Sometimes brevity is the soul of confusion....
At 20:42 -0500 4/18/07, Allison wrote:
>Not true as the rainbow also ran CP/M-80/88 as it was a dual CPU (has a z80).
At 20:42 -0500 4/18/07, Pat wrote:
>I'd imagine that Mark meant that the amount of memory (832k) was
>irrelevant to CP/M-80.
At 20:42 -0500 4/18/07, Chris wrote:
> Could it access more then 64k under CP/M-80? Don't
>you mean CP/M-86? Not to nit pick...
> I don't know about specific Rainbow revisions, but I
>was under the impression the 'bow could go up to 896k.
>Maybe I'm thinking of the Tandy 2000 via an 3rd party upgrade.
Pat's right, I meant the 8080/Z-80 form of CP/M would (I think) not
access anything above 64k for the Z-80. I remember thinking it would
be a neat hack to make the other 768k into a RAMdisk for CP/M on the
Z-80, using the 8088 to serve it.
Allison's right too, CP/M-80/86 would access the full 832k (or 896k
in a B model) for the 8088 processor to run (and I think that's the
original OS supplied with the machine, though MS-DOS was also
available).
Rainbow PC-100A could not be (I know, and I don't mean that as a
challenge - I'm just talking about factory-supplied options...)
expanded beyond 832k RAM, and the 8087 coprocessor card mine uses was
one of the few ways to expand that far.
PC-100B and PC-100+ (The latter with a hard drive and controller and
a different badge, but otherwise identical to a B) both could be
expanded up to 896k RAM.
In any case, thanks for the clarification(s)!
--
- Mark, 210-379-4635
-----------------------------------------------------------------------
Large Asteroids headed toward planets
inhabited by beings that don't have
technology adequate to stop them:
Think of it as Evolution in Fast-Forward.
Rumor has it that Ethan Dicks may have mentioned these words:
>On 4/26/07, Jules Richardson <julesrichardsonuk at yahoo.co.uk> wrote:
>
>>[1] I don't buy new stuff, not for PCs - not when the price drops so much for
>>"previous generation". Unfortunately SCSI drives of 36GB and up don't seem to
>>be readily available.
Well, a) this might be "wrong side of the pond" for you, and b) I'm not
sure what you consider "cheap" but this place only has 633 in stock and
ready to sell:
http://www.pacificgeek.com/product.asp?ID=39962&C=202&S=1005
Hitachi 36.9GB Ultra 320 SCSI 10000RPM HDD --- $56.99 each.
IMHO, not a *horrible* price, and with some froogling (oops, I guess that's
gone now) you might be able to find 'em cheaper...
>I got a few in 2003, cheap, but I'm not seeing server drives as
>abundantly as I used to. The ones behind me are loaded with "SAS"
>(Serial-attached-SCSI, AFAIK), so perhaps the days of SCA-connector
>UltraWIDE SCSI drives are waning at last.
Doubtful... at least not just yet, IMHO. I'd think there's still a lot of
installations with 68/80 pin SCSI hardware - but with supply-n-demand, I
doubt new drives will get cheaper - we're prolly at the point where they're
going to start getting more expensive than the SAS & whatnot.
Laterz,
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger | Anarchy doesn't scale well. -- Me
zmerch at 30below.com. |
SysAdmin, Iceberg Computers
>
>Subject: Re: Junkbox parts...
> From: "Alexandre Souza" <alexandre-listas at e-secure.com.br>
> Date: Fri, 27 Apr 2007 00:14:20 -0300
> To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org>
>
>> I've seen that and personally I'd like to isolate the system from the
>> nasty scancode output from the keyboard so that the result looks like
>> simple ASCII 7bit. I'd have to reprogram the 8742s to do that as the
>> extracted parts only serve as a serial IO and buffer.
>
> Although this is a cannon to kill a microbe, it can be done.
>www.mcselec.com has a nice basic compiler with incluided PS2 keyboard
>decoding. Write a small basic program to translate the scancodes to
>whatever-you-want and you're in!
Not only the heavyest solution I've seen to date also one of the
more costly. The "nice" basic compiler is 79Euros.
Allison
I've been cursing my way through a load of DC300XL/DC600A carts
written a bit over 20 years ago. They're mixed "Scotch" brand (blue
logo) and "3M" (red logo).
