How do launch/boot UCSD for imsaisim

[preiner]

Im using high nibble imsai 8080 kit, however even a generic answer would help.

Currently CPM is running fine. Do I simply add UCSD .dsk files as additional drives and run UCSD after booting CPM or do I need to direct boot to UCSD psystem environment directly? And if so, which .dsk is the boot image and what address does it want to be loaded at?

Thanks for any help

[udo-munk]

For this it doesn't matter if you are using the IMSAI 8080 clone or z80pack imsaisim on a PC.
You need to directly boot UCSD with ucsd-iv-1.dsk in drive A: and ucsd-iv-2.dsk in drive B:. The first disk is bootable, the 2nd is not, contains additional system programs and examples. First stage boot code always gets loaded to address 0 in this machine.

[preiner]

Thank you so much for responding.
I suspected I would just mount these 2 disks like you described.

Where I am lost is that the HN imsai kit has several memory mappings that I can choose from each with different roms. (see attached) system.conf.txt

I tried with both memory maps 1&2 which use mpu-a-rom (only one that seems to support booting) and after the disks get mounted, my console is non-responsive.

Is there a psystem boot rom or maybe a boot loader that supports both cpm & psystem?

So basically just I cant determine how to get disk1 bootstrapped in

[udo-munk]

Thank you so much for responding. I suspected I would just mount these 2 disks like you described.

Correct.

Where I am lost is that the HN imsai kit has several memory mappings that I can choose from each with different roms. (see attached) system.conf.txt

I tried with both memory maps 1&2 which use mpu-a-rom (only one that seems to support booting) and after the disks get mounted, my console is non-responsive.

Memory map 1 is fine for CP/M and UCSD p-system, map 2 adds the VIO ROM and the VIO only is supported by CP/M.
All provided ROM's support booting the OS's of course, you can try a different ROM by modifying the filename in
memory map 1.
You might be using the wrong console, the one for the VIO instead of the serial terminal and the VIO will not respond when booting UCSD p-system.

Is there a psystem boot rom or maybe a boot loader that supports both cpm & psystem?

All boot ROM's do, they just load the first sector on the first track to memory location 0 and the bootable
disk images contain boot code on that sector for the next stage.

[preiner]

Hi,
I was able to boot ucsd-iv-1 with memory map 1 and mpu-a-rom after fiddling around a lot. Apparently while CPM will autoboot when the power button is flipped on, PSYSTEM wont until I press reset, examine addr 0, and run. Ive tried this a dozen times and for some reason there is a different behavior here. Sometimes it displays on the serial usb console, sometimes it displays in the web tty.

I was able to also load the startrek disk and see it in UCSD filer and execute it.

However, virtually every other UCSD dsk image will mount in the emulator but wont be visible to filer. (Press V in filer, and volume isnt listed)

I thought maybe most .dsks are for older psystem that MIGHT have different format. So i tried every variation i could. I could not boot any other UCSD disk. (ucsd-i5-1, ucsd-ii-1, ...) None of them will boot nor will the even show up as additional disks when iv-1 is booted.

Do you have any ideas why this may be? If i cant mount them, would it be possible to extract the files from them? I found a port of cpmtools for windows that works fine and i can access cpm disks, but I cant seem to figure out how to even get a disk listing of the UCSD dsks.

I do have access to wsl and I could even create a linux vm if thats truly required but im not fluent in linux and without detailed steps this will take several days at least

[udo-munk]

Hi, I was able to boot ucsd-iv-1 with memory map 1 and mpu-a-rom after fiddling around a lot. Apparently while CPM will autoboot when the power button is flipped on, PSYSTEM wont until I press reset, examine addr 0, and run. Ive tried this a dozen times and for some reason there is a different behavior here. Sometimes it displays on the serial usb console, sometimes it displays in the web tty.

This is odd and I cannot reproduce what you are doing there. The procedure to autobot the system with MPU-A/B ROM from IMSAI is:

1. while the machine is powered off put a BOOTABLE disk into the first drive
2. switch power on
3. flip the RUN switch

Always works reliable. The ROM's load first sector from the disk to address 0 and then jump to address 0. If you use a disk in the first drive with no good boot code the machine will execute whatever code was on that disk, probably runs off.

However, virtually every other UCSD dsk image will mount in the emulator but wont be visible to filer. (Press V in filer, and volume isnt listed)

I thought maybe most .dsks are for older psystem that MIGHT have different format. So i tried every variation i could. I could not boot any other UCSD disk. (ucsd-i5-1, ucsd-ii-1, ...) None of them will boot nor will the even show up as additional disks when iv-1 is booted.

I have only ported UCSD p-Sytem IV to the IMSAI, the other versions only are ported to the z80pack cpmsim machine. Different hardware, so won't work on an IMSAI.
With IV they changed the disk format, not using a skew anymore as in the releases before that. It is possible to convert disks, the procedure for this is explained here: https://www.icl1900.co.uk/unix4fun/z80pack/doc_ucsd.html

Do you have any ideas why this may be? If i cant mount them, would it be possible to extract the files from them? I found a port of cpmtools for windows that works fine and i can access cpm disks, but I cant seem to figure out how to even get a disk listing of the UCSD dsks.

