Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!rutgers!cbmvax!jesup
From: jesup@cbmvax.UUCP (Randell Jesup)
Newsgroups: comp.sys.amiga.tech
Subject: Re: faster dos reads
Keywords: DOS, slow, real slow, deadly slow
Message-ID: <6019@cbmvax.UUCP>
Date: 20 Feb 89 23:40:13 GMT
References: <3699@ucdavis.ucdavis.edu>
Reply-To: jesup@cbmvax.UUCP (Randell Jesup)
Distribution: comp.sys.amiga.tech
Organization: Commodore Technology, West Chester, PA
Lines: 36

In article <3699@ucdavis.ucdavis.edu> u563694848ea@deneb.ucdavis.edu (Bruce Rogers) writes:
>
>	Hi, I'm looking for some information on speeding up normal
>AmigaDos reads. I've tried numerous different methods and these are the
>numbers I've gotten:
>
>200K files read:
>
>Aztec fread: 22 secs
>Aztec fgetc: 14 secs
>AmiDos Read:  9 secs
>load program (to run) 4 secs!

	Watch out: buffering can make reads appear to be faster than they
are.

	If it loads (to run) from disk, not buffers, in 4 seconds, it must
be off a hard disk (the theoretical max speed of trackdisk is 20K/sec,
filesystem is slower).

	The reason your load is slower than LoadSeg() is probably buffer
sizes (your read buffer).  If you make 400 512byte requests from a hard disk,
it's a lot slower than 1 200K request.  LoadSeg() tries to use as large reads
as it can, given the structure of the file.

>	If I can't find a way to get the loading down in the 5-10
>second range, I will probably try using the trackdisk device. Can anyone
>tell me how fast I can expect that to go?

	Don't do it unless you absolutely must.  With a harddisk, you
REALLY don't need/want to be mucking with the trackdisk-level interface.
Even with floppies, it's inadvisable - for example, if we make any changes to
the layout the FS puts on the disk in 1.4, you'll break horribly.

-- 
Randell Jesup, Commodore Engineering {uunet|rutgers|allegra}!cbmvax!jesup