website/content/museum/heathkit-zenith-h-89.md

---
title: HEATHKIT / ZENITH H-89
categories:
- Computers
types:
- Professional Computer
origins:
- U.S.A.
years:
- '1979'
cpus:
- Zilog Z80
params:
  name: H-89
  image: /media/museum/photos/h89.jpg
  company: /companies/heathkit-zenith
  company_name: HEATHKIT / ZENITH
  specs:
  - label: NAME
    value: H-89
  - label: MANUFACTURER
    value: Heathkit / Zenith
  - label: TYPE
    value: Professional Computer
  - label: ORIGIN
    value: U.S.A.
  - label: YEAR
    value: '1979'
  - label: END OF PRODUCTION
    value: '1983'
  - label: BUILT IN LANGUAGE
    value: None
  - label: KEYBOARD
    value: Full stroke keyboard with numeric keypad
  - label: CPU
    value: Zilog Z80
  - label: SPEED
    value: 2.048 MHz
  - label: RAM
    value: From 16 KB up to 64 KB
  - label: ROM
    value: Custom bootup & monitor
  - label: TEXT MODES
    value: 80 chars. x 24 lines ( + one independant line)
  - label: GRAPHIC MODES
    value: No graphics mode. 33 graphic characters
  - label: COLORS
    value: Monochrome green phosphore display
  - label: SOUND
    value: Beep - HUG magazine had a article on how to use one of the serial ports as a crude
  - label: I/O PORTS
    value: RS232 (two, up to six), Centronics, IEEE 488
  - label: BUILT IN MEDIA
    value: 90 KB floppy drive
  - label: OS
    value: HDOS, CP/M, MP/M
  - label: POWER SUPPLY
    value: Built-in power supply unit
  - label: PRICE
    value: $1,800 as kit in 1979 w/ 1 floppy drive
  tabs:
  - photos
  - adverts
  - hardware
  - software
  forum_thread: 147
  photos:
  - title: H89 AND H77 FD UNIT
    subtitle: ''
    text: |-
      Complete Heathkit H89 system with the H77 F.D. unit and the Heathkit H-14 serial printer.

      The H77 unit had a storage capacity of 150 KB x 2. This configuration allowed a system disk to be installed in the H89 integrated floppy and data disks in the external unit drives.
    image: /media/museum/photos/heathkit_h89_h89-h77_1.jpg
  - title: THE PERFORATED RUBBON READER
    subtitle: ''
    text: it can read 50 characters / second and write 10 characters / seconds
    image: /media/museum/photos/rub_h11.jpg
  - title: H/Z-67 HARD DISK UNIT
    subtitle: ''
    text: It contained one 10MB 8" winchester drive and one 8" floppy drive
    image: /media/museum/photos/p_z891.jpg
  - title: Z-47 (8'' FDD)
    subtitle: ''
    text: ''
    image: /media/museum/photos/p_z892.jpg
  - title: THE H19 / Z19 TERMINAL
    subtitle: ''
    text: This terminal is simply a H89 system without the logic CPU board and disk storage. It was called Heathkit H19 in kit form and Zenith Z19 in assembled form. It could be connected to any system via a serial connection.
    image: /media/museum/photos/heathkit_h19_terminal_1.jpg
  - title: UNOPENED KIT
    subtitle: ''
    text: When a customer ordered a H89 in kit version, he received five boxes. The 5th. one holded the case, floppy disc drive and manuals
    image: /media/museum/photos/heathkit_h89_kitunopened_4.jpg
  - title: DUST COVER
    subtitle: ''
    text: ''
    image: /media/museum/photos/heathkit_h89_dustcover_1.jpg
  adverts:
  - title: 1979 RANGE ADVERT
    subtitle: ''
    text: |-
      Advert shows:

      \- the **WH89** computer ($2295)\
      \- the **WH11A** 16-bit computer, DEC PDP 11/03 compatible ($1895)\
      \- the **WH19** video terminal ($995)\
      \- the **WH26** dual floppy disc system ($2595)\
      \- the **WH14** serial printer ($895)

      To note: in 1979, the company name was **Heath Schlumberger data systems.**
    image: /media/museum/pubs/heathkit_h89_pub_2.jpg
  - title: 1980 RANGE ADVERT
    subtitle: ''
    text: |-
      Advert said:

      Choose from three computer systems:\
      The H-89 All-In-One Computer gives you everything in one compact, convenient unit.\
      The flexible H8 gives you the freedom to combine memory and interfacing for exactly the system you require.\
      And the powerful H11A gives you 16-bit power for your most complex programs.\
      The Heathkit line includes video terminals, matrix and letter quality printers, and accessories. You'll even find award-winning self-instruction packages to teach yourself programming in Basic or Assembly.
    image: /media/museum/pubs/heathkit_h89_pub_1.jpg
  - title: 1982 HEATHKIT CENTERS
    subtitle: ''
    text: ''
    image: /media/museum/pubs/heathkit_h89_pub_3.jpg
  - title: 'HEATHKIT CENTERS #2'
    subtitle: ''
    text: ''
    image: /media/museum/pubs/heathkit_h89_pub_4.jpg
  - title: HEATH 19 TERMINAL (1982)
    subtitle: ''
    text: |-
      $595 was the price in kit form, F.O.B. Benton Harbor...\
      The assembled version, called Zenith Z-19, costed $895. An expensive price, not compatible with a home computer budget.
    image: /media/museum/pubs/heathkit_h19_pub_1.jpg
  - title: FRENCH ADVERT (JAN. 1982)
    subtitle: ''
    text: '"Adopt a little gifted"'
    image: /media/museum/pubs/zenith-heathkit_h89_french-pub_1.jpg
  hardware:
  - title: EXTERNAL DRIVES
    subtitle: ''
    text: Here is a H89 with Hard and Soft Sectors floppy-drives, along with hard-disk drive at the bottom....
    image: /media/museum/hardware/heathkit_h89_complete_1.jpg
  - title: FLOPPY AND HARD-DRIVES
    subtitle: ''
    text: Hard and Soft Sectors floppy-drives, along with hard-disk drive.
    image: /media/museum/hardware/heathkit_h89_drives_1.jpg
  - title: H77 FD UNIT
    subtitle: ''
    text: 2 x 150 KB 5.25" drives unit with its dust cover.
    image: /media/museum/hardware/heathkit_h89_h77fdunit_1.jpg
  screenshots:
  - title: HDOS MANUAL
    subtitle: ''
    text: Floppy discs operating system manual
    image: /media/museum/software/heathkit_h89_hdosmanual_1.jpg
  oc_id: 135
  source:
    url: https://web.archive.org/web/20230331021329/http://www.old-computers.com/museum/computer.asp?c=135
    date: '2023-03-31'
---

The H-89 was sold under the two names: **Heathkit H-89** and **Zenith Data Systems Z-89**. The H-89 was sold in kit form, the Z-89 came assembled.

It originally came with 16 KB of memory, later versions provided up to 48KB on the main CPU board (in groups of 1 KB chips). Zenith and Heathkit offered a 16 KB expansion card ($120) for a total of 64 KB when using CP/M.

The system was identical to the **H-19** video terminal but had an additional CPU board between the CRT and the terminal board. (Really identical because Heath offered upgrade kits to convert an H-19 to an H-88/H-89 computer).

It used hard sectored disks with a built-in card controller. Under either H-DOS or CP/M, disk capacity was of 90 KB. Another model the **H-88** was identical to the H-89, but did not include the floppy drive or controller. It had a cassette port.

A couple of years later, the **H/Z-37** soft sectored controller and ROMS came out, then was replaced with a double 5.25" floppy disk drive called **H/Z-87** (102 KB, 250 ms). A double 8" floppy disk drive called **H/Z-47** (1 Mb each) and a hard disk called **H/Z-67**, it contained one 10MB 8" winchester drive and one 8" floppy drive (like the one in the H/Z-47).

It ran under **HDOS** or **CP/M** (the operating system used 16 KB of RAM).\
HDOS was originally written for the [H-8](/museum/heathkit-h8/), it ran without modification on the '89. This was a single-user OS written by J. Gordon Letwin for Heath. It included a Basic interpreter and assembler.\
For CP/M, H/Z wrote a custom BIOS in assembler that the new user could further customize for his specific hardware and assemble right on the machine.\
A version of **MP/M** was also available for the system.

A lot of extension boards were available for this computer including 64 KB memory boards, hard-disk controller cards, 3-port serial I/O board, H19 terminal board, etc.\
A third party small upgrade card was also offered which doubled the processor speed to 4 Mhz.

An assembler/debugger was given with the DOS. A paper tape reader was available as well. Microsoft has adapted its various programming languages (Basic, Fortran, Cobol) for this computer. Borland also offered a version of Turbo Pascal that worked great with the CP/M.

**Dennis** reports:\
The base H-89 had no graphic modes, just 33 graphic characters. At least two different add-on boards were created that gave the H-89 bitmapped graphics capabilities, but I'm pretty sure they both required hardware modifications to tie them in to the terminal board - this was not a simple plug-in expansion card