1980s Vintage Computers
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:
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.
There is an excellent archive of Z-100 documents and software at: http://planemo.org/retro/definitive-z-100-software-manual-repository/
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: