Hardware Architectures and I/O (was: Re: Jargon file...) **FLAME!!**

[Bill Stewart 908-949-0705 erebus.att.com!wcs]

In article <1990Dec2.154303.17105 at eddie.mit.edu>, rs at eddie.mit.edu (Robert E. Seastrom) writes:
> RS-6000s also have an annoying tendency to "lock
> up" for a few seconds (5 < x < 15) and then return to normal - I'm
> told that this is normal and due to paging activity.  

AAARGH!  My VAX 11/780 used to behave in this pathological manner,
which is much more annoying when you have a dozen people doing vi
than one person.  We were trying to do a 12MB process on a 4MB VAX,
and had used 4.1BSD for a while.  We got about the third copy of
VAX Paging SVR2 to leave Summit - it wasn't a beta copy (which
implies support), it was just a favor (thanks, Doris!)

VAX OS's were somewhat flaky then because of the brain-damaged DEC
UDA-50 disk controllers and suicidal-to-install DEC patchware,
and our machine had a giMongous amount of memory compared to the
average VAX or 3B2 of its day.  Since our major application
(a simulation which spent most of its time thrashing memory) was
radically different from Summit's intended applications (vi/troff/cc
with maybe a few 1/2MB user programs), their tuning advice for "big"
systems only made things worse.  Eventually, by doing the opposite
of what they said, and using a VERY large swap area on disk,
we were able to get a livable system.

After a year or two, the price of memory finally came down to the
point that we could afford 16MB (about $50K).  RAM really is 100
times faster than disk :-)
-- 
				Pray for peace!
					Bill
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# Bill Stewart 908-949-0705 erebus.att.com!wcs AT&T Bell Labs 4M-312 Holmdel NJ