Re: Minimal CP-M SBC design

>
>Subject: Re: Minimal CP-M SBC design
>   From: Dave McGuire <mcguireneurotica.com>
>   Date: Sun, 11 May 2008 08:23:13 -0400
>     To: General Discussion: On-Topic Posts Only
<cctechclassiccmp.org>
>
>Chuck Guzis wrote:
>>>    I dunno Chuck...the only reason more CP/M
systems weren't ROM- 
>>> resident back in the day was due to convention,
not technical  
>>> restrictions.  I (personally) don't think
there's anything  
>>> non-"period" about ROM-ing CP/M.
>> 
>> It's not the ROM-ing of CP/M that disturbs me, but
rather the 
>> "disklessness" of the thing.  Wasn't the
whole idea of CP/M 
>> originally to give you something to manage files on
your floppy 
>> drives?  I mean, that's what the bulk of the code
in CP/M is for--
>> heaven knows, the support for other I/O is nothing
to write home 
>> about. 
>> 
>> If one wants to enjoy a "vintage"
experience, what sense is there in 
>> being diskless?  At any rate, even something as
simple as a WD1770-
>> type controller added to the design would give that
capability with a 
>> minimum of support "glue".  
>> 
>> Alternatively, one could stay diskless and add a
sound-effects module 
>> to emulate the "chunk" and
"grrr" of a head-load and seek--and the 
>> "thunk-click" of a drive door being
opened and a floppy inserted.  
>
>   Well I wasn't talking about a diskless system...only
one in which 
>CP/M itself was in ROM.

When I mentioned it I wasn't running CP/M from rom which by
the way
takes recoding of the CCP, BDOS and BIOS to make all the
data areas
external.  What I was refering to is simply booting it from
a rom rather 
than off the system tracks.  The result of that is then ANY
formatted disk
is a boot media and makes the system a bit more bullet proof
as a 
common fault (STILL) is trying to boot a nonsystem disk or
worse having
a power glitch kill the system tracks.

When done that way CP/M is still in ram, can be overlayed,
and even 
patched.  Boot from rom also solves the chicken/egg paradox
as the
the system disk does not have to have data/programs.


>> I still don't have the hang of this
"vintage" thing yet, probably 
>> because I'm vintage myself.  Please forgive my
density...
>
>   I often suffer from the same problem.  I think very
few of us, even 
>here, actually used stuff like CP/M and PDP-11s when
they were 
>considered current technology.

Speak for yourself.  I wish that were true.  The first
version of CP/M
I ran was 1.3 When it was available and 1.4 was much better
and useful.
I had access to PDP-8 ion 1969 and PDP10 in 1971 and got my
first PDP11
in 1980(still have it too!). PDP11 stopped being current in
the 1990s 
when DEC sold the tech and licenses. Up till then you could
buy it new 
and faster (and then from mentec for years after that).


Allison

>
>         -Dave
>
>-- 
>Dave McGuire
>Port Charlotte, FL

Allison wrote:
>>> I still don't have the hang of this
"vintage" thing yet, probably 
>>> because I'm vintage myself.  Please forgive my
density...
>>   I often suffer from the same problem.  I think
very few of us, even 
>> here, actually used stuff like CP/M and PDP-11s
when they were 
>> considered current technology.
> 
> Speak for yourself.  I wish that were true.  The first
version of CP/M
> I ran was 1.3 When it was available and 1.4 was much
better and useful.
> I had access to PDP-8 ion 1969 and PDP10 in 1971 and
got my first PDP11
> in 1980(still have it too!). PDP11 stopped being
current in the 1990s 
> when DEC sold the tech and licenses. Up till then you
could buy it new 
> and faster (and then from mentec for years after
that).

   Well not *me* (or you, apparently!), but a lot of people.
 I cut my 
teeth in the early 1980s with CP/M, Atari 800, and a
PDP-11/34a.  I was 
in my early teen years at the time.  I started out in
electronics a good 
bit before that, when I was seven.

         -Dave

-- 
Dave McGuire
Port Charlotte, FL