The COSMAC (Complementary Symmetry Monolithic Array Computer) is an 8-bit microprocessor family introduced by RCA . It is historically notable as the first CMOS microprocessor. The first production model was the two-chip CDP1801R and CDP1801U , which were later combined into the single-chip CDP1802 . The 1802 represented the majority of COSMAC production, and today the entire line is known simply as the RCA 1802 .
151-519: The processor design traces its history to an experimental home computer designed by Joseph Weisbecker in the early 1970s, built at his home using TTL components. RCA began development of the CMOS version of the processor design in 1973, sampling it in 1974 with plans to move to a single-chip implementation immediately. Jerry Herzog led the design of the single-chip version, which sampled in 1975 and entered production in 1976. In contrast to most designs of
302-468: A character generator and the ability to load and save programs on cassette tapes . Weisbecker's daughter, Joyce Weisbecker , was immediately drawn to the system and began writing programs for it. This included several games, which were ported to later machines based on the COSMAC. When RCA entered the game console business in the later 1970s, these games were burned to ROM cartridge form, and Joyce became
453-488: A disk drive (the Commodore 1541 was the only fully-compatible model) or Datasette before they could make use of it as anything but a game machine or TV Typewriter . In the early part of the 1980s, the dominant microprocessors used in home computers were the 8-bit MOS Technology 6502 (Apple, Commodore, Atari, BBC Micro ) and Zilog Z80 ( TRS-80 , ZX81 , ZX Spectrum , Commodore 128 , Amstrad CPC ). One exception
604-488: A " poison pill " in the form of a major share price hike to dissuade the hostile bid, the result of which caused Burroughs to borrow much more funding than was anticipated to complete the bid. Certain internal divisions of Sperry were sold off after the merger, such as Sperry New Holland (1986, to Ford Motor Company , who in 1991 sold the Ford-New Holland line to Fiat ) and Sperry Marine (to Tenneco , in 1987, and
755-510: A "prototype" being delivered in 1972, but this is likely referring to the original TTL implementation. It goes on to note that an effort to reduce the processor to a two-chip implementation with deliveries in COS/MOS in 1974. It is here that the processor is first referred to as COSMAC, for COmplementary-Symmetry-Monolithic-Array Computer. It goes on to state that another lab will be producing the system in an 8-chip silicon-on-sapphire format, although
906-427: A 6502 processor and ran DOS from internal ROM. While this gave Commodore systems some advanced capabilities – a utility program could sideload a disk copy routine onto the drive and return control to the user while the drive copied the disk on its own – it also made Commodore drives more expensive and difficult to clone. Many home computers had a cartridge interface which accepted ROM-based software. This
1057-530: A built-in keyboard to support its C7420 Home Computer Module. Among third-generation consoles , Nintendo 's Family Computer offered Family BASIC (sold only in Japan), which included a keyboard that could be connected to an external tape recorder to load and store programs. Books of type-in program listings like BASIC Computer Games were available, dedicated for the BASICs of most models of computer, with titles along
1208-597: A common category of utility software in this pre- DMCA era. In another defining characteristic of the home computer, instead of a command line , the BASIC interpreter served double duty as a user interface. Coupled to a character-based screen or line editor , BASIC's file management commands could be entered in direct mode . In contrast to modern computers, home computers most often had their operating system (OS) stored in ROM chips. This made startup times very fast (no more than
1359-566: A dedicated phone line operated bulletin boards of their own. This capability anticipated the internet by nearly 20 years. Some game consoles offered "programming packs" consisting of a version of BASIC in a ROM cartridge . Atari's BASIC Programming for the Atari 2600 was one of these. For the ColecoVision console, Coleco even announced an expansion module which would convert it into a full-fledged computer system. The Magnavox Odyssey² console had
1510-637: A few seconds), but made OS upgrades difficult or impossible without buying a new unit. Usually, only the most severe bugs were fixed by issuing new ROMs to replace the old ones at the user's cost. In addition, the small size and limited scope of home computer "operating systems" (really little more than what today would be called a kernel) left little room for bugs to hide. Although modern operating systems include extensive programming libraries to ease development and promote standardization, home computer operating systems provided little support to application programs. Professionally-written software often switched out
1661-465: A first for a stand-alone computer, costing far less than dedicated motion-video processing equipment costing many thousands of dollars. Stereo sound became standard for the first time; the Atari ST gained popularity as an affordable alternative for MIDI equipment for the production of music. Clock rates on the 68000-based systems were approximately 8 MHz with RAM capacities of 256 kB (for
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#17328562180071812-622: A floppy disk drive. It was available for the TRS-80 and some others. A closely-related technology was the ZX Microdrive , developed by Sinclair Research in the UK, for their ZX Spectrum and QL home computers. Eventually, mass production of 5.25" drives resulted in lower prices, and after about 1984, they pushed cassette drives out of the US home computer market. 5.25" floppy disk drives would remain standard until
1963-432: A game now and then, learn more about computers, and help educate their children". By 1986, industry experts predicted an "MS-DOS Christmas", and the magazine stated that clones threatened Commodore, Atari, and Apple's domination of the home-computer market. The declining cost of IBM compatibles on the one hand, and the greatly-increased graphics, sound, and storage abilities of fourth generation video game consoles such as
2114-568: A go-between, using multiple instructions to perform the operations. The processor has five special I/O lines. There is a single Q output that can be set with the SEQ instruction and reset with the REQ instruction. There are four external, single-bit flag inputs, EF1, EF2, EF3, and EF4, and there are eight dedicated branch instructions to conditionally branch based on the state of those input lines. There are seven Input and seven Output port instructions that utilize
2265-704: A great deal of software support from the traditional Japanese publishers of game software. Microsoft developed the MSX-DOS operating system, a version of their popular MS-DOS adapted to the architecture of these machines, that was also able to run CP/M software directly After the first wave of game consoles and computers landed in American homes, the United States Federal Communications Commission (FCC) began receiving complaints of electromagnetic interference to television reception. By 1979
2416-469: A high performer, the Equity was a reliable and compatible design for half the price of a similarly-configured IBM PC. Epson often promoted sales by bundling one of their printers with it at cost. The Equity I sold well enough to warrant the furtherance of the Equity line with the follow-on Equity II and Equity III. In 1986, UK home computer maker Amstrad began producing their PC1512 PC-compatible for sale in
2567-418: A home automation appliance would require the computer to be kept powered on at all times and dedicated to this task. Personal finance and database use required tedious data entry . By contrast, advertisements in the specialty computer press often simply listed specifications, assuming a knowledgeable user who already had applications in mind. If no packaged software was available for a particular application,
2718-415: A home television. Indeed, the use of a television set as a display almost defines the pre-PC home computer. Although dedicated composite or " green screen " computer displays were available for this market segment and offered a sharper display, a monitor was often a later purchase made only after users had bought a floppy disk drive, printer, modem, and the other pieces of a full system. The reason for this
