Zen Z80 editor-assembler for the Grant Searle & RC2014mini/micro/classic - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

DavidMS · 20th Mar 2023, 8:23 am

Quote:

Originally Posted by ortek_service

Yes, and the Z80-SIO is probably much-rarer than the CPU - as not many Z80 systems had a Z80-SIO IC fitted as standard (sometimes opting for an 8251 etc, if only Asynchronous-serial was required - like in the Tatung Einstein - Maybe it was a bit cheaper?)

Gemini (successor to NASCOM) had a basic networking solution for their office setup, one of my jobs during my graduate placement with them was sanding off the details from the 'networking' chip - which they sort of implied was something special - it was in reality a Z80 SIO ...

SiriusHardware · 20th Mar 2023, 8:37 am

Briefly aside, I was offered a complete working Gemini system from a customer's premises when it became redundant as it was being replaced with networked PCs, this was early-mid 90s. It was complete with matching monitor and keyboard and had been doing its job as the heart of an alarm receiving centre for a good few years before then.

Had I been aware of its NASCOM heritage at the time, I might have saved it. But... I didn't. When it was running it was never possible for me to get near it and it was so reliable it never needed any attention. I assume it must have run CP/M?

DavidMS · 20th Mar 2023, 10:46 am

Quote:

Originally Posted by SiriusHardware

Briefly aside, I was offered a complete working Gemini system from a customer's premises when it became redundant as it was being replaced with networked PCs, this was early-mid 90s. It was complete with matching monitor and keyboard and had been doing its job as the heart of an alarm receiving centre for a good few years before then.

Had I been aware of its NASCOM heritage at the time, I might have saved it. But... I didn't. When it was running it was never possible for me to get near it and it was so reliable it never needed any attention. I assume it must have run CP/M?

Yes, it would have been running CP/M, they did have their own operating system but I don't think that supported floppy / hard disks, so you were effectively forced to go down the CP/M route.

Phil__G · 20th Mar 2023, 2:07 pm

Or Polydos, that was our choice at BT.
Polydos didnt have the start-at-100h imposition that CP/M has and was easier to integrate into the Nascom/Gemini memory map.

Also, whilst you were saving up for a disk system, Gemini had RP/M which allowed you to develop CP/M software with storage on cassette tape!
RP/M was a 'cp/mified' monitor that supported most bdos calls such that simple CP/M programs wouldnt know the difference.
Once an application was loaded (say MBASIC etc), RP/M allowed you to stream just one file on tape.

DavidMS · 20th Mar 2023, 3:10 pm

Quote:

Originally Posted by Phil__G

Or Polydos, that was our choice at BT.
Polydos didnt have the start-at-100h imposition that CP/M has and was easier to integrate into the Nascom/Gemini memory map.

Also, whilst you were saving up for a disk system, Gemini had RP/M which allowed you to develop CP/M software with storage on cassette tape!
RP/M was a 'cp/mified' monitor that supported most bdos calls such that simple CP/M programs wouldnt know the difference.
Once an application was loaded (say MBASIC etc), RP/M allowed you to stream just one file on tape.

I very much liked Polydos, one of my long term to-dos is to un CP/M my NASCOM 2 and re-install Polydos

Phil__G · 20th Mar 2023, 4:01 pm

Neal Crook is your man!

DavidMS · 20th Mar 2023, 8:09 pm

Quote:

Originally Posted by Phil__G

Neal Crook is your man!

we have spoken

20th Mar 2023, 8:37 am	#22
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 9,745	Re: Zen Z80 editor-assembler for the Grant Searle & RC2014mini/micro/classic Briefly aside, I was offered a complete working Gemini system from a customer's premises when it became redundant as it was being replaced with networked PCs, this was early-mid 90s. It was complete with matching monitor and keyboard and had been doing its job as the heart of an alarm receiving centre for a good few years before then. Had I been aware of its NASCOM heritage at the time, I might have saved it. But... I didn't. When it was running it was never possible for me to get near it and it was so reliable it never needed any attention. I assume it must have run CP/M?

20th Mar 2023, 2:07 pm	#24
Phil__G Hexode Join Date: Mar 2011 Location: North Yorkshire, UK. Posts: 495	Re: Zen Z80 editor-assembler for the Grant Searle & RC2014mini/micro/classic Or Polydos, that was our choice at BT. Polydos didnt have the start-at-100h imposition that CP/M has and was easier to integrate into the Nascom/Gemini memory map. Also, whilst you were saving up for a disk system, Gemini had RP/M which allowed you to develop CP/M software with storage on cassette tape! RP/M was a 'cp/mified' monitor that supported most bdos calls such that simple CP/M programs wouldnt know the difference. Once an application was loaded (say MBASIC etc), RP/M allowed you to stream just one file on tape. Last edited by Phil__G; 20th Mar 2023 at 2:13 pm.

20th Mar 2023, 4:01 pm	#26
Phil__G Hexode Join Date: Mar 2011 Location: North Yorkshire, UK. Posts: 495	Re: Zen Z80 editor-assembler for the Grant Searle & RC2014mini/micro/classic Neal Crook is your man!