UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Computers

Notices

Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

Closed Thread
 
Thread Tools
Old 27th Jul 2022, 3:22 pm   #1
AdrianH
Octode
 
AdrianH's Avatar
 
Join Date: Mar 2020
Location: Blackburn with Darwen, Lancashire, UK.
Posts: 1,234
Default Just a question on CP/M computers?

It has been many a year since I had a Nascom or Gemini computer system, but do have the odd bit of interest to get something once again. I have seen a couple of single board computers, one based on the Z80 and one on the V20 for around 50.

So I was wondering if there is any pro's and con's to each one and which one should I consider getting to try and learn the system again, see if i could write the odd program etc. Just after thoughts.

Adrian
__________________
Asking questions and learning, or trying to!
Youtube EF91Valve
AdrianH is online now  
Old 27th Jul 2022, 4:58 pm   #2
Michael Haardt
Triode
 
Join Date: May 2021
Location: Titz, Germany.
Posts: 44
Default Re: Just a question on CP/M computers?

I would get one with a Z80 CPU. The V20 only offers the 8080 instruction set, which excludes a fair amount of nice software.

Michael
Michael Haardt is online now  
Old 27th Jul 2022, 5:35 pm   #3
SiriusHardware
Dekatron
 
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 9,214
Default Re: Just a question on CP/M computers?

For something self-contained, maybe a Tatung Einstein if you can find one - their OS is a CP/M clone, I seem to remember.

Or an Amstrad CPC6128 - fairly sure they could run CP/M but I don't think it was ROM based so you might need to find one with the CP/M discs still present and intact.
SiriusHardware is online now  
Old 27th Jul 2022, 6:16 pm   #4
Timbucus
Octode
 
Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
Posts: 1,240
Default Re: Just a question on CP/M computers?

The Amstrad 6128 once you repair the 3" drive is quite a good CPM machine once you have some disks which can get expensive - and the monitor adapter if it does not have one as of course the PSU is in the monitors.

Did you mean one of the modern single board builds like the Z80-MBC2 that can use an SD card to simulate drives - they give a really retro experience but, with more modern services...

https://hackaday.io/project/159973-z...w-z80-computer

I have not built one of them but, I did build one of Grant Searl's http://www.searle.wales/ Z80 SBC's...

https://youtu.be/G_iBL94jGdw

The other one that has taken my fancy is the RC2014 which offers a lot of expandability:

https://rc2014.co.uk/
Timbucus is offline  
Old 27th Jul 2022, 6:35 pm   #5
Mark1960
Heptode
 
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
Posts: 922
Default Re: Just a question on CP/M computers?

I would suggest looking at the RC2014 or one of the alternate systems based on the same bus. SC131 is quite a neat cased Z180 system if you are not planning on expanding hardware. SC126 or SC130 are also z180 based. There is also a few Z80 based systems if you search for z80 or z180 on Tindie using either the standard RC2014 bus or 50 pin headers.

Maybe worth taking a look at the RC2014 google group or RC2014.co.uk, or https://smallcomputercentral.wordpress.com/kits/
Mark1960 is offline  
Old 27th Jul 2022, 6:50 pm   #6
AdrianH
Octode
 
AdrianH's Avatar
 
Join Date: Mar 2020
Location: Blackburn with Darwen, Lancashire, UK.
Posts: 1,234
Default Re: Just a question on CP/M computers?

I believe I was thinking of the Z80-MBC2, the V20-MBC was the other one. I have a few Z80 and peripheral chips somewhere stashed away in a metal box. The only thing I am uncertain of is I believe you need a terminal via USB to input or see anything, (via a PC of course so things like minicom or putty etc).

It is a basic restart again for me.
When I had the Nascom, after having had a ZX81 I wrote a machine code program with an 8 bit A2D that read in as APT weather satellite on 137 MHz and I could display a pass of the satellite, 8 bit was a bit poor in resolution but it worked. I did a few other packages, then got a Gemini system with 5 1/4 in drives and a 5 Meg hard disk that had, that system had office software and a few games, plus some weird graphics program that drew intricate circular patterns. But after that I started work in another electronics area the boxes were just moved around until I got rid of them. All this is going back many years ago.

The prices for the complete PC's seem a bit high for a maybe idea so I think I would stick to something basic such as the MBC's

Adrian
__________________
Asking questions and learning, or trying to!
Youtube EF91Valve
AdrianH is online now  
Old 27th Jul 2022, 8:43 pm   #7
Phil__G
Hexode
 
Join Date: Mar 2011
Location: North Yorkshire, UK.
Posts: 328
Default Re: Just a question on CP/M computers?

