Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!pt.cs.cmu.edu!rochester!rit!cci632!tvf
From: tvf@cci632.UUCP (Tom Frauenhofer)
Newsgroups: comp.realtime
Subject: Re: Lightweight Tasks
Message-ID: <29911@cci632.UUCP>
Date: 28 Jul 89 01:52:32 GMT
References: <2153@gmu90x.UUCP> <129300004@p.cs.uiuc.edu>
Reply-To: tvf@ccird7.UUCP (Tom Frauenhofer)
Organization: CCI, Communications Systems Division, Rochester, NY
Lines: 29

In article <129300004@p.cs.uiuc.edu> gillies@p.cs.uiuc.edu writes:
>
>Lightweight is to tasking as RISC is to computer architecture.

Uh-oh.  I smell trouble afoot. ( :-) )

>RISC was a knee-jerk reaction to the hideous complexity of
>the VAX; Lightweight tasks were a reaction to the hideous slowness of
>UNIX tasking.

A couple of points:

1)	Yes, RISC was a knee-jerk reaction to the VAX.  Fortunately, we
	needed this "knee-jerk" to make us take a hard look at the
	instruction sets and processor complexity that the hardware
	architects were coming up with (unfortunately, the RISC
	proponents exaggerated the advantages of their solutions, just
	as the CISC-ers go overboard in ragging on RISC, but that's
	for another group).

2)	Lightweight threads are more than just a reaction to the
	slowness of UNIX tasking; they are, instead, a re-evaluation
	of what defines a "context".  This, to me, is the real value
	of the Lightweight/Heavyweight dialogue.

Thomas V. Frauenhofer	...!rutgers!rochester!cci632!ccird7!tvf
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