henry@utzoo.UUCP (Henry Spencer) (07/10/83)
While we're on the subject of CPU clock speeds being deliberately
slowed down, there are a couple of shining (stinking?) examples in
our own Unix backyards. Did you ever wonder why the pdp11/60, which
is quite slow except for floating-point work, has such a strangely
high model number? Apparently the production 11/60 was drastically
slowed down for marketing reasons -- the story is that the original
11/60 prototypes could and did outrun the 11/70. On a less drastic
note, I am told you can speed up an 11/23 about 20% just by replacing
the clock crystal with a faster one. While this is true of a lot of
circuitry if you are willing to accept large losses in tolerance for
voltage and temperature variations, apparently the 11/23 really is
perfectly capable of running reliably at the higher speed. Once again,
mysterious marketing considerations are the reason why DEC supplies
them with the slower crystals.
If any of the DEC folks out there want to reply, be my guest. Things
being the way they are, I naturally reserve the right to believe any
confirmations and disbelieve all denials...
--
Henry Spencer
U of Toronto
{allegra,ihnp4,linus,decvax}!utzoo!henry