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From: bb@tetons.UUCP (Bob Blau)
Newsgroups: comp.arch
Subject: Re: RISC as a "technology window"?
Summary: TANSTAAFL
Message-ID: <759@tetons.UUCP>
Date: 30 Mar 89 18:39:26 GMT
References: <1552@vicom.COM> <15690@cup.portal.com> <1562@vicom.COM> <16181@gumby.mips.COM>
Organization: Amdahl Corp., Rexburg, ID
Lines: 25

In article <16181@gumby.mips.COM>, keith@mips.COM (Keith Garrett) writes:
: In article <6416@cbmvax.UUCP> jesup@cbmvax.UUCP (Randell Jesup) writes:
: >
: >	The problem with this is that off-chip access is slower than on-chip,
: >due to signal load and pad static-protection capacitance.
: 
: there are also serious speed-of-light considerations. ...
: ...  this effect will become worse in
: the future as transistor speeds become faster ...

This may be true in the far future when everything is optically
interconnected (on and off chip.) Today, at very high speeds, on-chip 
delays rise up to bite you too!
Cray can achieve very fast cycle times with low levels of integration
and clever packaging - putting everything on-chip is not a panacea.

Apply: Std. disclaimer

Remember - it is possible for a particle to go faster than the speed
of light, just not in a vacuum!

-- 
  Bob Blau       Amdahl Corporation    143 N. 2 E., Rexburg, Idaho 83440
  UUCP:{ames,decwrl,sun,uunet}!amdahl!tetons!bb           (208) 356-8915
  INTERNET: bb@tetons.idaho.amdahl.com