownership of the software remains with the software publisher, then the end-user must accept the software license. In other words, without acceptance of the license, the end-user may not use the software at all, one example of such a proprietary software license is the license for Microsoft Windows. The most common licensing models are per single user or per user in the appropriate volume discount level, Licensing per concurrent/floating user also occurs, where all users in a network have access to the program, but only a specific number at the same time. Another license model is licensing per dongle which allows the owner of the dongle to use the program on any computer, Licensing per server, CPU or points, regardless the number of users, is common practice as well as site or company licenses
23.
Ethernet
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Ethernet /ˈiːθərnɛt/ is a family of computer networking technologies commonly used in local area networks, metropolitan area networks and wide area networks. It was commercially introduced in 1980 and first standardized in 1983 as IEEE802.3, over time, Ethernet has largely replaced competing wired LAN technologies such as token ring, FDDI and ARCNET. The original 10BASE5 Ethernet uses coaxial cable as a medium, while the newer Ethernet variants use twisted pair. Over the course of its history, Ethernet data transfer rates have increased from the original 2.94 megabits per second to the latest 100 gigabits per second. The Ethernet standards comprise several wiring and signaling variants of the OSI physical layer in use with Ethernet, systems communicating over Ethernet divide a stream of data into shorter pieces called frames. As per the OSI model, Ethernet provides services up to, since its commercial release, Ethernet has retained a good degree of backward compatibility. Features such as the 48-bit MAC address and Ethernet frame format have influenced other networking protocols, the primary alternative for some uses of contemporary LANs is Wi-Fi, a wireless protocol standardized as IEEE802.11. Ethernet was developed at Xerox PARC between 1973 and 1974 and it was inspired by ALOHAnet, which Robert Metcalfe had studied as part of his PhD dissertation. In 1975, Xerox filed a patent application listing Metcalfe, David Boggs, Chuck Thacker, in 1976, after the system was deployed at PARC, Metcalfe and Boggs published a seminal paper. Metcalfe left Xerox in June 1979 to form 3Com and he convinced Digital Equipment Corporation, Intel, and Xerox to work together to promote Ethernet as a standard. The so-called DIX standard, for Digital/Intel/Xerox, specified 10 Mbit/s Ethernet, with 48-bit destination and source addresses and it was published on September 30,1980 as The Ethernet, A Local Area Network. Data Link Layer and Physical Layer Specifications, version 2 was published in November,1982 and defines what has become known as Ethernet II. Formal standardization efforts proceeded at the time and resulted in the publication of IEEE802.3 on June 23,1983. Ethernet initially competed with two largely proprietary systems, Token Ring and Token Bus, in the process, 3Com became a major company. 3Com shipped its first 10 Mbit/s Ethernet 3C100 NIC in March 1981, an Ethernet adapter card for the IBM PC was released in 1982, and, by 1985, 3Com had sold 100,000. Parallel port based Ethernet adapters were produced for a time, with drivers for DOS, by the early 1990s, Ethernet became so prevalent that it was a must-have feature for modern computers, and Ethernet ports began to appear on some PCs and most workstations. This process was sped up with the introduction of 10BASE-T and its relatively small modular connector. Since then, Ethernet technology has evolved to meet new bandwidth, in addition to computers, Ethernet is now used to interconnect appliances and other personal devices
24.
Commodore 64 peripherals
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This article is about the various external peripherals of the Commodore 64 home computer. Due to the compatibility of the Commodore 128, most peripherals will work on that system. Theres some compatibility with the VIC-20 and PET too, in the United States, the 1541 floppy disk drive was widespread. By contrast, in Europe, the C64 was often used with tape drives, which were much cheaper. The Datasette plugged into an edge connector on the Commodore 64s motherboard. Standard blank audio cassettes could be used in this drive, Data tapes could be write-protected in the same way as audio cassettes, by punching out a tab on the cassettes top edge. The Datasettes speed was very slow, loading a large program at normal speed could take up to 30 minutes in extreme cases. Many European software developers wrote their own fast tape-loaders which replaced the internal KERNAL code in the C64, Novaload was perhaps the most popular tape-loader used by British and American software developers. Early versions of Novaload had the ability to play music while a program loaded into memory, other fast-loaders included load screens, displaying computer artwork while the program loaded. More advanced fast-loaders included minigames for the user to play while the program loaded from cassette, One such minigame fastloader was Invade-a-Load. Users also had to contend with interference from magnetic fields, also, not too dissimilar to floppy drive users, the Datasettes read head could become dirty or slip out of alignment. A small screwdriver could be used to align the tape heads, as the Datasette lacked any random read-write access, users had to either wait while the tape ran its length, while the computer printed messages like SEARCHING FOR ALIEN BOXING. LOADING. or else rely on a tape counter number to find the location of programs on cassette. Tape counter speeds varied over different datasette units making recorded counter numbers unreliable on different hardware, an optional streaming tape drive, based upon the QIC-02 format, was available for the Xetec Lt. Kernal hard drive subsystem. They were expensive and few were ever sold, a similar concept to the ZX Microdrive was the extremely fast Phonemark 8500 Quick Data Drive which has 16 -128 kB capacity using a micro-cassette storage unit and used the C2N Datasette. The concept eventually succumbed to floppy drives, the Quick Data Drive connected to the datassette port of the Commodore 64 and could load data at 1.3 kB/s which is 3 times faster than the C1541 floppy drive. It needed a small program code to be loaded in the memory at 0xC000-0xCFFF which collided with other programs. The cost for the drive would have been equivalent to 100 EUR in 2010 and it could also be daisy chained and worked with the VIC-20 computer as well
25.
