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Kaypro Corporation
Company typeCorporation
IndustryComputer hardware
HeadquartersSolana Beach, California
Key people
Andrew Kay

Kaypro Corporation was an American home and personal computer manufacturer based in Solana Beach in the 1980s. The company was founded by Non-Linear Systems (NLS) to compete with the popular Osborne 1 portable microcomputer. Kaypro produced a line of rugged, "luggable" CP/M-based computers sold with an extensive software bundle which supplanted its competitors and quickly became one of the top-selling personal computer lines of the early 1980s.

Kaypro was exceptionally loyal to its original customer base but slow to adapt to the changing computer market and the advent of IBM PC compatible technology. It faded from the mainstream before the end of the decade and was eventually forced into bankruptcy in 1992.


Kaypro began as Non-Linear Systems, a maker of electronic test equipment, founded in 1952 by Andrew Kay, the inventor of the digital voltmeter.[1][2]

In the 1970s, NLS was an early adopter of microprocessor technology, which enhanced the flexibility of products such as production-line test sets. In 1981, Non-Linear Systems began designing a personal computer, called KayComp, that would compete with the popular Osborne 1 transportable microcomputer. In 1982, Non-Linear Systems organized a daughter company named the Kaypro Corporation.[citation needed]

Boy with Kaypro II, 1984

Despite being the first model to be released commercially, the original system was branded as the Kaypro II (at a time when one of the most popular microcomputers was the Apple II). The Kaypro II was designed to be portable like the Osborne, contained in a single enclosure with a handle for carrying.[3] Set in an aluminum case, with a keyboard that snapped onto the front, covering the 9" CRT display and drives, it weighed 29 pounds (13 kg) and was equipped with a Zilog Z80 microprocessor, 64 kilobytes of RAM, and two 5¼-inch double-density single-sided floppy disk drives. It ran Digital Research, Inc.'s CP/M operating system, the industry standard for 8-bit computers with 8080 or Z80 CPUs, and sold for about US$1,795 (equivalent to $5,700 in 2023).[citation needed]

The company advertised the Kaypro II as "the $1,595 computer that sells for $1,595".[4] Although some of the press mocked its design—one magazine described Kaypro as "producing computers packaged in tin cans"[5]—others raved about its value, noting that the included software bundle had a retail value over $1,000 by itself, and by mid-1983 the company was selling more than 10,000 units a month, briefly making it the fifth-largest computer maker in the world.[citation needed]

The Kaypro II was part of a new generation of consumer-friendly personal computers that were designed to appeal to novice users who wanted to perform basic productivity on a machine that was relatively easy to set up and use. It managed to correct most of the Osborne 1's deficiencies: the screen was larger and showed more characters at once, the floppy drives stored over twice as much data, and it was better-built and more reliable.[citation needed]

Computers such as the Kaypro II were widely referred to as "appliance" or "turnkey" machines; they offered little in the way of expandability or features that would interest hackers or electronics hobbyists and were mainly characterized by their affordable price and a collection of bundled software. While it was easy to obtain and use new software with the Kaypro II—there were thousands of application programs available for CP/M, and every Kaypro 8-bit computer had a full 64 KB of RAM, enough to run virtually any CP/M program—the hardware expandability of this computer was nearly nonexistent. The Kaypro II had no expansion slots or system bus connector, no spare ROM socket, no peripheral bus, only two I/O ports,[6] and an ASCII text-only green-on-black video display, of 80 x 24 characters, that could only be shown on the internal 9" CRT monitor (despite the video being scanned at NTSC TV-compatible rates).[citation needed]

In contrast, one feature that was favorable to electronics hobbyists was that all the chips on the Kaypro II mainboard were installed in sockets, not soldered to the board, making it easy to repair the machines or even to splice custom circuits into the stock logic (temporarily or permanently). Also, while Kaypro machines were generally not upgradeable without factory-unauthorized custom modification, some Kaypro computers that came with single-sided floppy disk drives could be upgraded to double-sided drives, and some that came with only one floppy drive could have a second drive added. (The Kaypro II itself may be upgradeable or not to double-sided drives depending on which of two possible mainboard types is installed in the machine.[7])

