Xerox 820
Introduced:June 1981
CPU:Zilog Z80-A @ 2.5MHz
Memory:64K RAM
Display:12-inch monochrome CRT
80 x 24 text
Ports:floppy drive, keyboard
printer, serial comms
Storage:external floppy drive
OS:CP/M 2.2

Xerox 820
Personal Computer

During the 1970's, Xerox - one of America's largest corporations and a member of the Fortune 500 ever since 1963 - inventing such things as computer "ethernet" networking, the laser printer, and the world's first computer with a GUI Graphical User Interface (like Windows).

The Xerox Alto was an early computer created by Xerox PARC in 1973 - it was clearly ahead of its time, with ethernet networking, a WYSIWYG (What You See Is What You Get) graphical user interface, icons, bit-mapped display, scalable fonts, a mouse, and a laser printer. Although over 1,000 Altos were eventually built, it was never intended to be a commercial product - the Altos were all used in-house or donated to universities and government facilities. Basically, PARC built what PARC wanted.

In 1979, Steve Jobs from Apple Computer was allowed to tour the PARC research lab in exchange for Xerox to purchase $1,000,000 of cheap pre-IPO Apple stock. He took what he saw there and ran with it - and in 1983 Apple released the Apple Lisa, based on "Alto technology". At $10,000, the Lisa was too different and expensive to be a success, but that's another story.

In 1981, Xerox released two new computer system - the first is the advanced Xerox 8010 "Dandelion" workstation - a $15,000 off-shoot of the Alto. The 8010 is commonly referred to as the "Star", but that really only refers to the software, which was later renamed as "ViewPoint", then to "GlobalView".

The second system released in 1981 was the Xerox 820 - AKA the "Worm" - a cheaper $2,950 system for the office. The "Worm" is a jab at Apple computers - the "worm" will eat their "apple".

The Xerox 820 was designed to be an immediate success - the hardware is based on an already proven design - the Ferguson Big Board, and the software is CP/M - at that time, the world's most popular computer operating system.

There was really nothing new or unexpected with the Xerox 820, but that was the problem - it was mediocre, bland and boring, especially for the high price of $2,995. The system speed was slow at only 2.5MHz, there were no expansion slots or capability, and the single-sided single-density (SSSD) 5 1/4-inch floppy drives only held 81KB of data each. SSSD 8-inch floppy drives were also available - they held 241KB each - but they cost an additional $800.

Although heavy and sturdy, the Xerox 820 is somewhat compact, with all of the computer circuitry - the motherboard - enclosed within the display unit. The floppy drive storage system is an external cabinet, but at least the user can position it where it is most convenient. The rather large keyboard is also a separate assembly, and can be positioned comfortably anywhere within close proximity to the monitor.

The data storage is on external 5 1/4-inch (Shugart SA450) or 8-inch (Shugart SA850) floppy drives. The only officially supported printer is the Diablo 630 letter-quality daisywheel printer, available for $2710. Both Shugart and Diablo Data Systems were companies owned by Xerox.

When first turned on, the user is presented with these options:
  • "Enter A for BOOT" - Load software from floppy drive unit zero.
  • "Enter T for TYPEWRITER" - Everything the user types is printed on the printer.
  • Additional monitor options include: <D>ump, <M>emory, <X>test, <F>ill, <C>opy, <G>oto, <R>ead, <I>nput, <O>utput.

    The next year, in May 1982, Xerox introduced the Xerox 820-II system, shown here - now faster and better, but not cheaper. The 820-II now runs at a respectable 4.0MHz processor speed, and sports two new expansion ports on the motherboard. One of the expansion ports holds a controller card for the external data storage drives, which can be dual 5 1/4-inch floppy drives, dual 8-inch floppy drives, or a 50-pound 8-inch floppy and rigid drive combo. The rigid drive is the Shugart SA-1004 8-inch 10MB hard drive. Drives A: to D: are the default floppy drive assigns, drives E: to H: are the default hard drive partitions. Floppy drives can be single- or double-sided , single- or double-density.

  • The standard Xerox 820-II with dual 5 1/4-inch floppy drives was introduced at $3,295.
  • With the 8-inch floppy drive/rigid drive combo - $7,695.
  • Optional 20cps Sabre daisywheel printer - $1,595 extra.
  • Optional 40cps Diablo daisywheel printer - $2,395 extra.

  • When 820-II is first turned on, the user is presented with a menu:
  • L - "Load" - Load software from an attached floppy drive - "LA"=load from drive A:, "LB"=load from drive B:, etc.
  • H - "Host Terminal" - Operate as a dumb-terminal to communicate with another computer system.
  • T - "Typewriter" - Everything the user types is printed on the attached printer.

  • By this time, the IBM PC had been released and available for one year, and was become extremely popular and taking over the market. To compete, in mid 1983 Xerox announced an upgrade to the 820-II system to include MS-DOS compatibilty. This new system is known as the Xerox 16/8 Personal Computer. Hardware-wise, is was a simple upgrade - an Intel 8086-based CPU card with 128K of RAM was added to the second expansion slot (right-most, as seen from the back) on the motherboard, as seen below.

    The 16/8 can simultaneously run two separate programs, both at the same time - one on the added 8086 card, the other using the built-in CPU on the motherboard. Included software is the original 8-bit CP/M-80, and now the 16-bit CP/M-86 and MS-DOS 2.0. Prices are from $3,395 to $5,295 depending on data storage options.

    By early 1985, after making little impact on the market, Xerox stopped manufacturing their Xerox 820 line of office computers.

    Related Links

  • BYTE Magazine - September 1981
  • NYT announcement - June 1981
  • "Advantages of the Xerox 820 Microcomputer over the IBM PC" - June 1982
  • InfoWorld review - June 1982
  • Xerox documents from
  • MCC Workshop
  • "A Look at the Hotness from 30 Years Ago" - from

  • Xerox 820-II motherboard

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