IBM PS/2

[vbdasc]

I'm sorry if this question has been already asked; I couldn't find anything. So, would it be possible to emulate certain IBM PS/2 models for which ROM dumps are available? For example, Model 30 with 8086 or 80286. It would be interesting to play with the MCGA

[SarahWalker]

Model 30-286 is already emulated, as of rev 648. As for other PS/2s - watch this space.

[altheos]

Great job on PS/2 emulation Sarah.

About MCGA, i think PCem does not have such a card. If I remember correctly MCGA used 64 Kb of VRAM and was incompatible with EGA mode

Speaking of PS/2, later models had IBM 386SLC and 486SLC processors (model 40, 55 ..). They were not the same as Cyrix similarly named CPU and instead were built by IBM. Does someone have any tech sheet on these CPUs, as it would be a nice addition to PCem ?

[omarsis81]

PCem doesn't have a MCGA card because they don't exit (as a standalone card).
Only came onboard with certain PS/2 models

You're right about not being compatible with EGA

[omarsis81]

For those who want to test the model 50, you need to create the "i8550021" folder inside "roms" and there you'll need to place one or both of these files:
90x7423.zm14
90x7426.zm16

[ppgrainbow]

Great work on the IBM PS/2 emulation so far!

Now would it be possible to add SCSI emulation? The IBM PS/2 Models 57 SX, 65 SX, P75, 80, 90 XP 486 and 95 XP 486 all have onboard SCSI hard disk controllers. They're all MCA 32-bit.

If SCSI emulation is added, PCem may have the capability to support up to 4 SCSI hard disks or CD-ROMs. Plus, I believe that the Model 80 also had a integrated IBM XGA graphics card...the brainchild behind the 8514/A graphics card emulation.

That's something that you might want to look into.

[SarahWalker]

SCSI emulation would be possible. I do have some SCSI code from other projects, though adding the infrastructure to make it all properly configurable would be a reasonable amount of work.

[ppgrainbow]

SCSI emulation would be possible. I do have some SCSI code from other projects, though adding the infrastructure to make it all properly configurable would be a reasonable amount of work.

That would sound awesome to implement SCSI support found in other projects on to PCem!

I also wondering if it would be possible to use either the internal IDE or SCSI emulation on AT clones such as the AMI 386SX/DX and AMI 486. The AMI Win486 BIOS has the capability to use IDE hard disks, ESDI or SCSI hard disks.

If SCSI emulation is used, you would need to disable the internal IDE.

I remember when I had a 486-based PC in late 1993, it had a 1.2 GB SCSI hard disk and IDE hard disks weren't in use at all.

Speaking of SCSI hard disk emulation, some SCSI hard disks had more than 63 sectors per track which causes operating systems like DOS to not recognise the full hard disk capacity.

For example, the Toshiba MK538FB 1.2 GB SCSI hard disk had 1,979 cylinders, 15 heads and 79 sectors per track for a total of 1,200,698,880 bytes (1.12 GB). However, FDISK only recognised hard disks up to 63 sectors per track which puts the usable capacity at 957,519,360 byes (913 MB).

[vbdasc]

For those who want to test the model 50, you need to create the "i8550021" folder inside "roms" and there you'll need to place one or both of these files:
90x7423.zm14
90x7426.zm16

Thanks... but didn't the PS/2 model 50-021 come with a 20Mb MFM disk, connected to a MCA ST506/412 controller? I believe Sarah Walker mentioned in another thread that PS/2 ESDI disks would be supported...

[vbdasc]

Wow, thanks for supporting this little MCA machine, Sarah... Now, I can finally see how does this cryptic IBM ABIOS work under OS/2 1.3

[SarahWalker]

Yes, the PS/2 ESDI controller is emulated. The ROM files you need are 90x8969.bin and 90x8970.bin.

I did look at the MFM controller, but there's no documentation available that I could see, and it appears to use a completely different command set to any of the normal controllers.

[altheos]

PCem doesn't have a MCGA card because they don't exit (as a standalone card).
Only came onboard with certain PS/2 models

You're right about not being compatible with EGA

Indeed, MCGA chip came with entry level PS/2 (earlier 8525 ans 8530) but can't pcem emulate onboard video chipsets ?
Finding the mcga BIOS would certainly be harder.

[omarsis81]

Commit d496325 - Added PS/2 Model 55SX emulation.

PS/2 fans rejoice!