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RE: installboot is broken
On Sunday, March 24, 2013 at 1:51 PM, Anders Magnusson wrote:
> On 03/24/2013 08:08 PM, Mark Pizzolato - Info Comm wrote:
> > This issue CAN and SHOULD be fixed. However, there is a fundamental
> > chicken and egg problem here in that every available NetBSD vax ISO image
> > going back to the earliest available (NetBSD 1.6.2) are all missing this
> > boot
> > block on that media. Clearly no one has attempted to install any version of
> > NetBSD on a legacy VAX (one which boots without the aid of a ROM based
> > VMB).
> I have done that on all of them; since I actually wrote the code :-)
Something has broken since then or you really never installed from a CD. These
systems generally didn't have CD drives...
> > This issue came to light due to efforts to use NetBSD with the latest simh's
> > new VAX simulators (VAX 11/730, VAX 11/750 and VAX 8600/8650). All of
> > these systems use VMB to initiate the bootstrap process and since the disk
> > being booted doesn't contain a Digitial ODS2 disk structure, they boot using
> > they achieve a boot using the bootstrap code provide in sector 0 of the
> > device being booted. The systems with ROM based VMB have built in code
> > in the ROM VMB to use the pointers describing the bootstrap location in
> > sector 0 to directly load the rest of the bootstrap (usually from sectors 1
> > thru
> > 13) and dispatch to that.
> You are not supposed to use VMB on those big machines. You should load
> boot directly from the console media.
> This is how all BSDs always have worked.
I guess that might be possible (even on a VAX 11/750, you could always boot
thru the console TU58). Given hard booting a dedicated loader program the
details of the boot block won't matter. However, you'd still have to make the
TU58 media bootable. The 750 Boot procedure (for any device) loads sector 0
and starts execution at offset 2 of the 512 bytes loaded. There current isn't
any code in sector 0.
Many systems I came into contact with from the early 80's onward (mostly 750's
then) booted BSD OSes directly from disk, No console media in the picture.
Likewise, as Johnny mentioned, Ultrix has always booted directly from the
target media using a 'Boot Block' boot.
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