Article View: comp.sys.amiga.tech
Article #11531Re: faster dos reads
From: Randell Jesup
Date: Mon, 20 Feb 1989 23:40
Date: Mon, 20 Feb 1989 23:40
36 lines
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1923 bytes
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
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Path: arc1-ca.pugleaf.net!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