Heathkit H89

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Heathkit H89
Heathkit H89 Computer.jpg
Basic data
processor 2 × Z80
Clock frequency 2 MHz
R.A.M. 64 kB
monitor 12 "B / W CRT
Mass storage 5.25 "floppy disk drive
(hard-sectored, 100 kB)
Interfaces 3 × serial, 1 × parallel, 1 × external floppy disk drive
Operating systems HDOS , CP / M , MP / M
price * WH89: US $ 2,295
* H89: US $ 1,595 (as of 1979)

The H89 was one of the first personal computers for the home user. In 1979 it was brought onto the market by the Heathkit company under the designation H89 (as a kit) or WH89 (as a finished device, W for Wired). After the takeover of Heathkit by Zenith Data Systems , Zenith sold it under the name Z-89.

technology

Zenith Z-89

The computer had two Zilog Z80 processors with a clock frequency of 2 MHz each and worked with the HDOS and CP / M operating systems . One of the processors was responsible for the terminal functions. He combined a 12 "- CRT - monitor , keyboard and floppy disk drives in a housing floppy disk drives were at a. Controller connected for hartsektorierte disks and processed hartsektorierte 5.25" - floppy disks having a capacity of 100 kB.

Various floppy disk stations were offered as accessories:

  • The H / Z-77 and H / Z-87 models provided two additional floppy disk drives. Connected to the controller for hard sectored drives, 100 kB could be written to a floppy disk. With the controller for soft sectored drives they enabled a capacity of 160 kB per diskette.
  • The H / Z-37 model also included two drives and supported a capacity of 640 kB per diskette. A controller for soft sectored drives was necessary for this.
  • The Z-47 consisted of two 8 "floppy disk drives and required its own controller.
  • In addition to an 8 "floppy disk drive, a 10 MB hard disk was built into the Z-67. This device also required its own controller.

Models

In addition to the basic model, different variations were available. It was sold as version H88 without floppy disk drives, but with a datasette interface. Heathkit sold a terminal under the name H19, which could be upgraded to an H89 with an upgrade kit . Instead of the floppy disk drives built into the H89, the H90 model had drives that could process soft-sectored floppy disks with a capacity of 640 kB and the necessary controller.

software

In addition to the operating system, Heathkit offered a text editor , an assembler and a version of its Benton Harbor BASIC interpreter for the H89 .

swell

Individual evidence

  1. ^ A b Roy A. Allan: A History of the Personal Computer: The People and the Technology , Allan Publishing 2001, ISBN 0-9689-1080-7
  2. ^ Peter Limacher: Stories of a Personal Computer . In: Zenodo . January 1, 2015, doi : 10.5281 / zenodo.46214 ( zenodo.org [accessed August 16, 2019]).
  3. ↑ Michael A. Pechura: Comparing Two Microcomputer Operating Systems , article in Communications of the ACM, March 1983 , accessed December 15, 2008
  4. ^ Look and Listen , column in Popular Science, January 1982 issue, p. 16