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== Description ==
== Description ==
The Zenith Z-89 is based on the [[Zilog Z80]] [[microprocessor]] running at 2.048 MHz, and supports the [[HDOS]] and [[CP/M]] operating systems. The US$2295 Z-89 is integrated in a [[computer terminal|terminal]]-like enclosure with a non-detachable keyboard, 12-inch monochrome [[Cathode ray tube|CRT]] with a 80x25 screen, 48 KB RAM, and a 5.25" disk drive.{{r|dahmke198008}}
The Zenith Z-89 is based on the [[Zilog Z80]] [[microprocessor]] running at 2.048 MHz, and supports the [[HDOS]] and [[CP/M]] operating systems. The US$2295 Z-89 is integrated in a [[computer terminal|terminal]]-like enclosure with a non-detachable keyboard, 12-inch monochrome [[Cathode ray tube|CRT]] with a 80x25 screen, 48 KB RAM, and a 5.25" floppy disk drive.{{r|dahmke198008}}

The keyboard is of high build quality and has an unusual number of special purpose keys: REPEAT, ESC, TAB, CAPS, CTRL, SCROLL, RESET, BREAK, BACK SPACE, LINE FEED, DELETE, REPEAT, and two with red and blue squares. There are five function keys and a numeric keypad. The video display has reverse video and block graphics are available.

The computer has a small card cage inside the cabinet next to the CRT, which accepts up to three proprietary circuit cards. Upgrade cards available for this included disk controller cards (see below), a RAM memory card accessible as a ramdrive using a special driver (above the Z80's 64 KB memory limit) and a multi-serial card providing extra RS-232 ports. The 2 MHz Z80 could be upgraded to 4 MHz.


In 1979, prior to Zenith's purchase of [[Heathkit|Heath Company]], Heathkit designed and marketed this computer in kit form as the Heath H89, assembled as the WH89, and without the floppy but with a cassette interface card as the H88. (Prior to the Zenith purchase, the Heathkit model numbers did not include the dash).
In 1979, prior to Zenith's purchase of [[Heathkit|Heath Company]], Heathkit designed and marketed this computer in kit form as the Heath H89, assembled as the WH89, and without the floppy but with a cassette interface card as the H88. (Prior to the Zenith purchase, the Heathkit model numbers did not include the dash).

Revision as of 00:22, 23 April 2022

Zenith Z-89 in Paris 2008
ManufacturerZenith Data Systems (ZDS)
TypePersonal computer
Release date1979; 45 years ago (1979)
Introductory priceKit version with 1 floppy drive: US$1800 in 1979 (circa equivalent to $7,600 in 2023)
Discontinued1985 (1985)
Operating systemHDOS, CP/M, UCSD Pascal (P-System Pascal), or MP/M
CPU2x 2.048 MHz Zilog Z80 (one for the terminal)
MemoryRAM: 16 KB – 48 KB on main board, optional 16 KB memory card (max addressable: CP/M - 64 KB, HDOS - 56 KB)
Connectivity3 serial, 1 Centronics parallel (optional), external diskette drive connector
Heathkit H88 computer[1]
Heathkit H89 aka Zenith Z-89. This unit has two half-height DD diskette drives in place of the single full-height original.

The Z-89 is a personal computer produced by Zenith Data Systems (ZDS) in the early 1980s.

Description

The Zenith Z-89 is based on the Zilog Z80 microprocessor running at 2.048 MHz, and supports the HDOS and CP/M operating systems. The US$2295 Z-89 is integrated in a terminal-like enclosure with a non-detachable keyboard, 12-inch monochrome CRT with a 80x25 screen, 48 KB RAM, and a 5.25" floppy disk drive.[2]

The keyboard is of high build quality and has an unusual number of special purpose keys: REPEAT, ESC, TAB, CAPS, CTRL, SCROLL, RESET, BREAK, BACK SPACE, LINE FEED, DELETE, REPEAT, and two with red and blue squares. There are five function keys and a numeric keypad. The video display has reverse video and block graphics are available.

The computer has a small card cage inside the cabinet next to the CRT, which accepts up to three proprietary circuit cards. Upgrade cards available for this included disk controller cards (see below), a RAM memory card accessible as a ramdrive using a special driver (above the Z80's 64 KB memory limit) and a multi-serial card providing extra RS-232 ports. The 2 MHz Z80 could be upgraded to 4 MHz.

In 1979, prior to Zenith's purchase of Heath Company, Heathkit designed and marketed this computer in kit form as the Heath H89, assembled as the WH89, and without the floppy but with a cassette interface card as the H88. (Prior to the Zenith purchase, the Heathkit model numbers did not include the dash).

Heath/Zenith also made a serial terminal, the H19/Z-19, based on the same enclosure (with a blank cover over the diskette drive cut-out) and terminal controller. The company offered an upgrade kit to convert the terminal into a full H89/Z-89 computer.

Another configuration, the Z-90, changes the floppy drive controller from the hard-sectored controller (max 100 kB) to a soft-sectored controller that supported double-sided, double density, 96 tpi drives with a capacity of 800 kB. It also came standard with 64 KB of RAM.

There were several external drive systems available for the H89/Z-89.

  • The H77/Z-77 and H87/Z-87 supports up to two additional Single-Sided, Single Density, 48 tpi 5.25" drives. When connected to the standard hard-sectored controller, it stores 100 kB per floppy. By connecting it to a soft-sectored controller, it stores 200 kB per floppy.
  • The H37/Z-37 supports up to two Double-Sided, Double Density, 96 tpi 5.25" drives and requires the soft-sectored controller. The drive has a capacity of 800 kB.
  • The Z-47 supports two 8" floppy drives and requires its own controller. It uses standard IBM 3740 floppy disks with has a capacity of 1.2 MB each.
  • The Z-67 is a 10 MB Winchester Drive plus one 8" floppy drive and also requires its own controller.
  • In France, the Heath/Zenith Data System branch connected the 10 MB removable cartridge hard disk, manufactured by Bull in Belfort

A maximum of two disk controller cards can be installed in a standard system.

Reception

Creative Computing described the Heath H89 as "the most professional looking" microcomputer available. Stating that the computer was "one of the finest" available for less than $3000, the magazine predicted that it "can have a major impact on the small computer market" if good software became available for it.[3] BYTE wrote that the H89 "has a number of unique hardware features and the same excellent software support and documentation as the original H-8 system".[2]

Summary

Display integral 12" monochrome CRT (choice of white, amber, or green), 80 × 25 characters (25th line was a special status line)
Storage 5.25" diskette drive (originally hard-sectored, 100 KB)
Operating System HDOS, CP/M, UCSD Pascal (P-System Pascal), or MP/M

References

  1. ^ Collection www.yesterpc.org
  2. ^ a b Dahmke, Mark (August 1980). "The Heath H-89 Computer". BYTE. p. 46. Retrieved 18 October 2013.
  3. ^ Heuer, Randy (April 1980). "Heathkit WH-89 (All-in-One) Computer". Creative Computing. pp. 18–21. Retrieved 2022-04-16.
Notes
  1. ^ Inflation Conversion Factors for Dollars

Reference and description

Emulators

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