Hi Adrian, I'm also a Nascom dinosaur and a bit of a CP/M nut
I still have my Ferguson Bigboard (like a Xerox 820 etc) from around 1982 ish but also a few 'modern' CP/M machines (including a Nascom 4!). I have a Z80MBC2 and I dont like it. For me it has a similar problem to the Grant Searle CP/M board, in that the use of compact flash or SD makes creating CP/M disks and transferring files a 'right faff', so much so that although its a great CP/M machine , I rarely use it. Its also non-conventional circuitry so could be awkward when anything goes wrong. The RC2014 is bog standard TTL, all good stuff.
I also have three 'Z80 Playground' CP/M computers, now this one has a modified BDOS that works directly with FAT, on a USB stick. To transfer files you just pull the stick, plonk it into your PC, copy files, and put it back in the CP/M box. This is a revelation, it really is. Massively convenient. Unfortunately the designer John Squires hurt his back and has gone AWOL so the project has gone a bit stale. The Playground remains my CP/M mainstay though, I did a 8255 I/O card for it:
https://www.youtube.com/watch?v=cu_yJXgvruo
https://www.youtube.com/watch?v=BWP404CkBA4
I have thought about doing a CH376 card for the RC2014 such that it too could run the FAT BDOS- one of too many projects!

My most recent addition has been the RC2040. This is a Z80 CP/M board with the usual 16 x 8Mb drives but its the size of a credit card. Its the most portable CP/M box you could imagine. Its a hardware emulation of course on an RP2040 but a perfect emulation - actually of a complete RC2014 - hence the name. It even has an uncommitted 8-bit IO port. I did a video on using the port:
https://www.youtube.com/watch?v=HuaUUFC2Goo
Its a kit, a 5 minute build, and Derek the designer will solder the one awkward component if you ask nicely (SD slot) It comes with the O/S loaded & ready to go, plus a download facility, BBC & MS basics, Hitchhikers, etc. A tad over 40 which is a bargain: https://www.extremeelectronics.co.uk/the-rc2040/
All these boards need an external terminal, like Teraterm or Putty, I bought a 2nd hand HP netbook for 30 specifically to use as a terminal, its been great!
Summary - all these boards are brilliant CP/M machines. The file transfer and disk creation on the Rc2014 and Z80MBC2 is a right faff. The RC2040 disks (on micro SD) are easy but you still have the file transfer faff. Overall my favourite by a mile is the Playground. The files and schematics are all on Github so its still doable even in Johns absence. Second fave would be the RC2040. Hope all this waffle is of some help
Cheers
Phil

Last edited by Phil__G; 27th Jul 2022 at 9:12 pm.
Phil__G is online now  
Old 27th Jul 2022, 9:14 pm   #8
AdrianH
Octode
 
AdrianH's Avatar
 
Join Date: Mar 2020
Location: Blackburn with Darwen, Lancashire, UK.
Posts: 1,234
Default Re: Just a question on CP/M computers?

Thanks for the comments Phil, especially regards the SD card. That is something I thought was a good idea, yes it would be better if one could use USB drives, but my PC has SD card slots as well so copying files from my PC (Linux) may not be an issue?

I will be honest and say that I have never modified any Operating systems, BIOS or BDOS (Boot disk OS?), my only thing at the time would have been working with the Nascom monitor system giving access to all things. But that as I said was that many years ago everything has been forgotten now.

I do think I will go for the Z80-MBC2 eventually, only because I believe I have the Z80 CPU and some logic and peripheral chips tucked away, even some ram . Soldering I can do generally because it is not surface mount, or my eyesight may be an issue. I am also browsing some YouTube videos on it at present, there is a lot of options out there I can appreciate that, but it is finding somewhere to start and relearn everything.

Cheers

Adrian
__________________
Asking questions and learning, or trying to!
Youtube EF91Valve
AdrianH is online now  
Old 27th Jul 2022, 9:27 pm   #9
Phil__G
Hexode
 
Join Date: Mar 2011
Location: North Yorkshire, UK.
Posts: 328
Default Re: Just a question on CP/M computers?

I should have said, the RC2040 is the second fave and it looks like Derek has dropped his prices - its now listed at 33. I cringe when I think what the Fergy BigBoard cost !!!
Quote:
Originally Posted by AdrianH View Post
but my PC has SD card slots as well so copying files from my PC (Linux) may not be an issue?
The physical form isnt the problem Adrian - within CP/M its not FAT, so files have to be built up inside a huge file that represents a 'disk'. This process is the faff - see 'CPMTools'
The Z80MBC2 doesnt have much conventional (ie junk box) glue, its held together by an Arduino-type chip. You cant just physically change an eprom for example, its in the AVR chip. Of the Z80MBC2 and RC2014, I would probably go RC2014 as its entirely conventional. Maybe a 'mini' with the CP/M board. Your choice, you wont be disappointed with any of these boards, I only comment cos I'm using them all

Last edited by Phil__G; 27th Jul 2022 at 9:38 pm.
Phil__G is online now  
Old 27th Jul 2022, 9:29 pm   #10
AdrianH
Octode
 
AdrianH's Avatar
 
Join Date: Mar 2020
Location: Blackburn with Darwen, Lancashire, UK.
Posts: 1,234
Default Re: Just a question on CP/M computers?