Despite their limitations, the boxy units were so popular that they spawned a network of hobbyist user groups across the United States that provided local support for Kaypro products; the company worked with the user groups and would have a salesman drop by if in the area.[citation needed]

Kaypro's success contributed to the eventual failure of the Osborne Computer Corporation and Morrow Designs. A more rugged seeming, "industrialized" design than competitors such as the Osborne made the Kaypro popular for commercial/industrial applications. Its RS-232 port was widely used by service technicians for on-site equipment configuration, control and diagnostics. The relatively high quality of mechanical fabrication seen in the aluminum-cased Kaypro 8-bit computers was a natural outgrowth of NLS's prior business building professional and industrial electronic test instruments.[citation needed]

The version of CP/M included with the Kaypro could also read the Xerox 810's single-sided, single-density 86k floppy format. The Kaypro 8-bit computers used the popular Western Digital FD1793 floppy disk controller; any disk format that the FD1793 could read and/or write (at 250 kbit/s), the Kaypro II, 4, 10, and similar models are capable of reading and/or writing. Theoretically, any soft-sector MFM or FM floppy format that is within the limits of the FD1793[8] could be read or written if the user wrote their own utility program.[citation needed]

Kaypro published and subsidized ProFiles: The Magazine for Kaypro Users, a monthly, 72-page, four-color magazine that went beyond coverage of Kaypro's products to include substantive information on CP/M and MS-DOS; frequent contributors included Ted Chiang, David Gerrold, Robert J. Sawyer, and Ted Silveira.[9] Keeping its namesake, the publication profiled Kaypro founder Andrew Kay and software engineer Stephen Buccaci.[10]

Another popular magazine that covered Kaypro computers was Micro Cornucopia, published in Bend, Oregon.[11]

Arthur C. Clarke used a Kaypro II to write and collaboratively edit (via modem from Sri Lanka) his 1982 novel 2010: Odyssey Two and the later film adaptation.[12][13][14] A book, The Odyssey File - The Making of 2010, was later released about the collaboration.

Following the success of the Kaypro II, Kaypro moved on to produce a long line of similar computers into the mid-1980s. Exceedingly loyal to its original core group of customers, Kaypro continued using the CP/M operating system long after it had been abandoned by its competitors.

In late 1984, Kaypro introduced its first IBM PC compatible, the Kaypro 16 transportable. While admitting that "it's what our dealers asked for", the company stated that it would continue to produce its older computers.[15] This was followed by other PC compatibles: the Kaypro PC, Kaypro 286i (the first 286 IBM PC AT compatible),[16] the Kaypro 386, and the Kaypro 2000 (a rugged aluminum-body battery-powered laptop with a detachable keyboard). The slow start into the IBM clone market would have serious ramifications for the company.

After several turbulent years, with sales dwindling, Kaypro filed for Chapter 11 bankruptcy in March 1990.[17] Despite restructuring, the company was unable to recover and filed for Chapter 7 bankruptcy in June 1992. In 1995, its remaining assets were sold for US$2.7 million.[18]

The Kaypro name briefly re-emerged as an online vendor of Microsoft Windows PCs in 1999, but was discontinued in 2001 by its parent company Premio Inc. because of sluggish sales.[19]

Kaypro computers


A Kaypro II displaying the Kaypro Wikipedia page using Lynx over a serial connection
A Kaypro II motherboard

The Kaypro II has a 2.5 MHz Zilog Z80 microprocessor; 64 KB of RAM; two single-sided 191 KB 5¼-inch floppy disk drives (named A: and B:); and an 80-column, green monochrome, 9" CRT that was praised for its size and clarity (the Osborne 1 had a 5" display).[20]

Early in the Kaypro's life, there was a legal dispute with the owner of the Big Board computer, who charged that the Kaypro II main circuit board was an unlicensed copy or clone.[citation needed]

The outer case is constructed of painted aluminum. The computer features a large detachable keyboard unit that covers the screen and disk drives when stowed. The computer could fit into an airline overhead rack.[20] This and other Kaypro computers (except for the Kaypro 2000) run off regular AC mains power and are not equipped with a battery.

