Sometimes, programming is just for fun. This is what PREPHV is for Andrei Warkentin. To quote the README:
“This is mostly a huge ugly hack, derived from my
ppc64le_hello code. The running philosophy here is
to throw things together late at night with my family
asleep and see how far I get without a real design
or without a real desire to implement boring things
like IDE (*sigh*) emulation”
Since my day job is maintaining the firmware that it runs on, I decided to have a go (it also ties in with the retro stuff I’ve been blogging about). So…
and I’m off! (yes, this is the very latest qemu and skiboot):
Yes, prephv does clear all thirty two megabytes of guest memory
A quick diversion, if you try Windows NT 3.51 for PowerPC, you get this:
But on NT4, you continue unharmed:
A sign I needed to hack my filesystem of bits of NT installer bits a bit more:
But, on my next try:
Well… looks like there’s an instruction that needs to be emulated (and there’s no code to currently do that). Mind you… this is decently far into booting before we hit anything fatal, which is a pretty impressive effort – and it is tempting to continue and see if it’ll run on real hardware and if it could be made to work well enough to not find any disks :)
For reasons that should escape everybody, I went back and looked at some old Operating Systems a little while ago: OS/2 Warp, Windows 3.11 and Microsoft Chicago. So, I went on a little adventure this weekend, largely in failure though.
Windows NT 3.51
This was the first version (err… no, second I think) of Windows NT that I ever used.
Lesson 1: qemu doesn’t expose a SCSI adapter that isn’t virtio-scsi (and I have a feeling there aren’t Windows NT 3.51 installer driver floppies for virtio-scsi)
Lesson 2: OMG I’m so glad I don’t have to wait for things to be read off floppy disks anymore:
Lesson 3: I’d forgotten that the Windows directory on NT 3.51 was different to every other Windows NT version, being \WINNT35
Lesson 3: Yeah, sometimes there’s just fail.
Windows NT 4.0
This brought the UI of Windows 95 to Windows NT. It was a thing. It required a fairly beefy PC for the day, but it could use two CPUs if you were that amazingly rich (dual Pentium Pro was a thing)
Lesson 1: Windows NT 4 does not like 8GB disks. My idea of “creating a small disk for a VM for an old OS as it probably won’t work well with a 20GB disk” needs to be adjusted. I’m writing this on a system with 8 times more RAM than what I ended up using for a disk for Windows NT 4.
But hey, back to \WINNT rather than \WINNT35 or \WINDOWS
Lesson 2: Sometimes, full system emulation turns out to be a better idea:
Lesson 3: Remember when Windows couldn’t actually format NTFS in the installer and it installed to FAT and then converted to NTFS? No? Well, aren’t you lucky.
Apple Rhapsody DR2
Before there was MacOS X, there was a project called Rhapsody. This was to take NeXTStep (from NeXT, which Apple bought to get both NeXTStep and Steve Jobs as every internal “let’s replace the aging MacOS” project had utterly failed for the past ten years). Rhapsody was not going to be backwards compatible until everybody said that was a terrible idea and the Blue Box was added (known as Classic) – basically, a para-virtualized VM running the old MacOS 9.
Anyway, for the first two developer releases, it was also available on x86 (not just PowerPC). This was probably because a PowerPC port to Macs was a lot newer than the x86 port.
So, I dusted off the (virtual) Boot and Driver floppies and fired up qemu…..
Yeah, MacOS X got a better installer…
Hopeful!
This was after I decided that using KVM was a bad Idea:
Nope… and this is where we stop. There seems to be some issue with ATA drivers? I honestly can’t be bothered to debug it (although… for the PowerPC version… maybe).
MacOS 9.2
Well.. this goes a lot better now thanks to a whole bunch of patches hitting upstream Qemu recently (thanks Ben!)
Yeah, I was kind of tempted to set up Outlook Express to read my email…. But running MacOS 9 was way too successful, so I had to stop there :)
and I’m off! (yes, this is the very latest qemu and skiboot):
Yes, prephv does clear all thirty two megabytes of guest memory
A quick diversion, if you try Windows NT 3.51 for PowerPC, you get this:
A sign I needed to hack my filesystem of bits of NT installer bits a bit more:
But, on my next try:
Well… looks like there’s an instruction that needs to be emulated (and there’s no code to currently do that). Mind you… this is decently far into booting before we hit anything fatal, which is a pretty impressive effort – and it is tempting to continue and see if it’ll run on real hardware and if it could be made to work well enough to not find any disks :)
