14 Oct
2007
14 Oct
'07
11:13 a.m.
On Sunday 14 October 2007 03:01, M H Stein wrote:
The main thing I wanted to do in terms of making a cable was to extend the
power connection for the installed drive so I could get it far enough out of
the box to work on it. Do you (or anybody else in here) know what that odd
connector is they're using to supply power to the drive?
That sort of hacking is just a bit beyond where I've gotten to with that
stuff...
Got plenty of 7812s on hand here, and adding additional sizes sounds like a
worthwhile project, if I can get the system to support 'em. Power wiring is
probably the single point where I'm getting hung up there.
Well, hard sector disks might still be a problem...
I've actually encountered those so seldom that this isn't likely to be a
problem for me.
Not relevant or supported in single-user CDOS (which used ordinary TUART
4-port serial and PRI 2-port parallel cards), but running a multi-user
sort-of-UNIX on a 4MHz Z80 wasn't exactly blindingly fast, especially on
the slow hard disks of the day. If the main CPU also had to directly
service all those UARTS it probably would grind to a halt so they handled
serial I/O with coprocessors (IOP & Octart), which later could also run Z80
user software in between I/O requests when there wasn't a Z80 on the main
processor board any longer.
Hmm.
You'd need it for 5.25 drives for sure, but many 3.5" drives actually only
require 5V which you already have for the 8" drive.
True.
I've seen some S-100 stuff around from time to time, but am not particularly
into investing a lot of money into this setup. Perhaps I'll acquire some
stuff to plug in there eventually.
Indeed...
Can't help any with the Bigboard, alas.
The Bigboard I was essentially the same as the Xerox 820-1, and I saw both
the I and II versions advertised in Micro-Cornucopia magazine over quite a
span of time. It's still surprising to me that there's so little information
out there on those.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
Date: Fri, 12 Oct 2007 21:00:18 -0400
From: "Roy J. Tellason" <rtellason at verizon.net>
Subject: Re: Extracting CDOS and CP/M) files
<much snippage>
It _is_ a System 3.
<snip>
That's more than I've got in there.
It's a ZPU, 64KB ram card, I
*think* that 64FDC, and an I/O card, not real sure but I think maybe
it's the PRI...
Your basic single-user CDOS system, although I suspect that's a 16FDC.
I assume it's a System 3, or perhaps a Z-2? Either way, lots of room in
there for expansion ;-) No CDOS handy,
I'm not even sure what I got for disks with that box,
though I did get some, the problem with the drive having done some
physical damage to the one that was in it. Somewhere around here I have
a box of 8" floppies, but that would include what came with this system
and also what came with the Imsai, at least, plus probably some stuff
that folks have sent my way over the years.
Dave D has various images on his excellent site - also see below. If you're
having trouble with the 8" drive(s) and haven't gotten around to making
the cable for a 3 1/2" substitute, add a 7812 or use an old PC supply and
temporarily hook up a 5 1/4" drive; the FDC handles both. I'm not
sure if I even have CP/M specific to that box.
Several people have configured CP/M for the Cromemco configuration; Barry
Watzman for one, if I'm not mistaken. Mostly I was
looking for what sort of hardware capabilities would be
needed...
You've got the basic hardware except for a 7812 or equivalent for the 5.25
(and 3.5" if 12V - see below) drives; the rest is software ;-) <snip>
If/when you do, it's certainly out there. Several sites have extensive
collections of Cromemco software and manuals; one of the most complete is
Marcus' site:
http://maben.homeip.net/static/S100/cromemco
(Also see Herb Johnson's & Howard Harte's sites).
Noted.
Any
version of Cromix (Cromemco's early Z80 and 68000 pseudo-UNIX) can
read/write any version of CDOS or Cromix disk (floppies, that is; hard
disks are a different story).
I'd love to get some info on that software, particularly if I can ever
get my hands on a DPU card to stick in there. To run Z80 Cromix, all you'd need is another 64K;
to run 68K Cromix/+
you'd need at least a 68000 DPU and 256K would be nice.
Yes.
One of the things I can recall from reading what docs I have on hand here is
that they used several bus lines to select individual ram banks, rather than
using them as address lines, which puts an upper limit of how far you can go
in that regard. I wish they'd gone the address bits route, and have had
idle thoughts about how difficult it might be to modify things.
<snip>
Anything else would indeed require some custom
programming; the FDC
controller cards were reasonably well documented.
That's mostly what I was looking for, if the common FDC chips back in
those days were likely to be sufficient to handle a wide variety of
"stuff" out there. If the main CPU was a 680x0 instead of a Z80 then Z80
& CP/M software
was run either on a dual (Z80/68000) DPU card or, if there was only a
680x0 CPU then it was run on the Z80 on an I/O card such as the IOP I/O
processor or the Octart 8-port RS-232 card, if available.
I saw the sheet on the IOP in my book just now, but don't know about that
other one. Why would they stick a processor on an 8-port serial card? The IOP is only the I/O *processor* BTW; there can be
up to 4 installed,
and each can control up to 4 Quadart 4-port serial cards for a maximum of
16 ports; that'd keep a single Z80 so busy it wouldn't have much time to
actually run those users' programs ;-). The Octart is a coprocessor and 8
ports combined, and a system could have up to 4 for a total of 32 ports;
although in practice you wouldn't have that many users you could have I/O
devices on all of those ports (I have in fact had Cromemco systems
installed with more than 32 terminals, although they were not all unique
"users").
There is definitely some appeal in the idea of having lots of I/O, but
unfortunately the closest I've come to that is that TeleVideo 816 I have,
which only seems to be set to talk to other TeleVideo gear, of which I have
none...
Though I *do* have an ISA card around that's supposed to hook into that stuff.
Their first hard disks were 11MB 8" IMI drives
using a WDI controller;
they were superseded by 5 & 20 MB 5" IMI drives requiring a WDI-II. Then
came MFM disks using an STDC controller and SMD drives & controller, and
finally ESDI and SCSI drives using the ESDC controller.
Rigging up some sort of mounting hardware and finding 12V power for some
of the 3.5" HDs I have kicking around here should be an interesting
exercise. :-) I have nothing
around for a controller, but given the choice I'd rather
go with SCSI if possible.
SCSI wasn't supported until pretty late in the game and you'd need fairly
late versions of cards & OS; definitely not an option with your setup. The floppy controller also supported the small tape
drives while the
larger tapes required the ESDC controller, and there was also a
controller and OS support for 9-track mag tape.
Hmm.