2869-652: A host of other manufacturers. For many of these businesses, the development of the microcomputer made computing and business software affordable where they had not been before. Introduced in August 1981, the IBM Personal Computer would eventually supplant CP/M as the standard platform used in business. This was largely due to the IBM name and the system's 16 bit open architecture , which expanded maximum memory tenfold, and also encouraged production of third-party clones . In
3020-469: A keyboard integrated into the same case as the motherboard , or, more frequently, a mainboard . While the expandable home computers appeared from the very start (the Apple II offered as many as seven expansion slots) as the whole segment was generally aimed downmarket , few offers were priced or positioned high enough to allow for such expandability. Some systems have only one expansion port, often realized in
3171-511: A major military contractor. From 1967 to 1973 the corporation was involved in an acrimonious antitrust lawsuit with Honeywell , Inc. (see Honeywell v. Sperry Rand ). In 1961, Sperry Rand was ranked 34th on the Fortune 500 list of largest companies in the United States. In 1977, Sperry Rand purchased Varian Data Machines so as to enter the minicomputer market. Varian would be renamed as
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#17328562180073322-401: A number of industry-leading developments taking place there. Some of the skepticism displayed by management may have had to do with the company's recent sale of their mainframe computer business to Sperry Rand with a huge writedown . Eventually, the company became interested in the system and began adapting it to their newly introduced COS/MOS fabrication system. A 1973 lab report refers to
3473-675: A palette of 512. MSX was a standard for a home computing architecture that was intended and hoped to become a universal platform for home computing. It was conceived, engineered and marketed by Microsoft Japan with ASCII Corporation . Computers conforming to the MSX standard were produced by most all major Japanese electronics manufacturers, as well as two Korean ones and several others in Europe and South America. Some 5 million units are known to have been sold in Japan alone. They sold in smaller numbers throughout
3624-433: A place to plug in cartridge-based games. Usually, the manufacturer would sell peripheral devices designed to be compatible with their computers as extra-cost accessories. Peripherals and software 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 dedicated monitor, the home computer would often connect through an RF modulator to
3775-491: A program that allowed businesses to sell computers tax-free to its employees, often accompanied by home training programs. Naturally, these businesses chose to equip their employees with the same systems they themselves were using. Today, a computer bought for home use anywhere will be very similar to those used in offices; made by the same manufacturers, with compatible peripherals, operating systems, and application software. Many home computers were superficially similar. Most had
3926-496: A prolonged hostile takeover bid engineered by Burroughs Corporation , which merged the combined operation under the new name Unisys . Some of Sperry's former divisions became part of Honeywell , Lockheed Martin , Raytheon Technologies , and Northrop Grumman . The company is best known as the developer of the artificial horizon and a wide variety of other gyroscope -based aviation instruments like autopilots , bombsights , analog ballistics computers and gyro gunsights . In
4077-503: A reboot to use the system for something else. In an enduring reflection of their early cassette-oriented nature, most home computers loaded their disk operating system (DOS) separately from the main OS. The DOS was only used for disk and file-related commands and was not required to perform other computing functions. One exception was Commodore DOS , which was not loaded into the computer's main memory at all – Commodore disk drives contained
4228-587: A stack. Although any of the available registers can be used for this technique, per programmer's preference, many use the routine supplied by RCA in the CDP1802 User Manual, where the suggested register usage is R2 = Stack Pointer, R3 = General Program Counter (PC), R4 = Call, R5 = Return, R6 = Passed Arguments Pointer (non-destructive). Even though these supportive routines are small, there is an execution speed overhead using them. (as opposed to what would be incurred if actual CALL and RET instructions were part of
4379-559: A standard of its own, known as Tandy Graphics Adapter or TGA. Later, Tandy produced Tandy 1000 variants in form factors and price-points even more suited to the home computer market, comprised particularly by the Tandy 1000 EX and HX models (later supplanted by the 1000 RL ), which came in cases resembling the original Apple IIs (CPU, keyboard, expansion slots, and power supply in a slimline cabinet) but also included floppy disk drives. The proprietary Deskmate productivity suite came bundled with
4530-502: A subroutine returns, it jumps to the location immediately preceding its entry point so that after the SEP "return" instruction returns control to the caller, the register will be pointing to the right value for next usage. (the processor always increments the PC after reference and usage (retrieving the next instruction to execute), so this technique works as noted) An interesting variation of this scheme
4681-485: A turbo NEC V40 CPU (up-rated 8088) which was rather slow for its time, but the video monitor did feature 400-pixel vertical resolution. This unique computer failed for the same reasons as did IBM's PCjr: poor performance and expandability, and a price too high for the home market. Another company that offered low-cost PCs for home use was Leading Edge , with their Model M and Model D computers. These were configured like full-featured business PCs, yet still could compete in
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4832-605: A volume control was implemented). Traditionally, the EF4 line is attached to the INPUT momentary pushbutton on the COSMAC Elf. Other systems might use one of the other lines. There are some other special use registers and flags, some internal, and some usable programmatically: 4-bit N, P, X, and I; 8-bit T; and 1-bit IE. On the Internet, there is many versions of a Table of the 1802 Instructions, here
4983-524: Is currently part of Northrop Grumman ). Also sold—to Honeywell —was Sperry Aerospace Group , while Sperry Defense Products Group was sold to Loral ; those two units whose functions were originally at the heart of the venerable Sperry Gyroscope division. This group is now part of Lockheed Martin . Sperry in Britain started with a factory in Pimlico , London, in 1913, manufacturing gyroscopic compasses for
5134-554: Is done on a piece of paper. Of course sometimes the Data is moved to and from the Ram Memory section, and different Branches of the Program are done, as needed, in the flow of time. There are three types of unconditional and conditional branching in the 1802, Short and Long, and Skips. Short branches are 2-byte instructions, and use 256-byte range, single byte address, page absolute addressing in
5285-567: Is one link : https://www.atarimagazines.com/computeii/issue3/page52.php There is a number of Tables in the File area for logged in members of the 1802 online club for forum at https://groups.io/g/cosmacelf/files . Each Instruction is a single Byte, of 8 Bits. The 4 Bits to the Left, sometimes called High Order Hex Digit, are to do with the actual nature of the Instruction, and those 4 Bits are involved with
5436-511: Is the 8-bit 'D' register (Data register). The single bit carry flag is DF (Data Flag). Most operations use the D register, including arithmetic and logic functions, and memory referencing load and store instructions. Most 16-bit operations have to work on the lower byte and then the upper byte, via D, using the DF as carry and borrow as needed. An important feature of the 1802 is a set of sixteen registers of 16 bits each, used primarily for addressing. Using
5587-528: Is to have two or more subroutines in a ring so that they are called in round robin order. On early hobbyist computers, tricks and techniques like this were commonly used in the horizontal refresh interrupt to reprogram the scan line address to repeat each scan line four times for the video controller. One well-known and often-used routine is known as SCRT (Standard CALL and RETURN Technique), which allows general purpose subroutine Call and Return, including passing of parameters "in line", and nested subroutines using
5738-600: The Atari 1040ST (not the 520ST), Amiga , and Tandy 1000 , did house floppy drive(s) internally. At any rate, to expand any computer with additional floppy drives, external units would have to be plugged in. Toward the end of the home computer era, drives for a number of home computer models appeared offering disk-format compatibility with the IBM PC. The disk drives sold with the Commodore 128, Amiga, and Atari ST were all able to read and write PC disks, which themselves were undergoing
5889-545: The British Aerospace brand. State of the art, high technology MEMS gyroscopes (together with other avionics equipment) are still made on the site today, although the company is now owned by United Technologies Corporation and is part of UTC Aerospace Systems . The name Sperry lives on in the company Sperry Marine , headquartered in New Malden , England. This company, formed in 1997, from three well-known brand names in
6040-461: The Commodore PET , and the original Apple II in 1977, almost every manufacturer of consumer electronics rushed to introduce a home computer. Large numbers of new machines of all types began to appear during the late 1970s and early 1980s. Mattel , Coleco , Texas Instruments , and Timex , none of which had any prior connection to the computer industry, all had short-lived home computer lines in
6191-565: The Galileo probe to Jupiter in 1989, and it remains in use in similar roles to this day. A number of early microcomputers were based on the 1802, including the COSMAC ELF (1976), Netronics ELF II , Quest SuperELF , COSMAC VIP , Comx-35 , Finnish Telmac 1800 , Telmac TMC-600 and Oscom Nano , Yugoslav Pecom 32 and 64 , and the CyberVision 2001 systems sold through Montgomery Ward in
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6342-556: The Galileo spacecraft , Magellan , the Plasma Wave Analyzer instrument on ESA's Ulysses spacecraft, various Earth-orbiting satellites and satellites carrying amateur radio. The 1802 has also been verified from NASA source documentation to have been used in the Hubble Space Telescope . A number of British military items from the 1980s and 1990s used the 1802, amongst them: The first high-level language available for
6493-538: The Membership Card microcomputer kit that fits in an Altoids tin and the Spare Time Gizmos Elf 2000 (Elf 2K), among others. See § Emulators and simulators for other systems. The 1802 was also used in scientific instruments and commercial products. Post-1980 Chrysler and associated model vehicles use the 1802 in their second-generation Electronic Lean-Burn System, with electronic spark control, one of
6644-460: The Motorola 68008 with its external 8-bit bus). Graphics resolutions approximately doubled to give roughly NTSC -class resolution, and color palettes increased from dozens to hundreds or thousands of colors available. The Amiga was built with a custom chipset with dedicated graphics and sound coprocessors for high-performance video and audio. The Amiga found use as a workstation for desktop video ,
6795-540: The Nintendo Entertainment System , but no longer sold home computers. Toward the end of the 1980s, clones also became popular with non-corporate customers. Inexpensive, highly-compatible clones succeeded where the PCjr had failed. Replacing the hobbyists who had made up the majority of the home computer market were, as Compute! described them, "people who want to take work home from the office now and then, play
6946-480: The PCjr as a PC/DOS-compatible machine aimed squarely at the home user. It proved a spectacular failure because IBM deliberately limited its capabilities and expansion possibilities in order to avoid cannibalizing sales of the profitable PC. IBM management believed that if they made the PCjr too powerful, too many buyers would prefer it over the bigger, more expensive PC. Poor reviews in the computer press and poor sales doomed
7097-610: The Royal Navy . It became the Sperry Gyroscope Co Ltd in 1915. In 1923, Lawrence Sperry was killed in an air crash near Rye, Sussex . The company subsequently expanded to the Golden Mile , Brentford in 1931, Stonehouse , Gloucestershire in 1938, and Bracknell in 1957. By 1963, these sites employed some 3,500 people. The Brentford site closed in 1967, with the expansion of Bracknell. Stonehouse closed around 1969. By 1969,
7248-543: The Sega Genesis and Super Nintendo Entertainment System on the other, combined to cause the market segment for home computers to vanish by the early 1990s in the US. In Europe, the home computer remained a distinct presence for a few years more, with the low-end models of the 16-bit Amiga and Atari ST families being the dominant players, but by the mid-1990s, even the European market had dwindled. The Dutch government even ran
7399-473: The Sinclair ZX80 , which were both home and home-built computers since the purchaser could assemble the unit from a kit. Advertisements in the popular press for early home computers were rife with possibilities for their practical use in the home, from cataloging recipes to personal finance to home automation , but these were seldom realized in practice. For example, using a typical 1980s home computer as
7550-474: The integrated circuits , other individual electronic components, wires and connectors, and then hand- solder all the connections. While two early home computers ( Sinclair ZX80 and Acorn Atom ) could be bought either in kit form or assembled, most home computers were only sold pre-assembled. They were enclosed in plastic or metal cases similar in appearance to typewriter or hi-fi equipment enclosures, which were more familiar and attractive to consumers than
7701-422: The 16 registers; however, the called subroutine must know (hard coded) what the calling PC register is to perform the "return" instruction. The SEP instruction is used to call a subroutine pointed to by one of the 16-bit registers and another SEP to return to the caller (SEP stands for Set Program Counter , and selects which one of the 16 registers is to be used as the program counter from that point onward). Before
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#17328562180077852-622: The 1802 are the CDP1804, CDP1805, and CDP1806, which have an extended instruction set, other enhanced features (like on-chip RAM and ROM, and built-in timer), with some versions running at faster clock speeds, though not a significant speed difference. Some features are also lost, like the DMA auto-boot loader functionality. There are also some minor pin function changes, but the line continues to be produced in its original 40-pin dual in-line package (DIP) format. Joseph Weisbecker had long been fascinated with
8003-599: The 1802 was Forth , provided by Forth, Inc. and it was known as MicroFORTH, in 1976 (see Forth Inc's archive). Other available programming languages, both interpreters and compilers, are CHIP-8 (It was also invented by Joseph Weisbecker ) (and variants), 8th (a version of Forth created by Lee Hart), Tom Pittman's Tiny BASIC , C, various Assemblers and cross-assemblers, and others. Other specialty languages were used by federal agencies such as NASA and its installations, including Johnson Space Center, AMES, Goddard, Langley, Marshall, and Jet Propulsion Laboratory (JPL), which included
8154-483: The 1802's initial release, up until the collapse of RCA itself. These were mainly aimed at industrial applications and systems development, and were highly configurable. The COSMAC was unique among early 8-bit processors in that it had been explicitly designed for microcomputer use; other designs of the era were invariably aimed at the embedded processor space, and those that had been designed for computer use were generally more complex systems, and often 16-bit. Although
8305-496: The 1802, developed jointly by RCA and Sandia National Laboratories , was built on bulk silicon using CL (Closed COS/MOS Logic) technology. Along with its extreme low-power abilities, this makes the chip well-suited in space and military applications. (Also, at the time the 1802 was introduced, very few, if any, other radiation-hardened microprocessors were available in the market). The 1802 was used in many spacecraft and space science programs, experiments, projects and modules such as
8456-537: The Atari and Commodore 8-bit machines, coprocessors were added to speed processing of graphics and audio data. For these computers, clock rate was considered a technical detail of interest only to users needing accurate timing for their own programs. To economize on component cost, often the same crystal used to produce color television-compatible signals was also divided down and used for the processor clock. This meant processors rarely operated at their full rated speed, and had