There is a user land UCSD filesystem implementation for UNIX systems, so that one can mount UCSD disk images:
https://ucsd-psystem-fs.sourceforge.net/ucsd-psystem-fs-1.22.pdf
I have used it a decade ago to prepare the UCSD disks for the z80pack machines, but then the author passed away and this was no longer maintained. Nowadays it is difficult to get this working, requires a lot of code changes, nothing one could easily do in a few days.

[sneakywumpus]

Someone picked these UCSD tools up and made them easier to build: https://github.com/jdykstra/ucsd-psystem-fs .

[udo-munk]

Someone picked these UCSD tools up and made them easier to build: https://github.com/jdykstra/ucsd-psystem-fs .

Cool, thanks, I'll have a look how much trouble it is to build on WSL under Ubuntu or on the Raspberry Pi. Sure would be nice to have that working again.

[preiner]

thanks for that info i thought when the hifh nibble imsai 8080 was in z80 mode it was identical to the cpmsim hw. If it isnt that would explain a lot i think it should be possible to boot cpsim and get these disks to mount. From there it should be possible to write the pascal source code for the games out in some fashion that would allow me to import them to my imsai kit i just cant believe psystem disks werent backward compatible. I remember running psystem at work in the 80s. I just dont remember if we ever had old format disks.

…

________________________________ From: Udo Munk ***@***.***> Sent: Sunday, April 27, 2025 7:13:08 AM To: udo-munk/z80pack ***@***.***> Cc: Paul Reiner ***@***.***>; Author ***@***.***> Subject: Re: [udo-munk/z80pack] How do launch/boot UCSD for imsaisim (Discussion #545) Hi, I was able to boot ucsd-iv-1 with memory map 1 and mpu-a-rom after fiddling around a lot. Apparently while CPM will autoboot when the power button is flipped on, PSYSTEM wont until I press reset, examine addr 0, and run. Ive tried this a dozen times and for some reason there is a different behavior here. Sometimes it displays on the serial usb console, sometimes it displays in the web tty. This is odd and I cannot reproduce what you are doing there. The procedure to autobot the system with MPU-A/B ROM from IMSAI is: 1. while the machine is powered off put a BOOTABLE disk into the first drive 2. switch power on 3. flip the RUN switch Always works reliable. The ROM's load first sector from the disk to address 0 and then jump to address 0. If you use a disk in the first drive with no good boot code the machine will execute whatever code was on that disk, probably runs off. However, virtually every other UCSD dsk image will mount in the emulator but wont be visible to filer. (Press V in filer, and volume isnt listed) I thought maybe most .dsks are for older psystem that MIGHT have different format. So i tried every variation i could. I could not boot any other UCSD disk. (ucsd-i5-1, ucsd-ii-1, ...) None of them will boot nor will the even show up as additional disks when iv-1 is booted. I have only ported UCSD p-Sytem IV to the IMSAI, the other versions only are ported to the z80pack cpmsim machine. Different hardware, so won't work on an IMSAI. With IV they changed the disk format, not using a skew anymore as in the releases before that. It is possible to convert disks, the procedure for this is explained here: https://www.icl1900.co.uk/unix4fun/z80pack/doc_ucsd.html Do you have any ideas why this may be? If i cant mount them, would it be possible to extract the files from them? I found a port of cpmtools for windows that works fine and i can access cpm disks, but I cant seem to figure out how to even get a disk listing of the UCSD dsks. There is a user land UCSD filesystem implementation for UNIX systems, to that one can mount UCSD disk images: https://ucsd-psystem-fs.sourceforge.net/ucsd-psystem-fs-1.22.pdf I have used it a decade ago to prepare the UCSD disks for the z80pack machines, but then the author passed away and this was no longer maintained. Nowadays it is difficult to get this working, requires a lot of code changes, nothing one could easily do in a few days. — Reply to this email directly, view it on GitHub<#545 (reply in thread)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AAMPHU47ASEOLUGVDWIDX2323TQXJAVCNFSM6AAAAAB32CJM4CVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTEOJWGA4TKNA>. You are receiving this because you authored the thread.Message ID: ***@***.***>

[udo-munk]

thanks for that info i thought when the hifh nibble imsai 8080 was in z80 mode it was identical to the cpmsim hw. If it isnt that would explain a lot i think it should be possible to boot cpsim and get these disks to mount.

No it is still an IMSAI, but instead of MPU-A with 8080 or MPU-B with 8085 it has a Z80 CPU card, Cromemco ZPU for example.

From there it should be possible to write the pascal source code for the games out in some fashion that would allow me to import them to my imsai kit i just cant believe psystem disks werent backward compatible. I remember running psystem at work in the 80s. I just dont remember if we ever had old format disks.

If you want to transfer text files with source code only, this also can be done from CP/M. There are CP/M tools that can transfer text only files to UCSD formatted disks. The tools with sources are on the tool source HD in cpmsim.

Back then I wasn't aware about this either, but latest UCSD versions I was using were II. I got aware about the more portable IV system much later, this is a lot easier to port, so the IMSAI and Altair systems got that.

[preiner]

Thanks udo & sneakywumpus.

Since there are no binaries for psystem-fs that I can locate, I have my first compelling reason to take the plunge into linux and learn how to build projects. Ive been putting it off forever due to lack of time. (Now i just have to decide which distro is the best starting point for a Windows user that is actually supported for this project). Several of them super interesting)

[udo-munk]

I have a Windows 11 system I almost never use, and when I'm running software on WSL with Ubuntu Linux. Also a Raspberry Pi is pretty interesting for these things.