Osborne 1
Introduced:April 1981
Price:US $1,795
Weight:24.5 pounds
CPU:Zilog Z80 @ 4.0 MHz
RAM:64K RAM
Display:built-in 5" monitor
53 X 24 text
Ports:parallel / IEEE-488
modem / serial port
Storage:dual 5-1/4 inch, 91K drives
OS:CP/M



Released in 1981 by the Osborne Computer Corporation, the Osborne 1 is considered to be the first true portable computer - it closes-up for protection, and has a carrying handle. It even has an optional battery pack, so it doesn't have to plugged into the 110VAC outlet for power.

While quite revolutionary, the Osborne does have its limitations. For example, the screen is only 5" (diagonal) in size, and can't display more than 52 characters per line of text. To compensate, you can actually scroll the screen display back and forth with the cursor keys to show lines of text up to 128 characters wide.

The Osborne was designed with transportation in mind - it had to be rugged and able to survive being moved about. That's one reason that the screen is so small - a larger and heavier screen would be more susceptable to damage.

The two pockets beneath the floppy drives work great for floppy disk storage, although the Osborne modem also fits perfectly in the the left pocket and plugs into the front-mounted "modem" port.

Designed as a true portable computer system - it can be considered airline carry-on luggage, and it will fit under the passenger seat of any commercial airliner.

Here is the Osborne without the case - now you know the real reason the screen is so small. There's not much room left with those two full-height floppy drives.
While the Osborne was a good deal at $1795, it also came bundled with about $1500 of free software:
  • CP/M System
  • CP/M Utility
  • SuperCalc spreadsheet application
  • WordStar word processing application with MailMerge
  • Microsoft MBASIC programming language
  • Digital Research CBASIC programming language

  • The Osborne was a huge overnight success, with sales reaching 10,000 units a month.
    In September 1981, Osborne Computer Company had its first US$1 million sales month.


    Available options include the Osborne DATACOM modem.
  • The Osborne modem and COMM-PAC software gives you access to more than 200 electronic bulletin boards across the country (well, in 1982, that is).
  • Data transfer rate is 300 baud.
  • The modem fits in the diskette pocket below floppy drive A.
  • It fits in both the original "tan case" and the newer "blue case" Osborne (see below), but the diskette pocket in the "blue case" is smaller, so the eight alignment tabs must be 'carefully snapped off'.



  • Also available is the Double-Density Disk Drive Option. This is an additional circuit board which must be installed inside the system.
  • Doubles the amount of data storage per diskette.
  • Recognizes these formats:
    -- Osborne 1 single density - 92K per diskette
    -- Osborne 1 double density - 182K per diskette
    -- Xerox 820 single density - 82K per diskette
    -- Cromemco single density - 80K per diskette
    -- IBM Personal Computer (CP/M-86 format) - 156K per diskette
    -- DEC VT-180 - 171K per diskette



  • Seen above is the second release of the Osborne portable. It has a sturdier case and a slightly different look - double-density floppy-drives are optional.

    Intentional or not, the "new" Osborne has a very military-like appearance, with its square face, dark blue color, and its many knobs and compartments.


    In 1982, the Osborne Computer Company announced a successor, the Executive model OCC-2 (seen here to the right), with a larger screen and a cooling fan.

    Shortly thereafter, they announced the next system, the Vixen, a portable running the CP/M operating system.

    Unfortunately, potential customers stopped buying the Osborne 1, waiting for the Executive and the Vixen, which wasn't even ready to ship yet. Additionally, the new Kaypro II was now available with a larger screen for less money. Osborne sales plummeted and Osborne quickly ran out of money and filed for bankruptcy in September of 1983.

    It probably wasn't the company's fault, since by this time most of the serious computer users were gravitating towards the new IBM PC, which had already been available since 1981.

    Anything that wasn't IBM compatible was bound to fail. In 1983, the Compaq Portable came out - a portable computer similar to the Osborne, except that it was IBM compatible and ran MS-DOS. It was a great success.

    Related Links

  • Osborne Computer Corporation from Classic Computer Magazine Archive
  • 15 Years Ago in BYTE
  • From Wikipedia, the free encyclopedia
  • Osborne Computer Libraries
  • The inventor of the mobile computer dies...


  • History of the Osborne Computer Corporation

    • 1971: In November, Intel released the 4004, the first microprocessor chip. Documentation manuals were written by Adam Osborne who later founded the Osborne Computer Company.
    • 1980: March - At the West Coast Computer Faire, Adam Osborne approaches Les Felsenstein with the idea of starting a computer company.
    • 1981: January - Osborne Computer Corporation is incorporated
    • 1981: April - Adam Osborne, of Osborne Computer Corporation, introduces the Osborne 1 Personal Business Computer at the West Coast Computer Faire
    • 1981: September - Osborne Computer Company has its first US$1 million sales month.
    • 1982: August - Microsoft releases Multiplan for the Apple II and the Osborne I.
    • 1982: In the first 8 months since its introduction, 11,000 Osborne 1 computers ship.
    • 1983: March - Osborne Computer introduces The Osborne Executive and the Executive II portable computers.
    • 1983: September - Osborne Computer Corp. files for Chapter 11 bankruptcy protection
      Source: Chronology of Events in the History of Microcomputers




    Adam Osborne


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