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From: dillon@CORY (Matt Dillon)
Newsgroups: net.micro.amiga
Subject: Disk Buffering
Message-ID: <8610020745.AA09153@cory.Berkeley.EDU>
Date: Thu, 2-Oct-86 03:45:04 EDT
Article-I.D.: cory.8610020745.AA09153
Posted: Thu Oct  2 03:45:04 1986
Date-Received: Sat, 4-Oct-86 05:19:13 EDT
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Organization: University of California at Berkeley
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This isn't a flame, but what I hope is some constructive criticism of the
amiga's current disk buffering scheme:

			It's pretty well useless.

Where it fails:

	(1) JOIN happens to be unbuffered. Thus if you JOIN two large files
	on a disk and the destination is the same disk, the drive seeks
	every 512 bytes (or abouts) and takes FOREVER to do the operation.

	(2) Two processes trying to read the disk, or one reading and one
	writing (etc...) causes excessive seeks. (about one every 512
	bytes.. that's BAD)

	(3) Run'ing one command in the background and while it's loading
	trying to execute another command. (same as (2)).

The point: Sector caching fails when your reading sequential files

The solution:	One track buffer isn't enough.  Why not make it configurable?
Even better, you can have both sector caching and N (2+) track buffers 
(just make sure you aren't sector caching anything in the track buffer).
I realize that track buffers cost in memory, but then, that's why you make
it configurable.

This would solve a great many problems, the least of which being that we
would then be able to use Multi-Tasking efficiently with DOS.

				Ya? It isn't even fancy.

				-Matt