The "Scotch" ones have been an unmitigated nightmare. Binder bleed
visible between wraps on each reel (white gloppy deposits), flaking
of the binder (the tension band has great chunks of oxide firmly
laminated to it). Really awful news and prety much a total loss.
The "3M" brand are largely recoverable, with a few missing block
errors.
Does this match everyone else's experience with these two brands?
Cheers,
Chuck
>
>Subject: Re: Junkbox parts...
> From: Holger Veit <holger.veit at iais.fraunhofer.de>
> Date: Tue, 24 Apr 2007 09:37:48 +0200
> To: General Discussion: On-Topic Posts Only <cctech at classiccmp.org>
>
>Allison schrieb:
>> The question on junkbox z80 systems made me remember that
>> old 386 and 486 system besides providing a raft of 32kx8 SRAMS
>> also had a keyboard interface chip..
>>
>> I have a few salvaged 8742(smae as 8242) from PC hardware
>> of the AT class 80386-486 level.
>>
>> Without resorting to eraseing the Eproms (8742) and reprogramming
>> them I've wondered if..
>>
>> Can these parts (PC AT keyboard interface) can they be used for
>> small system as a interface from AT or PS2 keyboard to a 8bit micro.
>> Right off I suspect yes. However is there any information on how
>> to "talk" software wise to them as to what kind of results and
>> commands they take?
>>
>>
>See http://www.arne.si/~mauricio/kbdfaq.html for abundant information on
>the keyboard,
>and programming the controller. Basically, you connect it to a z80 the
>same way as it is done
>in the PeeCee - wire it to i/o port 60/64h and use the same logic to
>program raw commands.
>Normally, in homwbrew systems, people tend not to use a 8042 pulled from
>a scrap board but talk
>to the keyboard directly, through the serial protocol described above.
>The keyboard itself typically
>contained some 8048 controller to scan the kbd matrix.
I've seen that and personally I'd like to isolate the system from the
nasty scancode output from the keyboard so that the result looks like
simple ASCII 7bit. I'd have to reprogram the 8742s to do that as the
extracted parts only serve as a serial IO and buffer.
>I don't have the exact circuitry for the 8042 UPI at hand right now, but
>the schematic can be
>found in the IBM AT Technical Reference Manual.
I have more than enough info on the 8742 itself, I use them for other
applications. The PC AT circuit is trivial and I have that as well.
Allison
All:
Does anyone have a consistent source for dual 5.25? half-height external
floppy drive enclosures? I?m looking for an external case for my 68k SBC.
Thanks in advance for any pointers.
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.altair32.comhttp://highgate.comm.sfu.ca/~rcini/classiccmp
>
>Subject: Re: Hand-rolling a CP/M machine
> From: woodelf <bfranchuk at jetnet.ab.ca>
> Date: Wed, 25 Apr 2007 22:22:11 -0600
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
>
>Allison wrote:
>
>> You have to be kidding me. All you need is a 2764 and a programmer.
>> It's a ROM and the pattern is in the manual, what could be easier?
>> Actually if someone were building I'd suggest using a 2764 over the
>> part used on the VDM1 as that was a two or three voltage part and
>> 27C64(or even a 27C256) is common as flies plus lower power.
>
>Well if I still had the manual let alone the the VDM ... :(
>
Manual is on line I think at both Dave and bitsavers.
Allison
>
>Subject: Re: Hand-rolling a CP/M machine
> From: woodelf <bfranchuk at jetnet.ab.ca>
> Date: Thu, 26 Apr 2007 16:20:17 -0600
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
>
>Allison wrote:
>
>>>> You have to be kidding me. All you need is a 2764 and a programmer.
>>>> It's a ROM and the pattern is in the manual, what could be easier?
>>>> Actually if someone were building I'd suggest using a 2764 over the
>>>> part used on the VDM1 as that was a two or three voltage part and
>>>> 27C64(or even a 27C256) is common as flies plus lower power.
>>> Well if I still had the manual let alone the the VDM ... :(
>>>
>>
>> Manual is on line I think at both Dave and bitsavers.
>
>Off hand I don't see it at bitsavers.
>
the stufffs out here. Here's Dave's site and page.
http://www.classiccmp.org/dunfield/s100c/index.htm
Scroll down the page to Processor tech it's a 6mb PDF but that
manual has sources for the Driver program, listing of the pattern
for the character rom and operating theory.
Else where on the same page are several other S100 boards that do
video some are 64x16 and at least one is 80x24.
Dave happens to have a well organized site for old computer history.
Allison
