Susan M Johnson wrote:
>
> On Thu, 1 May 1997, Bill Whitson wrote:
>
> > Hi all.
> >
> > After getting your numerous recommendations on the last
> > version ;) I updated the List of Classic Computers. It
> > now includes 83 more machines and notes as to CPU, base
> > RAM, Primary OS,
> >
> >
> > ==================================================================
> > MANUFACTURER
> > MODEL CPU RAM OS TYPE YR
> > ==================================================================
> > Zenith Data Systems-----------------------------------------------
> > Z-89 Z80 48K ?? MICRO 79
> > Z-90 Z80 64K ?? MICRO 81
> > Z-100 8088 w/8085 192K ?? MICRO 82
>
> To add to his list, fill in blanks:
>
> Z-89 HDOS/CP/M-80
> Z-90 HDOS/CP/M-80
> Z-100 192K/768K CP/M & Z-DOS
>
> Heath Corporation-------------------------------------------------
-->> H-8 8080 or Z-80 48Kb HDOS/CP/M-80
<<<<<<<<----------
> H-89 Z80 48K HDOS/CP/M-80 Micro 79
> H-90 (?)
> H-100 8088 w/8085 192K/ CP/M & Z-DOS Micro 81
> 768K
>
> The Heath Corp. computers (Heathkit) actually preceded the Zenith
> computers, although they are basically the same computer: the Heath
> version is the kit form, and the Zenith version is the factory assembled
> form. Heath originally designed them, then Zenith acquired Heath. I
> think the H/Z-100 was the first they worked together on.
>
No... Zenith designed 110 and 120 series but Heath designed into kit
forms
with assembly manuals. Barry Waltman, engineer for Heath Company
resigned
and fed up with Zenith. He was master designed for H-8 and H-89 series
> The Heath/Zenith H/Z-100 is a dual-operating system computer, running
> both CP/M and Z-DOS (Zenith DOS), then later Zenith-modified MS-DOS. The
> CP/M runs on the 8085, and the MS-DOS/Z-DOS boots up on the 8085, then
> switches to running on the 8088.
Correct!!!
Other OS available were CCP/M, CP/M-86,
> MMP/M (very brief),
No... there was as follows: CP/M-85, CP/M-86, Concurrent CP/M-86, ZDOS
then changed to MS-DOS (with Zenith routines).
and I think that there was also a version of Xenix
Unforuntately, there was never using Xenix those days!!!
> available, although I'm not positive about that. Seems to me it was also
> possible to get the Pick OS, but again, my memory is hazy as to that. At
> any rate, neither was the main OS if they were available.
>
> Once the 41256 RAM chip became available, the H/Z-100 had a maximum of
> motherboard RAM of 768K (became available from Heath/Zenith in 1985, I
> think). It's capable of addressing 16 Meg if someone wanted to put it in,
> although they would have to write their own software to manage it.
Correct!!!
>
> Currently, the H/Z-100 can run 8", 5 1/4" (40 & 96 tpi), and 3 1/2" (96
> & 135 tpi) floppy disk drives; MFM hard drives (also RLL, although not
> common), tape drives, and SCSI drives. CD-ROM drives are also possible.
>
During days of H/Z-110 and 120... there are only two floppy disk drives,
5.25" and 8". The 8" system was short lived. There was never using
3.5"
but some people successful attempted this way when H/Z-100 were no
longer
in market. They have to write a special software included BIOS to work
with 3.5" drive. SCSI system on H/Z-110 or 120 was very rarely. Those
days it was called SASI. There was never using tape drive or CD-ROM
drives
because H/Z-110 or 120 never use with IDE or EIDE. But it can use with
SCSI based interfaced.
> It was designed to run both 8- and 16-bit software, so people who had a
> big investment in 8-bit software running under CP/M would be more willing
> to buy a new computer. That dual OS design sold the military on the
> computer, and Zenith made a bundle on military contracts for it.
>
It was very sad part of H/Z-110 or 120... people use 8-bit software were
almost never existence because of 8085. During early days when Zenith
developed new 110 or 120. They abandoned idea to use 8086 and Z-80.
They decided against it because of cost and difficult to interface.
Barry Watzman disagreed and quitted. Zenith people tend to think for
themselves and very selfish also greedy. Military gave a big contracted
but later they were not happy with Zenith and decided no longer
business.
> Original operating speed was 5 Mhz; Heath/Zenith later upped that to 8
> MHz. A common modification allows it to run at either 8 or 10 MHz.
> Someone has also managed to get it running at 33 MHz.
>
FCC tracer will love to catch a person who run at 33 MHz. The board was
not design to go that higher. Perhaps he must put a lot of leads to
block
excessive RF and EMI.
> However, it is not PC-compatible due to the S-100 buss design and the
> video. You can run a great deal of PC software on it, although
> the code may need patching in order to do so.
>
There were two famous hardware-based additional will allow to run
PC-compatible software. They were GEMINI and EasyPC. I am using
GEMINI but of course I cannot run Windows 95 :-(
> Hope this adds to your computer list & provides interesting information.
>
> Susan
Received on Fri May 02 1997 - 19:36:59 BST
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