8607-524: The BASIC interpreter was also used as the user interface , and given tasks such as loading, saving, managing, and running files. One exception was the Jupiter Ace , which had a Forth interpreter instead of BASIC. A built-in programming language was seen as a requirement for any computer of the era, and was the main feature setting home computers apart from video game consoles . Still, home computers competed in
8758-554: The COSMAC had been designed for computer use, RCA's slow market entry and undersupported attempts in this market ultimately failed and other processors like the MOS 6502 and Zilog Z80 would come to dominate this market. Ironically, COSMAC would ultimately find great success in the embedded market, because its CMOS design allowed it to work at lower power. By the late 1970s it was widely used in many industrial settings, and especially aerospace. Multiple 1802s were used as auxiliary IO processors in
8909-468: The FCC demanded that home computer makers submit samples for radio frequency interference testing. It was found that "first generation" home computers emitted too much radio frequency noise for household use. The Atari 400 and 800 were designed with heavy RF shielding to meet the new requirements. Between 1980 and 1982 regulations governing RF emittance from home computers were phased in. Some companies appealed to
9060-400: The FCC to waive the requirements for home computers, while others (with compliant designs) objected to the waiver. Eventually techniques to suppress interference became standardized. Sperry Rand Sperry Corporation was a major American equipment and electronics company whose existence spanned more than seven decades of the 20th century. Sperry ceased to exist in 1986 following
9211-565: The HAL/S cross-compiler, STOIC , a Forth-like language, and others. Interpreter for Process Structures (IPS), a programming language and development environment, was specifically written and used for real-time control of AMSAT satellites. The 1802 chip and computers using the microprocessor have been emulated and simulated in hardware and/or software by hobbyists. There are three designs in VHDL for an FPGA . A bus-accurate, full speed COSMAC Elf clone
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#17328562180079362-571: The I Register. The 4 Bits to the Right, sometimes called Low Order Hex Digit, are to do with the working Register, where Data is taken from, or put into it, and those 4 Bits are involved with the N Register. When a Program is being done, the various stages of the work and the Processes, are stored temporarily in the Register pointed to by the N Register, like what happens, when long Multiplication, or long Division,
9513-521: The Macintosh itself was too expensive for most households. The Amiga in particular had true multitasking capability, and unlike all other low-cost computers of the era, could run multiple applications in their own windows. The second generation of MSX computers (MSX2) achieved the performance of high-performance computers using a high-speed video processor ( Yamaha V9938 ) capable of handling resolutions of 512 × 424 pixels, and 256 simultaneous colors from
9664-462: The PCjr. Tandy Corporation capitalized on IBM's blunder with its PCjr-compatible Tandy 1000 in November. Like the PCjr, it was pitched as a home, education, and small-business computer, featuring joystick ports, better sound and graphics (same as the PCjr but with enhancements), combined with near-PC/DOS compatibility (unlike Tandy's earlier Tandy 2000 ). The improved Tandy 1000 video hardware became
9815-513: The ROM-based OS anyway to free the address space it occupied and maximize RAM capacity. This gave the program full control of the hardware and allowed the programmer to optimize performance for a specific task. Games would often turn off unused I/O ports, as well as the interrupts that served them. As multitasking was never common on home computers, this practice went largely unnoticed by users. Most software even lacked an exit command, requiring
9966-444: The RX register and D accumulator. The EF and Q lines were typically used for multiple interfaces on 1802-based hobbyist computers because of the lines' favorable and easy handling. It was typical for the Q line to drive a status LED , a cassette interface, an RS-232 interface, and the speaker. This meant that the user could actually hear RS-232 and cassette data being transmitted (unless
10117-550: The Remington Rand acquisition, Sperry Gyroscope decided to open a facility that would almost exclusively produce its marine instruments. After considerable searching and evaluation, a plant was built in Charlottesville, Virginia , and in 1956, Sperry Piedmont Division began producing marine navigation products. It was later renamed Sperry Marine . In the 1970s, Sperry Corporation was a traditional conglomerate headquartered in
10268-453: The SEP instruction, you can select any of the 16 registers to be the program counter ; using the SEX instruction, you can select any of the 16-bit registers to be the index register . Register R0 has the special use of holding the memory address for the built-in DMA controller. Register R1 has the special use of being the program counter for the interrupt handler. There are instructions that allow
10419-625: The Sperry Gyroscope division of Sperry Rand Corporation employed around 2,500. The site of the Bracknell factory and development center (sold to British Aerospace in 1982) is commemorated by a 4.5-meter aluminum sculpture by Philip Bentham , Sperry's New Symbolic Gyroscope (1967). In 1989, the Bracknell site was downsized and work was moved to the Sperry manufacturing site in Plymouth by then under
10570-605: The Sperry Rand Building at 1290 Avenue of Americas in Manhattan, selling typewriters (Sperry Remington); office equipment, electronic digital computers for business and the military (Sperry Univac); construction and farm equipment (Sperry New Holland); avionics, such as gyroscopes, radars, air route traffic control equipment (Sperry Vickers/Sperry Flight Systems); and consumer products such as electric razors (Sperry Remington). In addition, Sperry Systems Management (headquartered in
10721-545: The Sperry UNIVAC Minicomputer Operation, operating as part of the Sperry UNIVAC division. In 1978, Sperry Rand decided to concentrate on its computing interests, and sold a number of divisions including Remington Rand Systems, Remington Rand Machines, Ford Instrument Company and Sperry Vickers . The company dropped "Rand" from its title and reverted to Sperry Corporation . At about the same time as
10872-680: The Studio II was announced only in January 1977, a couple of months after the Fairchild Channel F became the first cartridge-based machine on the market. Both would soon be eclipsed and largely forgotten due to the release of the Atari 2600 later that year. RCA canceled the Studio II in February 1978. RCA also released a series of modular computer systems, based on the RCA Microboard form factor from
11023-549: The Tandy 1000s. Deskmate was suited to use by computer novices with its point-and-click (though not graphical) user interface. From the launch of the Tandy 1000 series, their manufacture were price-competitive because of Tandy's use of high-density ASIC chip technology, which allowed their engineers to integrate many hardware features into the motherboard (obviating the need for circuit cards in expansion slots as with other brands of PC). Tandy never transferred its manufacturing operation to Asia; all Tandy desktop computers were built in
11174-644: The UK. Later they would market the machine in the US as the PC6400. In June 1987, an improved model was produced as the PC1640. These machines had fast 8086 CPUs, enhanced CGA graphics, and were feature-laden for their modest prices. They had joystick adapters built into their keyboards and shipped with a licensed version of the Digital Research 's GEM , a GUI for the MS-DOS operating system. They became marginal successes in
11325-643: The USA (this was not true of the laptop and pocket computers, nor peripherals). In 1985, the Epson corporation, a popular and respected producer of inexpensive dot-matrix printers and business computers (the QX-10 and QX-16 ), introduced its low-cost Epson Equity PC. Its designers took minor shortcuts, such as few expansion slots and a lack of a socket for an 8087 math chip, but Epson did bundle some utility programs that offered decent turnkey functionality for novice users. While not
11476-431: The ability to run industry-standard MS-DOS software on affordable, user-friendly PCs was anticipated as a source of new sales. Furthermore, many in the industry felt that MS-DOS would eventually (inevitably, it seemed) come to dominate the computer business entirely, and some manufacturers felt the need to offer individual customers PC-style products suitable for the home market. In early 1984, market colossus IBM produced
