Path: utzoo!utgpu!water!watmath!clyde!rutgers!rochester!bbn!uwmcsd1!gmwi1!marque!gryphon!richard
From: richard@gryphon.CTS.COM (Richard Sexton)
Newsgroups: comp.sys.amiga
Subject: Re: AmigaDos don't thrash no more!
Message-ID: <2541@gryphon.CTS.COM>
Date: 13 Feb 88 05:05:59 GMT
References: <8504@sunybcs.UUCP>
Reply-To: richard@gryphon.CTS.COM (Richard Sexton)
Organization: Trailing Edge Technology, Redondo Beach, CA
Lines: 29

In article <8504@sunybcs.UUCP> ugpete@sunybcs.UUCP (Peter Theobald) writes:
>
>AmigaDos should sort disk requests by track. This way if three processes
>ask for three different files scattered all over the disk, instead of
>jumping around like a Tasmianian Devil getting blocks from first one
>file, then the other then back to the first, AmigaDos would load in the
>blocks on the tracks currently nearest the read head. Then it would move
>the head to the next track with requested data on it, etc... It could
>continue this process sweeping the head back and forth across the disk
>picking up what is needed, wasting the least amount of time.
>	This would eliminate thrashing, and would speed up disk accesses
>to boot! I think this is similar to what a clone of Peter da Silva meant by
>single-threading loadSegs.
>	How major a change in AmigaDog is this?
>

This may not be as much of a gain as it would seem on first impression.

I've seen quite a few cases where two processes were getting lots
of tracks from opposing ends of the disk.

It's horrible.



-- 
                "He tried to do his best, but he could not"           
                          richard@gryphon.CTS.COM 
   {ihnp4!scgvaxd!cadovax, rutgers!marque, codas!ddsw1} gryphon!richard