International Standard Book Number
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The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, however, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay. The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts of a 10-digit ISBN is also done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker
26.
Massachusetts Institute of Technology
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The Massachusetts Institute of Technology is a private research university in Cambridge, Massachusetts, often cited as one of the worlds most prestigious universities. Researchers worked on computers, radar, and inertial guidance during World War II, post-war defense research contributed to the rapid expansion of the faculty and campus under James Killian. The current 168-acre campus opened in 1916 and extends over 1 mile along the bank of the Charles River basin. The Institute is traditionally known for its research and education in the sciences and engineering, and more recently in biology, economics, linguistics. Air Force and 6 Fields Medalists have been affiliated with MIT, the school has a strong entrepreneurial culture, and the aggregated revenues of companies founded by MIT alumni would rank as the eleventh-largest economy in the world. In 1859, a proposal was submitted to the Massachusetts General Court to use newly filled lands in Back Bay, Boston for a Conservatory of Art and Science, but the proposal failed. A charter for the incorporation of the Massachusetts Institute of Technology, Rogers, a professor from the University of Virginia, wanted to establish an institution to address rapid scientific and technological advances. The Rogers Plan reflected the German research university model, emphasizing an independent faculty engaged in research, as well as instruction oriented around seminars, two days after the charter was issued, the first battle of the Civil War broke out. After a long delay through the war years, MITs first classes were held in the Mercantile Building in Boston in 1865, in 1863 under the same act, the Commonwealth of Massachusetts founded the Massachusetts Agricultural College, which developed as the University of Massachusetts Amherst. In 1866, the proceeds from sales went toward new buildings in the Back Bay. MIT was informally called Boston Tech, the institute adopted the European polytechnic university model and emphasized laboratory instruction from an early date. Despite chronic financial problems, the institute saw growth in the last two decades of the 19th century under President Francis Amasa Walker. Programs in electrical, chemical, marine, and sanitary engineering were introduced, new buildings were built, the curriculum drifted to a vocational emphasis, with less focus on theoretical science. The fledgling school still suffered from chronic financial shortages which diverted the attention of the MIT leadership, during these Boston Tech years, MIT faculty and alumni rebuffed Harvard University president Charles W. Eliots repeated attempts to merge MIT with Harvard Colleges Lawrence Scientific School. There would be at least six attempts to absorb MIT into Harvard, in its cramped Back Bay location, MIT could not afford to expand its overcrowded facilities, driving a desperate search for a new campus and funding. Eventually the MIT Corporation approved an agreement to merge with Harvard, over the vehement objections of MIT faculty, students. However, a 1917 decision by the Massachusetts Supreme Judicial Court effectively put an end to the merger scheme, the neoclassical New Technology campus was designed by William W. Bosworth and had been funded largely by anonymous donations from a mysterious Mr. Smith, starting in 1912. In January 1920, the donor was revealed to be the industrialist George Eastman of Rochester, New York, who had invented methods of production and processing
27.
Apache Subversion
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Apache Subversion is a software versioning and revision control system distributed as open source under the Apache License. Software developers use Subversion to maintain current and historical versions of such as source code, web pages. Its goal is to be a mostly compatible successor to the widely used Concurrent Versions System, the open source community has used Subversion widely, for example in projects such as Apache Software Foundation, Free Pascal, FreeBSD, GCC, Mono and SourceForge. CodePlex offers access to Subversion as well as to other types of clients, Subversion was created by CollabNet Inc. in 2000, and is now a top-level Apache project being built and used by a global community of contributors. By 2001, Subversion had advanced sufficiently to host its own source code, in November 2009, Subversion was accepted into Apache Incubator, this marked the beginning of the process to become a standard top-level Apache project. It became a top-level Apache project on February 17,2010, renamed/copied/moved/removed files retain full revision history. The system maintains versioning for directories, renames, and file metadata, users can move and/or copy entire directory-trees very quickly, while retaining full revision history. Native support for files, with space-efficient binary-diff storage. Apache HTTP Server as network server, WebDAV/Delta-V for protocol, there is also an independent server process called svnserve that uses a custom protocol over TCP/IP. Branching is an operation, independent of file size Natively client–server. Client/server protocol sends diffs in both directions, costs proportional to change size, not to data size. Parsable output, including XML log output, open source licensed – Apache License since the 1.7 release, prior versions use a derivative of the Apache Software License 1.1. Language bindings for C#, PHP, Python, Perl, Ruby, full MIME support – users can view or change the MIME type of each file, with the software knowing which MIME types can have their differences from previous versions shown. Merge tracking – Merges between branches will be tracked, this allows automatic merging between branches without telling Subversion what does and does not need to be merged, changelists to organize commits into commit groups. Subversion offers two types of repository storage, the original development of Subversion used the Berkeley DB package. Subversion has some limitations with Berkeley DB usage when a program that accesses the database crashes or terminates forcibly, no data loss or corruption occurs, but the repository remains offline while Berkeley DB replays the journal and cleans up any outstanding locks. The safest way to use Subversion with a Berkeley DB repository involves a single server-process running as one user, in 2004, a new storage subsystem was developed and named FSFS. It works faster than the Berkeley DB backend on directories with a number of files and takes less disk space
