[sebhc] h17 and h8d disk images

Barry Watzman Watzman at neo.rr.com
Wed Sep 1 20:54:42 CDT 2004

4200 Hex wasn't chosen for any of those reasons.  It was chosen because it
was already in use on the TRS-80, which had 16k of ROM at zero for Microsoft
Basic (in ROM).  It was bad enough that there had to be a "non-standard"
CP/M system, but Heath [meaning, at the time, me] and Lifeboat were not
going to have multiple non-standard CP/M's it was tough enough to get
Microsoft, Micropro, Digital Research, Sorcim, etc. to create one
non-standard object code version of everything let alone two (or more) for
different vendors.

-----Original Message-----
From: sebhc at sebhc.org [mailto:sebhc at sebhc.org] On Behalf Of Dwight K. Elvey
Sent: Wednesday, September 01, 2004 9:43 PM
To: sebhc at sebhc.org
Subject: RE: [sebhc] h17 and h8d disk images

 H17 puts RAM variables just above 2000H. The boot code
loads the boot sector at 2280H. I would think that a
Heath compatable CP/M would just have to keep above
2300H. ( 430000 Heath split octal )

>From: "Barry Watzman" <Watzman at neo.rr.com>
>I think that the RAM base was much higher even than 2000H, but yes, such a
>version of CP/M did exist.  Getting a copy will be very, very hard, because
>it fell into extreme disfavor after the version came out that supported a
>"normal" CP/M memory configuration.
>[In case anyone is wondering, I have almost no H8/H89 software at all, I
>don't even have a copy of the software that I myself wrote.]
>-----Original Message-----
>From: sebhc at sebhc.org [mailto:sebhc at sebhc.org] On Behalf Of Dave Dunfield
>Sent: Wednesday, September 01, 2004 8:39 PM
>To: sebhc at sebhc.org
>Subject: RE: [sebhc] h17 and h8d disk images
>At 18:53 01/09/2004 -0400, you wrote:
>>I agree -- save the version with the header, and use the conversion
>>to convert to the version without the header, if necessary.
>>There were two versions of CP/M used on the H8.  The "Lifeboat" version
>>"org'd" at 4200H, I think (my recollection is fuzzy), but the real Heath
>>version was standard "org 0" and required RAM at zero.
>So is there a version of CP/M which will boot on a system with the H17
>controller, the standard H5 I/O card, and RAM from $2000 to top of memory
>(IE: the configuration of my emulator) - if so, where can I get an image
>of it, because I would love to try it out.
>dave04a (at)    Dave Dunfield
>dunfield (dot)  Firmware development services & tools: www.dunfield.com
>com             Vintage computing equipment collector.
>                http://www.parse.com/~ddunfield/museum/index.html
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