Zenith Z-100

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Zenith Z-100
ManufacturerZenith Data Systems
Typepersonal computer
Release dateJune 1982; 37 years ago (1982-06)
Operating systemAvailable with CP/M and Z-DOS (non-IBM compatible MS-DOS variant)[1]
CPUDual processors: 8085 and 8088[1]
MemoryBase 128 KB RAM, expandable to 192 KB on board, to 768 KB with S-100 cards. (Video RAM was paged into the 64 KB block above 768 KB).
StorageTwo 320 KB 40-track double-sided 5.25-inch Floppy disk drives. Socket enabled direct plug-in of external 8-inch floppies.
Display25 lines × 80 characters[1]
Graphics640×225 bitmap display. 8-color (low-profile model), or monochrome upgradable to 8-level greyscale (all-in-one).[1]
Inputserial ports (2661 UART), one Centronics printer port (discrete TTL chips), light pen port
Power300 watts[1]

The Z-100 computer is a personal computer made by Zenith Data Systems (ZDS). It was a competitor to the IBM PC.

Design[edit]

The Zenith Data Systems Z-100 is a pre-assembled version of the Heathkit H100 electronic kit.[2] Configured as a family (Z-120 is an all-in-one model, with self-contained monitor), the Z-110 (called the low profile model) is similar in size to the cabinet of an IBM PC, XT, or AT, but a bit shorter, and configured with a raised cabinet molding on the top surface within which one placed one's display monitor, designed to keep it from sliding off to either side or back. Both models have a built-in keyboard that was tactilely and in appearance modeled on an IBM Selectric typewriter.

  • Dual processors: 8085 and 8088.
  • Available with CP/M and Z-DOS (non-IBM compatible MS-DOS variant).
  • Five S-100 expansion slots.
  • Two 320 KB 40-track double-sided 5.25-inch floppy disk drives. Socket enabled direct plug-in of external 8-inch floppies.
  • serial ports (2661 UART), one Centronics printer port (discrete TTL chips), light pen port.
  • 640×225 bitmap display. 8 colors (low-profile model), or monochrome upgradable to 8 greyscales (all-in-one).
  • Base 128 KB RAM, expandable to 192 KB on board, to 768 KB with S-100 cards. (Video RAM was paged into the 64 KB block above 768 KB).

The Z-100 is partially compatible with the IBM PC, using standard floppy drives. It runs a non-IBM version of MS-DOS, so generic MS-DOS programs run, but most commercial PC software use IBM BIOS extensions and do not run,[3] including Lotus 1-2-3.[4] Several companies offered software or hardware solutions to permit unmodified PC programs to work on the Z-100.

The Z-100 has unusually good graphics for its era,[3] superior to the contemporary CGA (640×200 monochrome bitmap or 320×200 4-color), IBM Monochrome Display Adapter (MDA) (80×25 text-only), and on par with the Hercules Graphics Card (720×348 monochrome). Early versions of AutoCAD were released for the Z-100 because of these advanced graphics.[5]

Aftermarket vendors also released modifications to upgrade mainboard memory and permit installation of an Intel 8087 math coprocessor.

Uses[edit]

In 1983, Clarkson College of Technology (now Clarkson University) became the first college in the nation to give each incoming freshman a personal computer. The model issued to them was the Z-100.[6][7][8]

Reception[edit]

Jerry Pournelle in 1983 praised the Z-100's keyboard, and wrote that it "had the best color graphics I've seen on a small machine".[3][4] Although forced to buy a real IBM PC because of the Z-100 and other computers' incomplete PC compatibility,[4] he reported in December 1983 that a friend who was inexperienced with electronic kits was able to assemble a H100 in a day, with only the disk controller needing soldering.[2]

References[edit]

  1. ^ a b c d e Zenith Challenges IBM's share of micro market, By Paul Freiberger, Page 35, InfoWorld, 13 Sep 1982
  2. ^ a b Pournelle, Jerry (December 1983). "Buddy, Can You Spare a Door Latch?". BYTE. p. 59. Retrieved 20 October 2013.
  3. ^ a b c Pournelle, Jerry (June 1983). "Zenith Z-100, Epson QX-10, Software Licensing, and the Software Piracy Problem". BYTE. p. 411. Retrieved 20 October 2013.
  4. ^ a b c Pournelle, Jerry (September 1983). "Eagles, Text Editors, New Compilers, and Much More". BYTE. p. 307. Retrieved 2019-04-07.
  5. ^ One Company's CAD Success Story, InfoWorld, 3 December 1984, retrieved 19 July 2014
  6. ^ "Computers to Come With Books at Drexel U." New York Times. October 28, 1982. Retrieved 9 December 2013.
  7. ^ "Supershorts". Computer World. August 15, 1983. Retrieved 9 November 2011.
  8. ^ "Clarkson College to Issue Computers to Student Body" (PDF). Silicon Gulch Gazette. February 1983. Retrieved 9 November 2011.

External links[edit]