11627-435: The address into a spare register; followed by an instruction to select that register as the index register; followed, finally, by the intended operation on the data variable that is pointed to by that address. Home computer Home computers were a class of microcomputers that entered the market in 1977 and became common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for
11778-425: The author to obtain the programs on disk or cassette for a few dollars. Before the Internet, and before most computer owners had a modem , books were a popular and low-cost means of software distribution—one that had the advantage of incorporating its own documentation. These books also served a role in familiarizing new computer owners with the concepts of programming; some titles added suggested modifications to
11929-472: The base Amiga 1000 ) up to 1024 kB ( 1 MB , a milestone, first seen on the Atari 1040ST). These systems used 3.5" floppy disks from the beginning, but 5.25" drives were made available to facilitate data exchange with IBM PC compatibles. The Amiga and ST both had GUIs with windowing technology. These were inspired by the Macintosh , but at a list price of US$ 2,495 (equivalent to $ 7,100 in 2023),
12080-559: The company diversified into aircraft components including bomb sights and fire control systems . In their early decades, Sperry Gyroscope and related companies were concentrated on Long Island , New York, especially in Nassau County . Over the years, it diversified to other locations. In 1918, Lawrence Sperry split from his father to compete over aero-instruments with the Lawrence Sperry Aircraft Company , including
12231-530: The company's first digital computer, SPEEDAC , in 1953. During the 1950s, a large part of Sperry Gyroscope moved to Phoenix , Arizona and soon became the Sperry Flight Systems Company. This was to preserve parts of this defense company in the event of a nuclear war . The Gyroscope division remained headquartered in New York—in its massive Lake Success , Long Island, plant (which also served as
12382-417: The constant, each one followed by a Put instruction to the register, PHI and PLO). The two addressing modes Indirect register , and Indirect register with auto-increment are then fairly efficient, to perform 8-bit operations on the data in the accumulator. There are no other addressing modes, though. Thus, the direct addressing mode needs to be emulated using the four instructions mentioned earlier to load
12533-502: The contents of one register to another involves four instructions (one Get and one Put on the HI byte of the register, and a similar pair for the LO byte: GHI R1; PHI R2; GLO R1; PLO R2). Similarly, loading a new constant into a register (such as a new address for a subroutine jump, or the address of a data variable) also involves four instructions (two load immediate, LDI, instructions, one for each half of
12684-445: The date is simply "soon after" the CMOS versions, and that plans for a single-chip version were already being planned. Although RCA began the development of the COSMAC in the early 1970s, it was some time before they introduced their own products based on it. In 1975, a prototype of an arcade game machine with swappable ROMs was experimented with for the coin-op business, but was ultimately abandoned. Meanwhile, Weisbecker had adapted
12835-471: The default PC floppy was double-sided, with about twice the storage capacity of floppy disks used by 8-bit home computers. PC drives tended to cost less because they were most often built-in, requiring no external case, controller, or power supply. The faster clock rates and wider buses available to later Intel CPUs compensated somewhat for the custom graphics and sound chips of the Commodores and Ataris. In time,
12986-478: The early 1980s. Some home computers were more successful. The BBC Micro , Sinclair ZX Spectrum , Atari 8-bit computers , and Commodore 64 sold many units over several years and attracted third-party software development. Almost universally, home computers had a BASIC interpreter combined with a line editor in permanent read-only memory , which one could use to type in BASIC programs and execute them immediately, or save them to tape or disk. In direct mode ,
13137-487: The end of the 8-bit era. Though external 3.5" drives were made available for home computer systems toward the latter part of the 1980s, almost all software sold for 8-bit home computers remained on 5.25" disks. 3.5" drives were used for data storage, with the exception of the Japanese MSX standard, on which 5.25" floppies were never popular. Standardization of disk formats was not common; sometimes, even different models from
13288-543: The era, which were fabricated using the NMOS process, the COSMAC was implemented in CMOS form and used static logic . This allowed it to run at lower power settings and even be stopped completely; in addition it would run cooler and not generate as much heat as NMOS chips. RCA also produced radiation hardened versions, which found use in the aerospace field. These remain in production as of 2022, and as of 2008 continued to be produced by Renesas (formerly Intersil ). Successors to
13439-416: The family TV set, which served as both video display and sound system. The rise of the home computer also led to a fundamental shift during the early 1980s in where and how computers were purchased. Traditionally, microcomputers were obtained by mail order or were purchased in person at general electronics retailers like RadioShack . Silicon Valley , in the vanguard of the personal computer revolution,
13590-465: The few business users. Various copy protection schemes were developed for floppy disks; most were broken in short order. Many users would only tolerate copy protection for games, as wear and tear on disks was a significant issue in an entirely floppy-based system. The ability to make a "working backup" disk of vital application software was seen as important. Copy programs that advertised their ability to copy or even remove common protection schemes were
13741-465: The first known female commercial videogame developer. Weisbecker demonstrated the machine to RCA management throughout this period, but there was little interest at first. This was shortly after David Sarnoff had retired and handed the CEO role to his son, Robert Sarnoff . Robert was more interested in building the media side of the company while dating recording stars, ignoring RCA Laboratories in spite of
13892-496: The first on-board auto computer-based control systems. The 1802 was used in the manufacture of many pinball machines and video arcade games in Spain. A high-speed version of the 1802 was fabricated in Silicon on Sapphire (SOS) semiconductor process technology, which gives it a degree of resistance to radiation and electrostatic discharge (ESD). A different radiation-hardened version of
14043-756: The first time, were intended for the use of a single, non-technical user. These computers were a distinct market segment that typically cost much less than business, scientific, or engineering-oriented computers of the time, such as those running CP/M or the IBM PC , and were generally less powerful in terms of memory and expandability. However, a home computer often had better graphics and sound than contemporary business computers. Their most common uses were word processing , playing video games , and programming . Home computers were usually sold already manufactured in stylish metal or plastic enclosures. However, some home computers also came as commercial electronic kits , like
14194-472: The form of cumbersome "sidecar" systems, such as on the TI-99/4 , or required finicky and unwieldy ribbon cables to connect the expansion modules. Sometimes they were equipped with a cheap membrane or chiclet keyboard in the early days, although full-travel keyboards quickly became universal due to overwhelming consumer preference. Most systems could use an RF modulator to display 20–40 column text output on
14345-606: The game console showed a blank screen or continued playing the same repetitive game. Another capability home computers had that game consoles of the time lacked was the ability to access remote services over telephone lines by adding a serial port interface, a modem , and communication software . Though it could be costly, it permitted the computer user to access services like Compuserve , and private or corporate bulletin board systems and viewdata services to post or read messages, or to download or upload software. Some enthusiasts with computers equipped with large storage capacity and
