[rescue] AT&T 3B2 revival

Sandwich Maker adh at an.bradford.ma.us
Tue Aug 18 20:09:18 CDT 2015

" From: Alan Hightower <alan at alanlee.org>
" On 2015-08-18 18:45, adh at an.bradford.ma.us wrote: 
" > remember, the 3b architecture was developed for the controller of the
" > 3ess, and telephone switchgear lasts a *looong* time; we designed for
" > 20-year 24x7 uptime. the 4ess, also using a 3b20d main controller,
" > was made from '76 to '99, and there are still some 100 in service,
" > with plans for a next-gen 4ess. the 5ess, still in production, has a
" > 3b21d 'administrative module'.
" > 
" > the 3b20d and 3b21d are, in telcom style, completely double-redundant;
" > you can walk up to one and pull any board at random without affecting
" > operation. they, and their relevant intellectual property, won't be
" > obsolete any time soon.
" I thought most of the current 3B2 lineage (4E/5E) was done in emulation
" on Sun machines? I'm a bit surprised at the notion of a WE32200 in
" silicon running in 2015. 

that may be true of the 3b2 per se, but that was just an
implementation of the 3b20 arch in lsi [the '20 was ttl].  and the lsi
versions never had the telco-reliability-level of machines that can be
fixed while running.  for that, you need the full redundancy of the
'bigger' members.

suns don't have that reliability.  i think an emulation would be even
less reliable.

nb. the 3b21 is a '95-era machine; it may well be lsi instead of ttl.
even a gate array implementation would probably be a speed/power

ps. my first unix login was on a 3b20, running sVr0.  iirc it was
about half the speed of a vax 780.  my first formal unix admin was on
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen
adh at an.bradford.ma.us                       and think what none thought

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