> [VS4000 vs 11/780]
> And a lot harder to repair...
Although I've seen it done remotely on this very
list for
either a VLS or a VS4000-60. Perhaps 780s just don't break :-)
Realistically 11/780's are now of an age that contact reliability
for all those cards is the biggest issue.
4000-60's aren't spring chickens either but they have a lot fewer
components and way way fewer sockets/contacts.
I've done component-level repair on both 11/780 systems and 4000-60
systems but it was always at the line-driver/memory chip level,
i.e. parts that are very easy to isolate and diagnose often through
the very process of swapping out stuff at the board-level.
VAX6000 systems are probably the ultimate in over-engineering for
reliability and although they've got a lot fewer boards than a 11/780
they still have some BI-bus contact reliability issues despite a
much slicker edge connector and less age.
Tim.