[Qemu-devel] [TUHS & QEMU] Making progress with old DG/UX virtualization. Need advice.

[Natalia Portillo]

Hi,

I've read all your posts in the QEMU mailing list and the TUHS one and I'm 
answering to both lists in a hope my mail enlights you and any other curious.

First of all, old UNIX systems (and I put my hand on the fire for DG/UX also), 
use a monolithic linked at setup/later time kernel.
That is, even if you get a driver (IDE, virtio, whatsoever), the configuration 
files, the kernel, the ramdisk, everything that lets your system boot, MUST 
HAVE BEEN BOOT from the AIC controller, the driver is hardcoded, no way to 
change it.

If you have extensive knowledge of what files a driver setup modifies on DG/UX 
specifically (knowledge from other UNIX, forget it, they are as different as 
Porsche and Ferrari motors), you can always get a new kernel with the drivers 
you need to make it boot and manually put them in your image.

In the case, you meet this requirements, and, you do it, you can then achieve 
to other problems. The DG/UX workstations are x86 machines, but nothing swears 
they are PC compatible machines, and they can have a different memory map for 
some critical device, or include critical devices never found in a PC (like an 
Intel Macintosh does for example). Just booting from a BIOS doesn't make the 
machines be the same (PowerPC Macintosh, IBM POWER workstations, Genesi 
Pegasos, are machines that boot OpenFirmware with heavily different 
configurations, devices and memory maps).

Also, you are assuming IDE is available in DG/UX just because the controller is 
present in the hardware. That hardware was also used for Windows NT. IDE 
support can be JUST FOR Windows, and the DG/UX manufacturer just decided to not 
include an IDE driver in the kernel (happened in AIX for PCs until last version 
of all, only SCSI was supported, being a hugely strange controller in PC 
worlds).

In the case you opt for making a driver (adding IDE, virtio, or other SCSI 
support) for the DG/UX need to say you need, low level knowledge of the 
hardware, low level knowledge of the operating system, a working machine (for 
sure, with the hardware available), a debug machine (almost sure also), C and 
maybe assembler knowledge. In a scale of 10, this puts the difficulty in 8 for 
most of programmers, and surely if you were one you stacked with the first 
option everyone gave you (see next sentence).

The easiest way, and the one that people answered you already in QEMU's mailing 
list (in a scale of 10 the difficulty is 6 or even 5), is creating an emulated 
device (that's the correct term, not "driver") for an emulator, like QEMU, 
Bochs, VirtualBox (forget this option for VMWare, VirtualPC or Parallels) that 
adds the AIC SCSI controller you exactly need.

Why is this easiest? You don't need any DG/UX working system, you don't need to 
know how DG/UX works, you don't need to compile a kernel, copy it to your image.

You just take the Adaptec's documentation, and start coding, making a SCSI 
emulated controller, and testing it with systems you can always reinstall, 
debug, and check, until they fully work (Windows, Linux, BSD, take your choice).

And then, you just polish it until your DG/UX boots, or finds the memory map as 
a mess it doesnt like.

Finally, please stop begging on all the internet, spend that time coding the 
driver or getting the money to pay a programmer that will do.

Sincerely yours,
Natalia Portillo
Claunia.com CEO
QEMU's Official OS Support List maintainer