The Kaypro IV and later the Kaypro 4 have two double-sided disks. The Kaypro 4 was released in 1984, and was usually referred to as Kaypro 4 '84, as opposed to the Kaypro IV, released one year earlier and referred to as Kaypro IV '83. The Kaypro IV uses different screen addresses than the Kaypro II, meaning software has to be specific to the model.

A Kaypro 10 portable computer.

The Kaypro 10 followed the Kaypro II, and is much like the Kaypro II and Kaypro 4, with the addition of a 10 megabyte hard drive (dually partitioned A: and B:) and replacing one of the two floppy drives (the remaining drive being addressed as C:). The Kaypro 10 also eliminated the complicated procedures to turn the computer on and off often associated with hard disk technology.[21]

Kaypro later replaced their CP/M machines with the MS-DOS-based Kaypro 16, Kaypro PC and others, as the IBM PC and its clones gained popularity. Kaypro was late to the market, however, and never gained the kind of prominence in the MS-DOS arena that it had enjoyed with CP/M. Instead, Kaypro watched as a new company—Compaq—grabbed its market with the Compaq Portable, an all-in-one portable computer that was similar to Kaypro's own CP/M portables with the exception of running MS-DOS with near 100% IBM PC compatibility. The Compaq was larger and less durable—whereas the Kaypro had a heavy-gauge aluminium case, the Compaq case was plastic, with a thin-gauge aluminum inner shield to reduce radio frequency interference—but rapidly took over the portable PC market segment.

The 1985 introductions of the Kaypro 286i, the first IBM PC AT clone,[22] and the Kaypro 2000,[23] one of the first laptop computers (an MS-DOS system with monochrome LCD and durable aluminum case), did little to change Kaypro's fortunes. Kaypro's failure in the MS-DOS market and other corporate issues helped lead to the company's eventual downfall.


CP/M was the standard operating system for the first generation of Kaypros. The first application software that came with the Kaypro II included a highly unpopular word processor called Select that was quickly dropped in favor of a proto office suite from Perfect Software which included Perfect Writer, Perfect Calc, Perfect Filer, and Perfect Speller, as well as Kaypro's own S-BASIC compiler (which produced executable .com files). Perfect Filer featured non-relational, flat-file databases suitable for merging a contact list with form letters created in Perfect Writer.

Perfect Writer was initially a rebranded version of the MINCE and Scribble software packages from Mark of the Unicorn, which are CP/M implementations of Emacs and Scribe, ported from their original minicomputer-based versions using BDS C. Later, MBasic (a variant of Microsoft BASIC) and The Word Plus spellchecker were added to the model II suite of software. Word Plus included a set of utilities that could help solve crossword puzzles or anagrams, insert soft hyphens, alphabetize word lists, and compute word frequencies. Another utility program called Uniform allowed the Kaypro to read disks formatted by Osborne, Xerox, or TRS-80 computers.

The initial bundled applications were soon replaced by the well-known titles WordStar, a word processor, with MailMerge, originally a third-party accessory, for personalised mass mailings (form letters), the SuperCalc spreadsheet, two versions of the Microsoft BASIC interpreter, Kaypro's S-BASIC, a bytecode-compiled BASIC called C-Basic, and the dBase II relational database system.

Data could be moved between these programs relatively easily by using comma delimited format files (now more commonly known as CSV files), which enhanced the utility of the package. The manuals assumed no computer background, the programs were straightforward to use, and thus it was possible to find the CEO of a small company developing the applications needed in-house.

The Kaypro II and later models also came with some games, including versions of old character-based games such as Star Trek; a few were arcade games re-imagined in ASCII, including CatChum (a Pac-Man-like game), Aliens (a Space Invaders-like game) and Ladder (a Donkey Kong-like game).

If bought separately, this software would have cost more than the entire hardware and software package together. The Kaypro II was a very usable and (at the time) powerful computer for home or office, even though the painted metal case made it look more like a rugged laboratory instrument than an office machine. It enjoyed a reputation for durability.

Later Kaypro CP/M models came with even more software. In 1984, BYTE magazine observed "Kaypro apparently has tremendous buying and bargaining power," noting the Kaypro 10 came with both WordStar and Perfect Writer, plus "two spelling checkers, two spreadsheets, two communications programs and three versions of BASIC".[24]

Later MS-DOS Kaypro computers offered a similar software bundle.


