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Cromemco Z2-D N00bish Questions

Kudzu Kid

Kudzu Kid

Member
Joined
Dec 8, 2022
Messages
12
Location
Metropolis of Tulsa
A few questions: I’m pondering hunting down a Cromemco Z2-D (the cheaper $ the better, I'm old, fixed income, massive medical bills from heart surgery and cancer, but I'm still kickin', LOL, etc.). It’s only been ~48 years since I last used one. So I have a few questions. Yes, I confess, I could probably Google some of this, read numerous sites / pages with varying degrees of relevance. Or I could spare myself that fire walk and hedge my bet and ask here - guys that actually have / use the beast.

Question: What configuration(s) would be good / best to run a flavor of BASIC (were there multiple possible dialects of BASIC that could be run? Was there only one “official” one? Pros & cons of some?). What board #’s - revs & functions would I need to have a working system (floppy controller, BASIC, printer, RAM - anything else?). What diskettes are ESSENTIAL? Which are desirable? What RAM (capacity) is 'recommended' for a good BASIC environment? When I used one eons ago, I didn’t have access to the innards (it was rack mounted) so I never did see inside the beast. But I remember to this day that I REALLY liked it! I understand there is a Cromemco user group somewhere (Google groups? Here somewhere?) - but I hear it’s “invitation only” or you have to apply or something? Does anyone know what I’m talking about (I don’t! LOL)?

Another question: What do folks here think of eBay vintage pricing? Personally, I think it can easily get out of hand. I’m on a fixed income and can’t bid against Steve Balmer and spend $4K on a cherry IMSAI or whatever!! :) Are swap meets / ham fests, etc. better bets? I’m in the mid-west (Tulsa area). So I think Dallas would be the closest area?

Any hints, tips, kinks would be appreciated! Anything to watch out for? Good rev boards? Bad rev boards?

Above all, I appreciate your patience with me, Likely your answers will beget more questions, but eventually I will (probably!) shut up! :)

Thanks in advance!
 
First of all, welcome to VCFED.

Don't forget that you will be under moderation for the first 10 posts. It would also be helpful to add your location to your profile (if you are able to). This avoids mentioning it in the posts.

Yes, ePay prices are really variable :). There are some good deals to be had - and, for the others, there is a bidding frenzy!

A small system (to run CP/M or CDOS) would be a ZPU (Z80 processor board), a 64KZ RAM card (or similar) and a disk controller (e.g. 16FDC or 64FDC).

You may have to go 5 1/4" floppy drive or (better still) a floppy drive emulator.

The disk images are available (many disk images!), so you would be advised to join the Cromemco google group - and Github repository. I can't post the links from the account I am currently on... I can do that tonight for you. It is not 'invitation only' in that sense, but you do have to apply and you will be granted access providing you agree to the terms and conditions of access. Sometimes it does take a while - but it is worth the wait...

The 64KZ RAM board isn't the best... But, if you get one that tests good...

Obviously, once you have CP/M running - you should be able to run many flavours of BASIC.

It really depends upon where you want to take your system...

You could expand it and incorporate (for example) the DPU (A Z80 and 68000 processer CPU board). However, in order to run any 'sensible' software for the 68000, you will need a different memory board.

I would suggest starting simple and working your way up.

There are even Dazzler graphic card recreations if you want to go down this route.

I was 'lucky' and found a number of Cromemco cards on their own - but the chassis had gone in the bin many years previously. I acquired a chassis (thank you Marcus) and someone was selling a DPU that I managed to acquire. I had to 'fix' the power supply unit. I had also to remove one of the backplane connectors on the BlitzBus due to corrosion - and clean the rest up. Some of the cards don't work - so I have a pile of working cards, almost working cards and dead ducks. I still have a few to test - but I have a working minimal system. The next thing I am working on (a Christmas job) is to get a working floppy drive.

There you go, let's start the conversation...

Dave
 
Hi Dave,

Thanks for the warm welcome.

I found out I was under moderation when I read an older but interesting post re Cromemco - and realized I couldn't directly DM the user. Also, there's a little banner at the bottom of my page (for now), that reminds me. :)

Wow, I REALLY appreciate you taking the time & effort for the detailed reply.

Before I forget, yes, please do share the link for the Google Cromemco group. I'll apply and see what happens!

You've given me a good starting point / baseline to get started I think. It's very much appreciated. I just need to keep my eyes (and wallet?!) open, and hope I can come across a good frame and cards to get started with. I can do some trouble-shooting and electronic service / repair (got good meter, decent soldering skills, ha!) so 'near working' condition might be on the table for the right stuff. Afterall, "If it's not the fuse, it's something else!" right? I've got a fair background in IT (40+ years in random jobs, some code & scripting {BASIC, APL, a few OS's, Windows, Python, HTML, etc.), desktop support and Service Desk (aka "helpdesk") management, etc. . I'm pretty sure I've forgotten whatever CP/M I ever knew though. At my age - it seems to be "use it or lose it".

More (lots! Sorry!) neophyte questions for you (& anyone else interested in helping!):
1) Do you know of any index / compendium / glossary, etc; - that might list useful cards - maybe by part # and/or function? Realizing there's likely a vast selection for a S-100 bus, but removing the more exotic - what are the fundamentals (and BASIC's? :) ). Are there any cards / adapters that help make use of 'modern' peripherals (via USB, etc.? So I wouldn't have to buy an old Okidata, Epson or Diablo or something to print? A SATA card {a man can dream!} and so on?!.

2) As I recall from a bit of reading, the Z-2 & Z-2D were both available in manufactured OR kit form, is that correct? If so, other than visual inspection of a unit, is there a way to tell (maybe by serial # prefix/suffix or something?) whether the unit I might be looking at was a kit or factory built?

