[Simh] Adding storage to vax running 4.3BSD

[Clem Cole]

On Thu, May 11, 2017 at 4:37 PM, Johnny Billquist <bqt at softjar.se> wrote:

> True. However, it isn't actually the geometry that cause the Unix messup
> here, but the fact that Unix divided disks into partitions. So it needed to
> know where each partition started. And before disklabels, it was hardcoded
> per disk type.

​To be fair....


UNIX partition the RP06 because it overflowed a 16bit integer on the
PDP-11.    The 36 bits machines DEC was making at the same time did have
that problem.    Because UNIX supported mounted file systems which most
small computer systems could not, ​it was a fairly elegant solution.

Like many software tricks that were introduced to solve one issue, it was a
handy solution for others and partitions became de rigor for quotas,
organization and other sins.   The commercial UNIX vendors put labels and
support in the disk ROMS pretty early, (PC/UNIX's was ham strung by the
sins of IBM) but its a classic example of things are the way there are
because it made a lot of sense when it was done.   Time moved on....

And as Paul and I were discussing off-line 'support' for MSCP really was
not a 'mess-up' -- it was a zip/zag where DEC went one direction and by
that time it came out, BSD was trying to solve a problem different than
what DEC's cared about and non-DEC UNIX vendors started having their own
solution.

So while its an example of the start of DEC HW being to quit being the
'focus' for things UNIX.  It was a cool new thing DEC had, but basically it
was minimally supported, not exploited, because people did not care at the
point.

Clem

Clem
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