14496-463: The general 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 (nicknamed " blinkenlights ") to control and indicate internal system status, and were often sold in kit form to hobbyists. These kits would contain an empty printed circuit board which the buyer would fill with
14647-414: The growing popularity of home PCs spurred many software publishers to offer gaming and children's software titles. Many decision-makers in the computer industry believed there could be a viable market for office workers who used PC/DOS computers at their jobs and would appreciate an ability to bring diskettes of data home on weeknights and weekends to continue work after-hours on their "home" computers. So,
14798-537: The home computer era is that the once-common endeavor of writing one's own software programs has almost vanished from home computer use. As early as 1965, some experimental projects, such as Jim Sutherland's ECHO IV , explored the possible utility of a computer in the home. In 1969, the Honeywell Kitchen Computer was marketed as a luxury gift item, and would have inaugurated the era of home computing, but none were sold. Computers became affordable for
14949-443: The home computer user could program one—provided they had invested the requisite hours to learn computer programming , as well as the idiosyncrasies of their system. Since most systems arrived with the BASIC programming language included on the system ROM , it was easy for users to get started creating their own simple applications. Many users found programming to be a fun and rewarding experience, and an excellent introduction to
15100-447: The home market on price because Leading Edge had access to low-cost hardware from their Asian manufacturing partners Mitsubishi with the Model M and Daewoo with the Model D. The LEWP was bundled with the Model D. It was favorably reviewed by the computer press and sold very well. By the mid '80s, the market for inexpensive PCs for use in the home market was expanding at such a rate that
15251-478: The home market. In 1987, longtime small computer maker Zenith introduced a low-cost PC they called the EaZy PC . This was positioned as an "appliance" computer much like the original Apple Macintosh: turnkey startup, built-in monochrome video monitor, and lacking expansion slots, requiring proprietary add-ons available only from Zenith, but instead with the traditional MS-DOS Command-line interface . The EaZy PC used
15402-484: The home". In 1990, the company reportedly refused to support joysticks on its low-cost Macintosh LC and IIsi computers to prevent customers from considering them as "game machines". Although the Apple II and Atari computers are functionally similar, Atari's home-oriented marketing resulted in a game-heavy library with much less business software. By the late 1980s, many mass merchants sold video game consoles like
15553-459: The image of, as Compute! wrote, "a low-powered, low-end machine primarily suited for playing games". Apple consistently avoided stating that it was a home-computer company, and described the IIc as "a serious computer for the serious home user", despite competing against IBM's PCjr home computer. John Sculley denied that his company sold home computers; rather, he said, Apple sold "computers for use in
15704-605: The industrial metal card-cage enclosures used by the Altair and similar computers. The keyboard - a feature lacking on the Altair - was usually built into the same case as the motherboard . Ports for plug-in peripheral devices such as a video display, cassette tape recorders, joysticks , and (later) disk drives were either built-in or available on expansion cards . Although the Apple II had internal expansion slots, most other home computer models' expansion arrangements were through externally-accessible 'expansion ports' that also served as
15855-625: The instructions took 16 or 24 clock cycles to complete, the 1802 was not particularly fast. For comparison, the 6502 completes most instruction in 2 to 4 clock cycles, with the longest (official instruction) taking 7 cycles. Various suffixes to the CDP1802 part number denote technical specifications, including (A, B, & C) operating speed (3.2 MHz to 6.4 MHz), temperature (-40 °C to +85 °C, -55 °C to +125 °C), and voltage ranges (4V to 10.5V), package type (D, E, Q), and burn-in (X). These were somewhat standardized between
16006-665: The late 1970s, as well as the RCA Studio II video game console (one of the first consoles to use bitmapped graphics). The Edukit single-board computer trainer system, similar to an expanded COSMAC Elf , was offered by Modus Systems Ltd. in Britain in the early 1980s. Infinite Incorporated produced an 1802-based, S-100 bus expandable console computer trainer in the late 1970s called the UC1800, available assembled or in kit form. As part of 1802 retrocomputing hobbyist work, other computers have been built more recently (post-2000), including
16157-406: The late 1970s, the 6502-based Apple II had carved out a niche for itself in business, thanks to the industry's first killer app , VisiCalc , released in 1979. However, the Apple II would quickly be displaced for office use by IBM PC compatibles running Lotus 1-2-3 . Apple Computer 's 1980 Apple III was underwhelming, and although the 1984 release of the Macintosh introduced the modern GUI to
16308-402: The lines of 64 Amazing BASIC Games for the Commodore 64 . While most of the programs in these books were short and simple games or demos , some titles, such as Compute! ' s SpeedScript series, contained productivity software that rivaled commercial packages. To avoid the tedious process of typing in a program listing from a book, these books would sometimes include a mail-in offer from
16459-460: The market, it was not common until IBM-compatible computers adopted it. Throughout the 1980s, businesses large and small adopted the PC platform, leading, by the end of the decade, to sub-US$ 1000 IBM PC XT -class white box machines, usually built in Asia and sold by US companies like PCs Limited . In 1980, Wayne Green , the publisher of Kilobaud Microcomputing , recommended that companies avoid
16610-641: The microprocessor without affecting its operation. It has two separate 8-pin buses: an 8-bit bidirectional data bus and a time-multiplexed address bus , with the high-order and low-order 8-bits of the 16-bit address being accessed on alternate clock cycles. This contrasts with most designs of the era, like the MOS 6502 and Intel 8080 , which used a 16-bit address bus. The 1802 has a single bit , programmable and testable output port (Q), and four input pins that are directly tested by branch instructions (EF1-EF4). These pins allow simple input/output (I/O) tasks to be handled directly and easily programmed. Because
16761-406: The microprocessor's design) This setup allows R0 to be used for DMA and R1 to be used for Interrupts, if desired, allowing R7 through RF (hex) for general program usage. Because of the 16-bit address bus, and the 8-bit data bus, the sixteen general purpose registers are 16 bits wide, but the accumulator D-register is only 8 bits wide. The accumulator, therefore, tends to be a bottleneck. Transferring
16912-531: The new automatic pilot . After the death of Lawrence on December 13, 1923, the two firms were brought together in 1924. Then in January 1929 it was acquired by North American Aviation , who reincorporated it in New York as the Sperry Gyroscope Company, Inc . The company once again became independent in 1933 when it was spun-off as a subsidiary of the newly formed Sperry Corporation . The new corporation
17063-660: The new machine and its MS-DOS operating system. Even basic PCs cost thousands of dollars and were far out of reach for typical home computer users. However, in the following years, technological advances and improved manufacturing capabilities (mainly greater use of robotics and relocation of production plants to lower-wage locations in Asia) permitted several computer companies to offer lower-cost, PC-style machines that would become competitive with many 8-bit home-market pioneers like Radio Shack, Commodore, Atari, Texas Instruments, and Sinclair. PCs could never become as affordable as these because
17214-412: The opportunity to return to simpler systems. Inexpensive…microcomputers could open up vast new markets. Beginning in 1970, Weisbecker began the design of a small machine using RCA transistor-transistor logic (TTL) ICs to construct the processor. Other parts, switches and lamps and such, he had to buy from Radio Shack , deliberately spreading his purchases around four stores so no one would ask him why he
