1980s Vintage Computers
Zenith Z-100
The Zenith Z-100 (also sold as the Heath Z-100 by Heathkit) was an innovative design which combined an 8-bit Z80 processor (to run CP/M) with a 16-bit 8088 processor (to run Zenith's version of MS-DOS, know as ZDOS). It has a large motherboard and can be expanded due to having four S-100 slots. There were two models, mine (the Z-120, now sold) features:
- A single box design with built in screen, keyboard and disk drives.
- Built in green screen, with a mix of 80 column text or 640x200 graphics (colour output on CGA socket).
- Z-80 8-bit processor running at 4 MHz.
- 8088 16-bit processor running at 5 Mhz.
- 192KB of user RAM, plus 48KB of video RAM.
- Built in serial and parallel ports.
- Twin 360 KB floppy drives (uses soft-sector floppies), in double density double sided mode.
- Basic diagnostics on ROM.
Zenith also made a model without a display called the Z-110.
This computer was introduced in around 1982. It was quite popular in the US, but in the UK it was not very popular.
Here are some photos of my machine. Note the paper clips used to unclip the case!
Links
There is an excellent archive of Z-100 documents and software at: https://planemo.org/z-100/
There was a site with Z-100 boot disks at: http://www.computernostalgie.site90.net/ZenithZ100 but this site appears not to be maintained, it was copied to the Internet Archive. The disk images don't appear to be copied, I had downloaded some of them and have uploaded these to Dropbox.
Zenith Z-100 pages can be found at:
old-computers,com (note site no longer working)
This page was last revised on: 16/11/14