Date: Thu, 1 Feb 2007 15:04:25 -0500
From: dave06a at dunfield.com
Subject: Re: Cromemco Unix?
>> Is there any reason of which you are aware that would prevent the
>> use of Cromix on a Z-2?
>I don't see why - All it needs (at least the Z80 version) is the ZPU,
>enough memory (a 256KZ works nicely, or a few 64KZs I think are
>OK as well) and I/O card and disk controller like 16FDC (those are
>the cards that I have) - all the standard Cromemco cards would
>work in a Z2 (I think I've had them all in my Z2 at one point or another,
>although I don't recall if I've ever booted Cromix up on it).
Since they were S-100 systems and could have pretty well any cards installed,
functionally the model doesn't really mean much except for the floppy size and the
number of floppy drives, I/O connectors and card slots.
You might have some problems with older boards. Minimum revision levels:
64KZ: Rev J
PRI: Rev E
4FDC: Rev C
16FDC: Rev E
IOP: Rev C
128K is the minimum for one user. Each additional user requires an additional
64K with a maximum of 6 users (although you could have >64 ports if you can
find room for the I/O cards and connectors). Hard disk recommended for any
AFAIK Cromix came in 3 versions with numerous revisions:
11 series is for the Z80; AFAIK latest revision was 11.27
20 series is for the 68000 (slooow, use 30 if possible)
30 series (later changed to 1xx, i.e. 153=30.53) is for 68010 and higher, although
at least the early versions will also run on the 68000.
Note that with some exceptions and depending on the hardware,
20 and 30 series will still run Z80 programs.
Also note that the 30 series has provisions to read & write PC & UNIX format
And of course the languages (BASIC, COBOL, Fortran etc.) were also updated
for the newer CPUs.
I acquired a couple of M4 9914 9-track tapes drives a while ago and
finally got around to trying to do something useful with them.
Never having used one before the first thing I did was just see if it
would mount a tape ok. The first brand new tape I tried was sucked
into the take-up reel ok and wound a few turns, then sucked all of the
way back out, then the drive tried again before giving up with a N T U
(No Take Up) error. I then tried a second brand new tape from a
different vendor and got the same results.
Then I went back into the garage and hefted (it's a workout) the
second 9914 drive into my work area and tried both tapes on the second
drive with the same result.
Then I tried manually threading a tape onto the take-up reel while the
drive was powered off and making sure that winding the take-up reel
caused the supply reel to turn, then powered on the drive and got the
same N T U error again.
I looked in the manual and it said something about the N T U error
occurring due to a lack of tach pulses. Then I looked at the tape
path for what might be the tach sensor and guessed it was probably a
metal roller near the take-up reel. I used a marker to put a dot on
the top of the reel and noticed that it wasn't rotating when the tape
was moving past it.
I tried rotating this roller by hand and I could feel detents while
rotating it and I assume it is attached to some type of rotary
encoder. Now to the point posting this here, my questions are does
anyone know if this roller/encoder needs any lubrication? If so, how?
It felt somewhat stiff when I first tried rotating it and got a
little easier to rotate the more I kept at it. And secondly, this
roller did have a thin rubber coating which had turned to goo. I
cleaned the goo off of the roller. If anyone else has seen this on a
9914 drive (I assume so, it was goo on both of mine) did they do
anything about it? Is there a good way to re-rubber this roller?
After cleaning the goo off of the tach roller and getting it to rotate
a little more freely I did see it rotate when the tape was moving past
it (wasn't sure if it would without the rubber) and now the 9914 will
mount a tape most of the time.
I have a HUGE softspot in my heart for the TRS-80 Model I, having purchased a 16k, Level I unit in December of 1978. A unit, I still own today,
I hated the keyboard too, even though I wasn't a typist, mostly because it bounced and I had to load a special keyboard de-bounce program to stop it from bouncing and getting duplicate keystrokes.
As I upgraded the unit over the years into a 48k Level II unit with several disk drives and a Percom (and later LNW) Doubler, I also upgraded the keyboard.
I was able to purchase through Tandy National Parts, the Model III style keyboard that came out on the Model I towards the end of it's run. This also had the added benefit of adding a keypad to the unit.
As to the plastic of the case, I guess in retrospect it was cheesy. But, being a kid at the time... It never bothered me. It was certainly no less cheesy than an Apple II or a VIC 20 or an Atari 400/800.
Some of the TRS-80 clones got it right I think... The LNW-80 (of which I'm a proud recent owner) and the Lobo Max-80 did a good job of making the computer less toy-like and more business like.
