A while ago, I found this site http://vetusware.com/ with abandonware.
Bits and bytes, forgotten, lost in history. Among the files on this site,
there is Xenix. A UNIX-os, back in the days, by Microsoft.

Long forgotten times, times, when computers were still interesting
(and I was still wearing diapers)

Afin…. monday, this Xenix OS was broad up in a conversation
at Stack, and so, I decided to try to get the damn thing working.

Not as easy as it looks like, to get the Xenix version for the 8086
working. Even though, modern x86 hardware is supposed to be
compatible with the original IBM-PC, none of the emulators seems
to understand what to do when I feed it the disk images.

One of the reasons, perhaps, is the fact the floppy images are
360k images, and the emulators only understand 1,44 MB images.

I have tried virtualbox, qemu, bochs and PCem, without luck.
PCem, well… it’s a windows app, but it runs in wine. PCem
seems to emulate older, real hardware, or tries to. It supports
various machines, and BIOS files from the original hardware.

It also includes AMI 386 and AMI 486 with BIOS files….
Oh… memories… seeing the AMIBIOS again, the way it
used to look on my first computer…. but booting Xenix….
no, that’s too much to ask….

Some note to make, as it seems, the boot loaders do
load in some of these emulators, but the boot loader
seems unable to load the kernel. The kernel file is
available on the floppy image

To mount such an image, use

mount N1 test -o loop -t sysv

For one part, I suspect these old images possibly do not
respect the boot signature, and therefore mark the image
as non-bootable. And for the part the boot-loader does
work, I suspect the emulation of the floppy controller is
not completely accurate, as in, possible timing issues.
But this is just a wild guess….

Anyways…. I have found an emulator that passes this
point, and boots the kernel correctly. The emulator that
works is an emulator specific for the IBM PC 5150,
and that seems to do the trick…. but now…. I have to
find out how to swap the disk image to insert the 2nd
disk when Xenix asks for it.

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