Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hoptoad!gnu
From: gnu@hoptoad.uucp (John Gilmore)
Newsgroups: comp.realtime
Subject: Re: Microsecond Resolution Clock for Sun Workstations Available
Message-ID: <8238@hoptoad.uucp>
Date: 7 Aug 89 06:37:58 GMT
References: <30404@ucbvax.BERKELEY.EDU>
Organization: Grasshopper Group in San Francisco
Lines: 21

> We have produced a microsecond resolution timer board for Sun workstations...

FYI, the SPARCstation-1 come standard with pair of microsecond
resolution timers as its main system clocks.  Gate arrays are wonderful
things.  (It also has a battery backup TOD clock.)  This is not to
disparage the work done to bring high resolution timing to the other
models.  (The Sun-1 and Sun-2 had an AMD timer chip whose spare timers
could be set up as a 64-bit high resolution clock, too, by the way.)

> On a 3/50 with the screen blanked...

It may surprise some people, but blanking the screen on a 3/50 speeds
it up by up to 40%, since refreshing the video from main memory burns
about 40% of the memory bandwidth.  If you have a 3/50 doing some
dedicated job, and need the cycles, attach a terminal as the
console.  Without the video overhead, it's about as fast as a 3/160.
(15 MHz 1 wait state, versus 16.67 MHz 1.5 wait states).
-- 
John Gilmore      {sun,pacbell,uunet,pyramid}!hoptoad!gnu      gnu@toad.com
      "And if there's danger don't you try to overlook it,
       Because you knew the job was dangerous when you took it"