InfoWorld in 1982 described Kaypro II as "a rugged, functional and practical computer system marketed at a reasonable price." The reviewer called the hardware "first-rate," writing that he had used the computer indoors and outdoors in several countries without fault, and praising the keyboard and screen. Deficiencies included the heavy weight and mediocre documentation.[25]

Jerry Pournelle wrote in BYTE in 1983 that he was able to use a Kaypro II without the documentation. Although he preferred the much more expensive Otrona Attaché, Pournelle called the Kaypro's hardware "impressive" and "rugged," approving of the keyboard layout and "certainly the largest screen you'll ever get in a portable machine."[20] A later review by the magazine described the computer as "best value," citing the rugged hardware design, sharp display, keyboard, documentation, and the extensive bundled software.[26] In 1984 Pournelle stated that "For those without much money, there's no real choice ... you need a Kaypro, which has become both the VW and Chevrolet of the micro industry".[27]

BYTE stated in 1984 that while the Kaypro 10 was "not a technologically innovative machine ... the equipment and power delivered for the price are outstanding", noting that the $2,795 computer "costs less than many stand-alone hard-disk drives". It approved of the "beautiful" monitor as an improvement from the Kaypro II's, and the extensive menus for running software on the hard drive without using the command line. The magazine criticized the "unacceptable" user's guide, and predicted that the large software bundle would be "stupefying" to novice users, but concluded that the computer was an "exceptional value for the money. It should be considered by anyone interested in hard-disk capacity or performance at an excellent price."[24]

Creative Computing in December 1984 chose the Kaypro 2 as the best transportable computer under $2,500, praising the "incredible array of software" included for "an astounding $1,295" price.[28]

Kaypro by model and year

Kaypro's nomenclature was odd, with the numerical designations for their machines having more to do with the capacity of the drives than the order they were produced. Kaypro also released several different models with the same names, perhaps hoping to capitalize on the name recognition of their older machines. As a result, identifying exactly which model a Kaypro is often requires an inspection of their hardware configuration.

All of the computers listed below are of the portable type unless otherwise noted.


