Path: utzoo!attcan!uunet!wuarchive!usc!jarthur!uci-ics!baxter
From: baxter@ics.uci.edu (Ira Baxter)
Newsgroups: comp.unix.i386
Subject: Re: ESDI caching disk controllers: Reprise
Keywords: ESDI cache
Message-ID: <263E613E.23840@paris.ics.uci.edu>
Date: 2 May 90 04:25:34 GMT
References: <274@caslon.cs.arizona.edu> <873@sixhub.UUCP> <1424@ssbn.WLK.COM> <1736@serene.UUCP>
Distribution: na
Lines: 15

In article <1424@ssbn.WLK.COM> bill@ssbn.WLK.COM (Bill Kennedy) writes:

> With a 768K cache memory on one card I routinely get 32% cache hits
> and with 4Mb on the one in ssbn I get 48-52% cache hits.

I have never understood this.  If a caching disk controller with 4Mb gives
you a high hit rate, why not put the 4Mb of RAM into your CPU, and
let UNIX use it as a cache?  The hit rate should be the same.
The win is that the OS should be able to divide the RAM between disk
cache and process space (I assume UNIX isn't brain-dead in this regard?).
Then you have the best of both worlds.

Or am I missing something?
--
Ira Baxter