17365-592: The original FRED, known within RCA as System 00 by this time, using the new chipset to produce a greatly simplified single-board system known as then COSMAC ELF . Building instructions were described in an article in Popular Electronics magazine in 1976, and an expanded version with various upgrades in a second article in 1977. A unique feature of the ELF is that it did not require any read only memory (ROM) for startup, instead,
17516-671: The original Sperry Gyroscope building in Lake Success) performed work on a number of US government defense contracts. Sperry also managed the operation from 1961 to 1975 of the large Louisiana Army Ammunition Plant near Minden . In January 1972, Sperry took over the RCA Spectra 70 line of electronic digital computers (architectural cousins to the IBM System/360 ). In 1983, Sperry sold Vickers to Libbey Owens Ford (later to be renamed TRINOVA Corporation and subsequently Aeroquip-Vickers). At
17667-477: The platform, including a quiz-style educational product in partnership with Random House , one of the many companies that had been picked up by RCA's buying sprees. After a year of discussion, the company eventually decided to release two mass-market products based on the platform, a kit computer known as the COSMAC VIP , and a game console known as the RCA Studio II . The machines had been available since 1975, but
17818-516: The post-WWII era the company branched out into electronics, both aviation-related, and later, computers. The company was founded by Elmer Ambrose Sperry . The company was incorporated on April 14 1910 by Elmer Ambrose Sperry as the Sperry Gyroscope Company , to manufacture navigation equipment—chiefly his own inventions: the marine gyrostabilizer and the gyrocompass —at 40 Flatbush Avenue Extension in Downtown Brooklyn . During World War I
17969-545: The potential for computers in the home, having stated as early as 1955 that he expected they would one day be built into practically every device. The technology of the era made small embedded computers impossible, but the introduction of the integrated circuit (IC) in the 1960s changed things dramatically. In 1974 he described the possibilities in an IEEE Computer article: For 20 years computer hardware has become increasingly complex, languages more devious, and operating systems less efficient. Now, microcomputers afford some of us
18120-546: The price difference between old 8-bit technology and new PCs. Despite their higher absolute prices, PCs were perceived by many to be better values for their utility as superior productivity tools and their access to industry-standard software. Another advantage was the 8088/8086's wide, 20-bit address bus. The PC could access more than 64 kilobytes of memory relatively inexpensively (8-bit CPUs, which generally had multiplexed 16-bit address buses, required complicated, tricky memory management techniques like bank-switching ). Similarly,
18271-482: The processor's direct memory access (DMA) system was used to read front-panel switches directly into memory. RCA debated whether to introduce pre-packaged versions of the ELF to the market. While they debated, further development led to a simplified machine combining the ELF with a new display driver chip, the CDP1861 , to produce a game console . During this time, Joyce was hired by RCA to write several videogames for
18422-474: The program listings for the user to carry out. Applying a patch to modify software to be compatible with one's system, or writing a utility program to fit one's needs, was a skill every advanced computer owner was expected to have. During the peak years of the home computer market, scores of models were produced, usually as individual design projects with little or no thought given to compatibility between different manufacturers, or even within product lines of
18573-894: The range 0 to 255 (hex FF). There is no relative branching. The short branch always jumps within the page that contains the address byte. Long branches use full 16-bit addressing to support the 64K memory address space, and are the only 3-byte instructions. Skip instructions increment the PC by one for the unconditional Short Skip, or two for the Long Skips. Only the Long Skip has conditional branching. The processor does not have standard subroutine CALL address and RET instructions, though they can be simulated. The 16-register design makes possible some interesting subroutine call and return mechanisms, though they are better suited to small programs than general purpose coding. A few commonly used subroutines can be called quickly by keeping their address in one of
18724-491: The recording back through the modem to "load". Most cassette implementations were notoriously slow and unreliable, but 8" drives were too bulky for home use, and early 5.25" form-factor drives were priced for business use, out of reach of most home buyers. An innovative alternative was the Exatron Stringy Floppy , a continuous-loop tape drive which was much faster than a data cassette drive and could perform much like
18875-510: The same manufacturer used different disk formats. Almost universally, the floppy disk drives available for 8-bit home computers were housed in external cases, with their own controller boards and power supplies contained within. Only the later, advanced 8-bit home computers housed their drives within the main unit; these included the TRS-80 Model III , TRS-80 Model 4 , Apple IIc , MSX2 , and Commodore 128D . The later 16-bit machines, such as
19026-445: The same manufacturer. Except for the Japanese MSX standard, the concept of a computer platform was still forming, with most companies considering rudimentary BASIC language and disk format compatibility sufficient to claim a model as "compatible". Things were different in the business world, where cost-conscious small business owners had been using CP/M running on Z80 -based computers from Osborne , Kaypro , Morrow Designs , and
19177-473: The same market as the consoles. A home computer was often seen as simply a higher-end purchase than a console, adding abilities and productivity potential to what would still be mainly a gaming device. A common marketing tactic was to show a computer system and console playing games side by side, then emphasizing the computer's greater ability by showing it running user-created programs, education software, word processing, spreadsheet, and other applications, while
19328-418: The same price-reducing measures were available to all computer makers. Furthermore, software and peripherals for PC-style computers tended to cost more than those for 8-bit computers because of the anchoring effect caused by the pricey IBM PC. As well, PCs were inherently more expensive since they could not use the home TV set as a video display. Nonetheless, the overall reduction in manufacturing costs narrowed
19479-678: The same time, it acquired the Aircraft Radio Corporation from Cessna . On September 16, 1986, after the success of a second hostile takeover bid engineered by Burroughs Corporation CEO and former U.S. Secretary of the Treasury , Michael Blumenthal , Sperry Corporation merged with Burroughs Corporation. The newly merged company was renamed Unisys Corporation — a portmanteau of "united", "information", and "systems," while also referencing Sperry's well-known previous UNIVAC computer branding. The takeover came about even after Sperry used
19630-444: The side-effect that European and North American versions of the same home computer operated at slightly different speeds and different video resolution due to different television standards. Initially, many home computers used the then-ubiquitous compact audio cassette as a storage mechanism. A rough analogy to how this worked would be to place a recorder on the phone line as a file was uploaded by modem to "save" it, and playing
19781-414: The temporary United Nations headquarters from 1946 to 1952)—into the 1980s. In 1955, Sperry acquired Remington Rand and renamed itself Sperry Rand . Acquiring then- Eckert–Mauchly Computer Corporation and Engineering Research Associates along with Remington Rand, the company developed the successful UNIVAC computer series and signed a valuable cross-licensing deal with IBM . The company remained
19932-406: The term "home computer" in their advertising, as it "I feel is self-limiting for sales...I prefer the term "microcomputers" since it doesn't limit the uses of the equipment in the imagination of the prospective customers". With the exception of Tandy, most computer companies – even those with a majority of sales to home users – agreed, avoiding the term "home computer" because of its association with