What price the Nascom2 in today's money?

Adrian
__________________
Asking questions and learning, or trying to!
Youtube EF91Valve
AdrianH is online now  
Old 27th Jul 2022, 10:43 pm   #11
Phil__G
Hexode
 
Join Date: Mar 2011
Location: North Yorkshire, UK.
Posts: 328
Default Re: Just a question on CP/M computers?

Mine? It's a Nascom 4, which is an FPGA design by Neil Crooke , Nascom 2's fetch silly money and 1s even more, foolishly, I skipped mine decades ago!!!
Attached Thumbnails
Click image for larger version

Name:	IMG_20220727_235208.jpg
Views:	39
Size:	48.9 KB
ID:	261681  

Last edited by Phil__G; 27th Jul 2022 at 10:53 pm.
Phil__G is online now  
Old 27th Jul 2022, 11:02 pm   #12
Mark1960
Heptode
 
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
Posts: 922
Default Re: Just a question on CP/M computers?

There is also CP/M IDE for the RC2014 which supports the FAT file system.
Mark1960 is offline  
Old 27th Jul 2022, 11:27 pm   #13
Phil__G
Hexode
 
Join Date: Mar 2011
Location: North Yorkshire, UK.
Posts: 328
Default Re: Just a question on CP/M computers?

Hi Mark, the problem is that CP/M doesnt (natively) so even feilipu's IDE interface has one file per CP/M drive (all under FAT, yes) but thats just a 'carrier' and all the individual CP/M files are represented within that one file as 128 byte sectors. An awful utility called 'CPMTools' is necessary to collect CP/M format files and to bung then into the one, common FAT file so that he standard CP/M BDOS can read them using trad CP/M sector-read conventions. Honestly, when you've a lot to do, its a real pain.
The Playground FAT BDOS gives CP/M itself native FAT compatibility, with separate files under FAT for each CP/M file, like MSDOS (but without subdirs etc). No CPMTools or faff, and instantly interchangeable between CP/M-80 and a PC

Say I have a batch of files on my PC that I need on a CP/M box. With the playground that would take seconds. With CPMTools it takes much, much longer. You cant do a 'DIR' or 'ls' to see what CP/M files are on there, its just one FAT file. Same problem in the other direction, using CPMTools to pull individual files from the 'carrier' file whereas with the FAT BDOS its just plug in the USB stick, DIR to see whats there, & copy. Or the Windoze equivalent. SO much easier! feilipu's IDE is just different hardware, same problem...

Last edited by Phil__G; 27th Jul 2022 at 11:41 pm.
Phil__G is online now  
Old 27th Jul 2022, 11:52 pm   #14
AdrianH
Octode
 
AdrianH's Avatar
 
Join Date: Mar 2020
Location: Blackburn with Darwen, Lancashire, UK.
Posts: 1,234
Default Re: Just a question on CP/M computers?

The issues with most of the ideas is they are currently out of stock . The Z80 playground, the RC2014 mini, or classic from Z80kits. The one in stock is the RC2040. To get the mini and the CP/M expansion board puts the price to over 100.

It has been interesting trying to scan the various sites and see what is available but I guess the shortage of chips is causing a big issue.


I can get the Z80-MBC2 or V20-MBC now, so I think to start with I will go with the Z80-MBC2, pick up some online documentation for CP/M 2.2 and have a read and start from there. If I wish to progress after that the unit could always end up on the auction site again.

Adrian
__________________
Asking questions and learning, or trying to!
Youtube EF91Valve
AdrianH is online now  
Old 28th Jul 2022, 12:55 pm   #15
AdrianH
Octode
 
AdrianH's Avatar
 
Join Date: Mar 2020
Location: Blackburn with Darwen, Lancashire, UK.
Posts: 1,234
Default Re: Just a question on CP/M computers?

The ready made board has been ordered and will reach me sometime next week. So I hope to have a play when it arrives and get back into some Z80 language programming slowly. So I will ask admin to close this thread.

Thanks all for assistance.

Adrian
__________________
Asking questions and learning, or trying to!
Youtube EF91Valve
AdrianH is online now  
Old 28th Jul 2022, 1:00 pm   #16
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 19,601
Default Re: Just a question on CP/M computers?

Thread closed at OP's request.
__________________
Graham. Forum Moderator

Reach for your meter before you reach for your soldering iron.
Station X is online now  
Closed Thread

Thread Tools



All times are GMT. The time now is 10:34 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.