  1. ^ Freeman, Mike (3 September 2014). "Computer pioneer Andrew Kay dies at 95". San Diego Union-Tribune. Retrieved 17 October 2023.
  2. ^ Markoff, John (2014-09-05). "Andrew Kay, Pioneer in Computing, Dies at 95". The New York Times. ISSN 0362-4331. Retrieved 2023-10-17.
  3. ^ The term also implies that the weight of the machine was low enough that a typical adult was capable of lifting it. In the early 1980s, the alternative to a "portable" computer was a computer designed to be installed at a fixed location: such a machine was typically impractical to transport without some disassembly and was difficult or impossible for a single person to carry out of a room, let alone to another building, in a single trip. The Kaypro II (like the Osborne 1, the later Compaq Portable, and the original Apple Macintosh) was portable in the way a portable typewriter—one of the machines that personal computers replaced—was portable, and should not be confused with the meaning of modern term 'mobile' (i.e. 'mobile phone'). The standard Kaypro II (like the other three portable machines mentioned) was powered by AC only; it was meant to be moved from one building to another—e.g. from one's home to one's office or a friend's home—to be quickly set up and used on a desk or tabletop there.
  4. ^ "The $1,595 computer that sells for $1,595". BYTE (advertisement). January 1984. p. 390. Retrieved 20 January 2015.
  5. ^ Dickinson, John (July 1986). "Kaypro 2000". PC Magazine. Vol. 5, no. 13. pp. 116–117. Retrieved 9 January 2015.
  6. ^ one minimal Centronics-type printer port and one RS-232 serial port with a baud rate up to 19200, though the CPU might not have been able to sustain that serial data rate
  7. ^ Some Kaypro II units—probably the earliest ones—have the 81-110 mainboard, which lacks the connection of the side-select signal and so can only control single-sided drives. Other Kaypro II units have the 81-240 mainboard: this is the same board used in the Kaypro 4, so it has that signal connected and can support double-sided drives. However, the Kaypro II and Kaypro 4, which have no equipment differences other than the installed floppy disk drives, also had different monitor ROM versions (as of Sept. 1985), so it might be necessary to replace that ROM at the same time double-sided drives are installed in the Kaypro II, effectively completing its conversion to a Kaypro 4 (except for the exterior finish). In the 1980s, the Kaypro 4 ROM could have been bought from Kaypro. In the 21st century, 8-bit Kaypro ROM images can be found on the web, but a vintage original Kaypro II might retain more value if kept in the original stock condition. Fortunately, all modifications discussed here are fully reversible, provided the original ROM is kept and stored appropriately to protect it. Technical fact source: Kaypro Technical Manual, Sep. 1985, Kaypro part # 1484-F.
  8. ^ e.g. sector data sizes of only 128, 256, 512, or 1024 bytes, certain minimum gap lengths, and other constraints as described in the Western Digital FD197X datasheet
  9. ^ Many issues are archived at, retrieved 2014-09-10
  10. ^ "(Cover)". PROFILES. Vol. 2, no. 2. Kaypro Corp. September 1984. Retrieved 2020-08-20.
  11. ^ 55 issues are archived at, retrieved 2014-09-10
  12. ^ "Kaypro II computer".
  13. ^ "Biography for Arthur C. Clarke". IMDb.
  14. ^ "About Sir Arthur". The Arthur C. Clarke Foundation. Archived from the original on 2011-07-25.
  15. ^ Sanger, David E. (1984-11-15). "At Computer Show, Many Retrenching". The New York Times. Retrieved 24 October 2013.
  16. ^ Chin, Kathy (22 September 2011). "Kaypro introduces first of the PC AT clones". InfoWorld. Vol. 7, no. 9. pp. 15–16.
  17. ^ Brownstein, Mark (March 12, 1990). "Kaypro to Reorganize, Files for Chapter 11". Infoworld. Vol. 12, no. 11.
  18. ^ US Court of Appeals for the 9th Circuit (2000) Arrow Electronics v. Justus 9955210 Archived 2006-02-18 at the Wayback Machine. Retrieved April. 1, 2006.
  19. ^ Mainelli, Tom (May 22, 2001). "PC Pioneer Kaypro Dies, Again". PC World. Archived from the original on January 16, 2014. Retrieved March 15, 2007. Nostalgia isn't enough to make a PC brand profitable--just ask the folks at Kaypro. PC manufacturer Premio, which owns Kaypro and builds its systems, will continue operations and will honor all Kaypro service and warranty agreements, says company spokesperson Laura Miller.
  20. ^ a b c Pournelle, Jerry (Jan 1983). "Burnouts, Bargains, and Two Sleek Portables". BYTE. Vol. 8, no. 1. p. 432. Retrieved 2017-05-13.
  21. ^ "The Kaypro 10; more than just a big screen portable".
  22. ^ Kaypro PC & 286i, OLD-COMPUTERS.COM Museum
  23. ^ "Kaypro 2000". OLD-COMPUTERS.COM Museum.
  24. ^ a b McMahon, Steve (May 1984). "The Kaypro 10". BYTE. Vol. 9, no. 5. pp. 206–224. Retrieved 10 September 2016.
  25. ^ Derfler, Frank J. (1982-10-18). "Kaypro II—a low-priced, 26-pound portable micro". InfoWorld. Vol. 4, no. 41. pp. 59–61. Retrieved 22 October 2013.
  26. ^ Fager, Roger; Bohr, John (September 1983). "The Kaypro II". BYTE. Vol. 8, no. 9. p. 212. Retrieved 20 October 2013.
  27. ^ Pournelle, Jerry (Aug 1984). "Between Conventions". BYTE. Vol. 9, no. 8. p. 313. Retrieved 24 February 2016.
  28. ^ Ahl, David H. (December 1984). "Top 12 computers of 1984". Creative Computing. Retrieved 2019-03-16.
  29. ^ a b "Kaypro / CP/M Versions / Part 1". 2017-04-06. Retrieved 2022-05-19.
  30. ^ "Kaypro 2000". 2017-04-06. Retrieved 2021-09-14.
  31. ^ Lockwood, Russ (July 1985). "Kaypro 286i; the first PC AT compatible". Creative Computing. Vol. 11, no. 7. p. 25. Retrieved October 7, 2009.