3) Presuming I could be fortunate enough to lay my hands on a Z-2D, what are the basic / mission critical diskettes I'd want/need to boot to a prompt and be able to "do something"? Are there relevant release #'s (presumably latest is always best {bittersweet snicker here}). Obviously some sort of CP/M OS, but if I just wanted to start simple - with something resembling a cherry Cromemco - e.g.: bought from factory, enough to boot and have a little fun. And at some point acquiring a nice BASIC (the more robust / expansive, the better, but I'm not sure how robust the dialects of BASIC's are? Was there ever a "Cromemco" branded BASIC or were they all 3rd party? Was there a distinct 'winner' dialect that folks preferred for some reason (extensive libraries, price, whatever)? For the life of me, I just can't remember what diskettes I had to use with the system I used back in the late '70's.

Sorry to sound like a kid in a candy store - asking you to recite everything from Adam to Armageddon here, but "I have questions"! LOL Thanks for bearing with me.

With Great Appreciation,

--Pete
 
granzeier said:
S-100 Computers has a lot of information on S-100 boards, including a bunch of Cromemco stuff. You can find the list here: http://www.s100computers.com/Hardware Index Page.htm
I've used this site for a lot of info on my boards, and rarely am disappointed.
Click to expand...
Thank you very kindly! Bookmarked!!! I DO appreciate that.
Right now I'm scratching my head on the differences between C/PM and Cromix. Do I even need / want Cromix? I intend to have a single user system primarily running some dialect of BASIC. I'll figure it out.

Again, I appreciate your help as I start down this road again (~38 years later!).

Cheers,

--Pete
 
Cromix is very memory hungry.

You can run an old version of Cromix on a Z80 with a single 64KZ memory card. However, it can do nothing more than list a disk directory!

You can make a single-user Cromix system with two 64KZ memory boards. However, unless you have used Cromix in the past (or want to get it running for the interest), I wouldn't particularly bother myself.

With a ZPU, 64KZ and disk controller (16FDC) you can use a raspberry pi as a terminal emulator and have a basic system. I use minicom on my pi in conjuction with an RS232 USB converter.

The disk controller has an inbuilt machine code monitor (RDOS). This can be used to run tests on the memory and 'play about' in machine code.

I have written a program to convert a binary file into a series of RDOS memory modification commands. This allows the pi to act as a very fast typist for downloading (and executing) programs.

There were a number of programs originally written for loading from a paper tape. These are ideal for loading from the pi and playing around...

Dave
 
@daver2 & @granzeier

I can't thank you guys enough for the info so far. I think that addresses most of my questions, etc. I'm sure I'll have plenty more as time goes on. I need to find a nice chassis and populate it,

Since I'm planning on it being a single user system, I guess I have no need for Cromix - based on what I've read here. While I'm probably more familiar with some *nix systems (HPUX, Solaris, etc.) it's been so long - the (re-)learning curve for it vis-a-vis CP/M probably would be comparable, and with little "return on investment" - especially considering the resource usage (RAM, I presume).

One question though: If you (anyone reading this!) were hunting for a Z-2D chassis today, would you be content to troll eBay (ePay! Loved it!), or is there a better resource even more likely to pay off? For example, if I were hunting for a Model 33 Teletype, I might want to subscribe to "greenkeys" maillist or something? There probably aren't any hamfests / flea markets of note within at least a couple hundred miles of here. I might be willing to travel further but would want to know there was something worth traveling for - waiting on the other end of the trip.

Thanks again everyone - for the warm welcome and, of course, for the technical advice & suggestions.

To be continued - as further questions arise!

Have a great weekend,

--Pete
 
Greetings All,

Is there a way to tell if a Cromemco was factory built or kit built? From what I understand, the Z-2 & Z-2D were available in both forms (kit or factory built). Perhaps by serial number or a revision number or something? Or do you simply have to eyeball the quality of any cabling / solder points in the chasis?

Thanks,

--Pete
 
Not to my knowledge, but there are a few people over on the Cromemco Google group who either worked at Cromemco, or worked on repairing the machines for a living, so they would know for sure.

The usual way for me would be to eyeball the soldering...

We had a few hundred boards refurbished for us at work a few years ago and brought up to the latest revision (as it was back in the day if course). One IC had to be replaced on a very old revision upgrade (and it was an easy spot from the part number). The technician's soldering was pristine! But he does it day in day out and has done for 50 years...

Some home-built equipment I have seen, the soldering is shocking...

Dave
 
Thanks again @daver2 !
Yes, I've been soldering for quite some time, though not so much lately. Got really decent at it when I worked as Chief Engineer at a few commercial broadcast radio stations. I know exactly what you're speaking about. That why the "pucker factor" is high when I see any "Griefkit" (Heathkit) stuff coming up on eBay or other forums. I've spent too much time re-doing other folks errors. Including using acid core on electronics,heat too low, using half a spool of solder for 6 connections, etc. You've seen it - you get the idea. I think conservatively, 70% of the problems with "broken" Heathkits is solder related - shorted, cold, etc. I want to avoid that if I can - with any Z-2D I might pick up. I only recently learned these were available as both factory and kit forms.

EDIT: I will try to post to the Google group and see what they know about this over there. Duuhhh! Great idea!
 
Thanks @nullvalue , looking at CDOS a little. It seemed to ring a distant memory from long ago.

I appreciate that site. I'll look over a few of the manuals and see what looks tempting! :)

I REALLY appreciate this forum. The responses and depth of knowledge is most impressive!

Have a great Friday everyone!

--Pete
 
>>> I REALLY appreciate this forum. The responses and depth of knowledge is most impressive!

Thanks Pete.

We always appreciate good feedback...

Dave
 
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