The PMC-80 from Dick Smith seemed even more fragile and toy-like, however.
As to the hardware design being none too exciting. I wouldn't know, not being a hardware guy at that level. Though, we had used the Dennis Bathory Kitsz book to hop up my Model I with LowerCase, Internal Speaker, Internal Alpha-Compatible Joystick Interface, High Speed (turbo) mod with tri-color LED to indicate Low, High, and Auto (High on most things, low on Cassette and Floppy access). Also, external reset button and composite video for an amber monitor.
Computers were fun in those days. I remember applying the zaps from 80-Microcomputing to a copy of Newdos 2.1 to speed up the disk stepping and amazing the salesman at my local Radio Shack at how much faster I could make their Model I boot up.
Those were the days...
In the late 70's and early 80's I think the TRS-80 outsold the Apple II's. Mainly because there were more outlets selling TRS-80's (Radio Shack and Tandy Stores) than there were selling Apple II Computers.
But, I can say as a former New Yorker, and a Computer Consultant at that time, that I saw MANY more Apple II's running VisiCalc than I did TRS-80's.
The Apple II overtook the TRS-80 and by 1984 or so, the Model I/III/IV was pretty well dead and dying as a platform, while the Apple IIe and IIgs had plenty of life left in them.
I loved my TRS-80, but I also lusted after an Apple IIe chock full of Applied Engineering goodies...
I never did get one of those, though I have several IIgs machines and a IIc.
Just to clarify:
1. These are 40pin DIP Plastic packaged Chips
2. These are CPU chips, not eproms
3. These are not free. We have to pay someone for them. I am doing someone a favor and offering them to people who would most appreciate them.
These are the same chips used on the COSMAC ELF.
If you are repairing an old unit, or building one of the new clones... You might want some of these.
We only have a limited amount of chips. Once these are gone, I can't get any more.
Brad Parker <brad at heeltoe.com> wrote:
> ... has anyone written an emulator for a VS60?
> would it be hard?
Doug Gwyn took my crappy VT11 simulation and extended it to within
episilon of passing all the VS60 diagnostics.
For a start see:
Which shows screen shots of PDP-1 "munching squares" and "spacewar"
on a simulated "Type 30" display, one of PDP-11 Lunar Lander...
Sources are available thru my CVS server, tho I can't be sure I have
checked in Doug's very latest (the vt11.c file in CVS is dated October 2005).
We never managed to get it integrated into SIMH distributions, and I
don't know off hand the last version of SIMH it did build with. The
"display.tar.gz" on the web page is from October 2003(!), and I see
there is a source kit named at
http://www.ultimate.com/phil/xy/kit2.zip from February 2004.
I did a rather "basic" (or "crude" to be less generous) graphics
adaptation layer for X11 (polled) and Win32 (starts a seperate thread
for message handling). John Dundas contributed an implementation of
it for "Carbon" under OSX.
There have been several other attempts to add graphics of various
sorts to SIMH, including VAXstation style raster display support.
John (Dundas) went on to build do PDP-11 front pannel blinklights und
switches for SIMH, looks like it's available at:
Which says it includes Doug's and my work (in V0.9 or later).
But, back to the original topic, I think SUDS needs a PDP-10
(TOPS-20?) system behind it to do the real work.
I used to pass the PDP-10 hardware design lab on the way to the
Cafeteria at MR-1 (DEC Marlboro(ugh) building one, before the great
three letterization that made it into MRO-1). I loved the "rose"
program I saw sometimes on the displays, but I don't remember what it
looked like anymore... Anyone have the code, or remember what it did?
> Umm, and how rare are VS60s these days?
Essentially unobtainium. They were expensive and rare 25 years ago.
You'd have better luck finding a VT11 or GT40. At least I KNOW people
who have those. I've never known anyone in the 30+ years of dealing
with DEC stuff who had a VS60.
I've been chasing a copy of SUDS for a while. It existed at Stanford,
MIT, and DEC. XKL still uses it.
The DEC version will probably be somewhere on the DEC LCG tapes. There
are bits of it on the ITS tapes that have been released. I'm sure it's
on the ones that haven't.
> I have the Z-80 Cromix running on one of my System-3's, and yes
> I have install disk images up on my site.
I got to meet the original author a few weeks ago. It started out
as a personal project of his, and morphed into a product.
Cleaning out more junk; found some HP boards, probably
>from a tape drive; anybody want 'em for parts? Condition
unknown, one marked defective:
07970-62140 series 1144
07970-60020 series 1047