Re: VS2000 + NetBSD

[Anders Magnusson <ragge%ludd.ltu.se@localhost>]

Den 2018-04-11 kl. 19:11, skrev Holm Tiffe:
> ..that thing is going complicated.
>
> I have an VS3100 M76 with an installed NetBSD 1.5.3 on it that
> I used for Netbooting (Mopd) and I connected the fresh installed Disk to
> it and tried to boot..failed.
> Next I've netbooted the m76 and looked at the disk..all ok so far.
> I've erased the first 16 blocks from the disk, copied the first Blocks
> from the M76 disk and modified the disklable according the actuel
> filesystem sizes (VS2000 disk is smaller, only the last partition
> differs).
> With that disk the VS2000 with the modified Firmware could start the
> primary loader (sdboot) but the loader couldn't find boot or boot.vax
> the 2nd loader.
>
> I've found out that the primary loader on the M76 isn't the 1.5.3.
> sdboot since there is aoccurence of cd9660 in the code, I do hvave some
> other NetBSD Version on the disk that seems to be the source of that code,
> the xxboot from that Version written with disklabel from 1.5.3 to the
> disk makes an almost working primary bootstrap, but fails to boot the
> 2nd.
> I've tried to netboot that version, it results in an endless row of
> stray irq 18 ipl 31 on both machines. Don't know anymore what verion
> that is, think 1.6.0 or 1.6.2 or so..
>
> The begin of partition a on the disk is offset 16 blocks to the begin of
> the disk. How is the concrete layout of that 16 blocks, from where to
> where is the lable and where is the primary bootstrap?
All disks on all VAXen uses the same bootstrap code, which is located in
sectors 0-15 on the disk.  The disklabel is embedded in a bunch of code
in block 0, together with some magic numbers to make the firmware happy.

The disklabel itself is at LABELOFFSET, which is 64 bytes into block 0.

For the VS2k the boot block uses the provided ROM routines to load /boot,
so if something did not function as expected with the patched routines
the booting would fail.

-- Ragge