RS/6000 7043-140 boot floppies

[Tomasz Rola]

On Mon, Feb 18, 2019 at 09:49:30AM -0800, Alan Perry via cctech wrote:
> 
> Is there some trick to making boot floppies for the RS/6000 7043-140
> (a mid-90s PReP architecture machine)?
> 
[...]
> The NetBSD boot floppy images are confusing to me. The files are too
> large to fit on a 1.44M floppy. I didn't see instructions on how to
> make boot floppies out of the .fs files one can download in the
> install instructions. I went ahead and tried to dd the part that
> fits onto a 1.44M floppy and try to boot that and of course that
> failed. I have e-mailed the NetBSD prep mailing list and no response
> from that.
> 
> The system does boot the AIX install on one of its hard disks, but
> this is a recycled system and I don't have usernames/passwords for
> that install.
> 
> Does anyone here have a suggestion on how to proceed?

I have not much of idea about RS6000 but had a peek around netbsd.org
and they have page about running NetBSD on emulators of various
kind. So you may want to experiment with prep emulator, which seems to
be GXemul:

http://www.NetBSD.org/ports/emulators.html

http://www.NetBSD.org/ports/emulators.html#gxemul

and, for example, see if said floppy images boot at all.

A casual check of generic.fs gives me this:

=>  (591 12):   curl -O 'https://cdn.NetBSD.org/pub/NetBSD/NetBSD-8.0/prep/installation/floppy/generic.fs'
  % Total    % Received % Xferd  Average Speed   Time    Time     Time   Current
                                 Dload  Upload   Total   Spent    Left
                                 Speed
100 2597k  100 2597k    0     0  3251k      0 --:--:-- --:--:-- --:--:-- 3588k

=>  (591 13):    file generic.fs
generic.fs: x86 boot sector; partition 1: ID=0x41, active, starthead
0, startsector 0, 2879 sectors, code offset 0x0
You have new mail in /var/mail/tomek

=>  (591 14):   fdisk -l generic.fs

Disk generic.fs: 2 MB, 2659840 bytes
2 heads, 18 sectors/track, 144 cylinders, total 5195 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

     Device Boot      Start         End      Blocks   Id  System
generic.fs1   *           0        2878        1439+  41  PPC PReP Boot


-- 
Regards,
Tomasz Rola

--
** A C programmer asked whether computer had Buddha's nature.      **
** As the answer, master did "rm -rif" on the programmer's home    **
** directory. And then the C programmer became enlightened...      **
**                                                                 **
** Tomasz Rola          mailto:tomasz_rola at bigfoot.com             **