20083-580: The time 1801 series CPU , offering a full PDP-11 compatibility and a fully functional Q-Bus slot, though at the cost of very anemic RAM and graphics. The Motorola 6809 was used by the Radio Shack TRS-80 Color Computer , the Fujitsu FM-7 , and Dragon 32/64 . Processor clock rates were typically 1–2 MHz for 6502 and 6809-based CPUs and 2–4 MHz for Z80-based systems (yielding roughly equal performance), but this aspect
20234-498: The transition from 5.25" to 3.5" format at the time (though 5.25" drives remained common on PCs until the late 1990s, due to existence of the large software and data archives on five-inch floppies). 5.25" drives were made available for the ST, Amiga, and Macintosh, otherwise 3.5" based systems with no other use for a 5.25" format. Hard drives were never popular on home computers, remaining an expensive, niche product mainly for BBS sysops and
20385-836: The two leaders in the US, Commodore and Atari, themselves felt compelled to enter the market with their own lines. They were only marginally successful compared to other companies that made only PCs. Still, later prices of white box PC clone computers by various manufacturers became competitive with the higher-end home computers (see below). Throughout the 1980s, costs and prices continued to be driven down by: advanced circuit design and manufacturing, multi-function expansion cards, shareware applications such as PC-Talk , PC-Write , and PC-File , greater hardware reliability, and more user-friendly software that demanded less customer support services. The increasing availability of faster processor and memory chips, inexpensive EGA and VGA video cards, sound cards , and joystick adapters also bolstered
20536-410: The values in these registers to be set and read via D, separately working the upper and lower 8-bits at a time. There are also instructions to perform increment and decrement of the entire 16-bit value, and a few instructions perform automatic increment and decrement, like LDA (load advance) and STXD (store via X and decrement). 16-bit register and value comparisons would also need to use the D register as
20687-572: The various source suppliers, including RCA, Intersil, Harris, Hughes Aircraft, and Solid State Scientific (SSS). Hughes used the HCMP prefix, and SSS used the SCP (and possibly BCP) prefix, instead of CDP, and had additional suffixes that have not been documented as of yet. (examples: CDP1802A, CDP1802ACE, CDP1802BCD, HCMP1802AP, SCP1802D) The 1802 is an 8-bit byte machine, with minimal support for 16-bit operations, except via 2-byte manipulation. The primary accumulator
20838-499: The viability of PC/DOS computers as alternatives to specially-made computers and game consoles for the home. From about 1985, the high end of the home computer market began to be dominated by "next-generation" home computers using the 16-bit Motorola 68000 chip, which enabled the greatly-increased abilities of the Amiga and Atari ST series (in the UK, the Sinclair QL was built around
20989-536: The work of a group of Stanford University inventors, led by Russell and Sigurd Varian , who had invented the klystron , and incorporated this technology and related inventions into their products. The company prospered during World War II as military demand skyrocketed, ranking 19th among US corporations in the value of wartime production contracts. It specialized in high technology devices such as analog computer –controlled bomb sights, airborne radar systems, and automated take-off and landing systems. Sperry also
21140-421: The world of digital technology. The line between 'business' and 'home' computer market segments vanished completely once IBM PC compatibles became commonly used in the home, since now both categories of computers typically use the same processor architectures, peripherals, operating systems, and applications. Often, the only difference may be the sales outlet through which they are purchased. Another change from
21291-543: The world. Due to the "price wars" being waged in the USA home computer market during the 1983-85 period, MSX computers were never marketed to any great extent in the USA. Eventually more advanced mainstream home computers and game consoles obsoleted the MSX machines. The MSX computers were built around the Zilog Z80 8-bit processor, assisted with dedicated video graphics and audio coprocessors supplied by Intel , Texas Instruments , and General Instrument . MSX computers received
21442-483: Was a holding company for a number of smaller entities such as the original Sperry Gyroscope, Ford Instrument Company , Intercontinental Aviation, Inc. , and others. The company made advanced aircraft navigation equipment for the market, including the Sperry Gyroscope and the Sperry Radio Direction Finder. It also moved into the hydraulics industry when it acquired Vickers, Inc. in 1937. Sperry supported
21593-561: Was also used for expansion or upgrades such as fast loaders . Application software on cartridge did exist, which loaded instantly and eliminated the need for disk swapping on single-drive setups, but the vast majority of cartridges were games. From the introduction of the IBM Personal Computer (ubiquitously known as the PC) in 1981, the market for computers meant for the corporate, business, and government sectors came to be dominated by
21744-528: Was buying so many parts. The design was running in October 1971, containing 100 chips spread over multiple circuit boards . The result, which he called FRED, ostensibly for Flexible Recreational Educational Device, was packaged into a box that was not unlike the Altair 8800 of a few years later, with toggle switches on the front panel for input, lamps for output, and later adding a hex pad keyboard. Weisbecker added new features continually and by 1972 it had gained
21895-467: Was created without a CDP1802 microprocessor chip or CDP1861 video chip using PIC microcontrollers . An online simulator of the COSMAC Elf (enhanced) written in JavaScript runs in the user's browser with no need to download. The RCA 1802 has a static core CMOS design with no minimum clock frequency , so that it can be run at very low speeds and low power, including a clock frequency of zero to suspend
22046-424: Was not emphasized by users or manufacturers, as the systems' limited RAM capacity, graphics abilities, and storage options had a more perceivable effect on performance than CPU speed. For low-price computers, the cost of RAM memory chips contributed greatly to the final product price to the consumer, and fast CPUs demanded expensive, fast memory. As a result, designers kept clock rates only adequate. In some cases, like
22197-417: Was that while those TV-monitors had difficulty displaying the clear and readable 80-column text that became the industry standard at the time, the only consumers who really needed that were the power users utilizing the machine for business purposes, while the average casual consumer would use the system for games only and was content with the lower resolution, for which a TV worked fine. An important exception
22348-466: Was the Radio Shack TRS-80 , the first mass-marketed computer for home use, which included its own 64-column display monitor and full-travel keyboard as standard features. This " peripherals sold separately" approach is another defining characteristic of the home computer era. A first-time computer buyer who brought a base C-64 system home and hooked it up to their TV would find they needed to buy
22499-492: Was the TI-99/4 , announced in 1979 with a 16-bit TMS9900 CPU. The TI was originally to use the 8-bit 9985 processor designed especially for it, but this project was cancelled. However, the glue logic needed to retrofit the 16-bit CPU to an 8-bit 9985 system negated the advantages of the more powerful CPU. Another exception was the Soviet Elektronika BK series of 1984, which used the fully-16-bit and powerful for
22650-831: Was the creator of the Ball Turret Gun mounted under the Boeing B-17 Flying Fortress and the Consolidated B-24 Liberator , as commemorated by the film Memphis Belle and the poem The Death of the Ball Turret Gunner . In 1944, Sperry sold the Brooklyn factory at 40 Flatbush Avenue Extension to the Howard clothing manufacturing company, which already had a smaller nearby factory. Postwar, Sperry expanded its interests in electronics and computing, producing
22801-424: Was the first place to see the appearance of new retail stores dedicated to selling only computer hardware, computer software, or both, and also the first place where such stores began to specialize in particular platforms. By 1982, an estimated 621,000 home computers were in American households, at an average sales price of US$ 530 (equivalent to $ 1,673 in 2023). After the success of the Radio Shack TRS-80 ,
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