Path: utzoo!mnetor!uunet!husc6!cmcl2!nrl-cmf!ames!oliveb!sun!joe!petolino
From: petolino%joe@Sun.COM (Joe Petolino)
Newsgroups: comp.arch
Subject: Re: Performance increase - a suggestion (really sequent cache)
Message-ID: <39245@sun.uucp>
Date: 19 Jan 88 04:40:09 GMT
References: <235@unicom.UUCP> <8844@steinmetz.steinmetz.UUCP> <262@tmsoft.UUCP>
Sender: news@sun.uucp
Reply-To: petolino@sun.UUCP (Joe Petolino)
Organization: Sun Microsystems, Mountain View
Lines: 24

> [ description of ownership protocol for cache coherence ]
>
>  I think this is a particularly elegant solution to the cache
>coherency problem.  Does anyone know if Sequent invented it (seems
>rather too obvious for that), or a proper reference to who did? 

Amdahl was designing systems like this almost ten years ago (all of the
580-series processors use ownership schemes).  Note that cache consistency
can be a problem even in single-processor systems, if Virtual aliases are
allowed in a virtually-addressed cache.

The earliest references I could find by digging through my old Alan Jay Smith
papers are:

   C.K. Tang, "Cache System Design in the Tightly Coupled Multiprocessor
   System", Proc. NCC, 1976.

   Lucien Censier and Paul Feautrier, "A New Solution to Coherence Problems
   in Multicache Systems", IEEETC, C-27, 12, Dec 1978.

I have no idea whether either of these papers actually describes an ownership
protocol.

-Joe