Saturday, February 4, 2017

PReP IBM 40p Emulation in qemu-system-ppc

Hervé Poussineau is doing a great job on improving PReP emulation in qemu. The initial patch series is getting merged into upstream master, but there is more in Hervé's git tree: I've built an OpenFirmware binary with SCSI support for it, and once Hervé improves S3 Trio emulation there will be a build with S3 support too.

Btw, the S3 Trio support in the Herve's branch is already pretty cool. Here are some screen shots of the boot process with the proprietary IBM firmware (it's really just the firmware, not an OS):

40p screen right after the reset

Other than IBM PC, an IBM PReP machine starts in a graphic mode with some animation, showing the initialization process.

Initializing devices

More devices...

All devices are found

Now the firmware tries to boot an OS or a System Management Services (SMS) disk:

F4 was pressed

Now there is a hidden but a well known feature. Instead of inserting a floppy, blindly type "eatabug", no quotes. For a tech person it may sound like "Enhanced ATA Bug", but I guess the pronunciation is "eat a bug". And this will open a resident monitor, which looks quite powerful (I still think OFW is more powerful though ;-).

Resident monitor help
 That's all about the 40p emulation for today.

/Stay tuned