Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!lll-winken!uunet!microsoft!w-colinp
From: w-colinp@microsoft.UUCP (Colin Plumb)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Floppy speed.
Message-ID: <67@microsoft.UUCP>
Date: 25 Mar 89 17:53:28 GMT
References: <9853@polyslo.CalPoly.EDU>
Reply-To: w-colinp@microsoft.uucp (Colin Plumb)
Distribution: na
Organization: very little
Lines: 25

cknight@polyslo.CalPoly.EDU (King Claudius) wrote:
> What is the speed of the standard 3.5" Amiga drive in bytes per second?
> 
> And secondly, if anyone knows, what is the speed of the Atari ST 3.5" drive
> in bytes per second (their drives are supposed to be the fastest; God
> knows their the noisiest).

Assuming both spin at 300 RPM, both take 0.2 seconds to read a track.
Because the Atari puts 9x512=4608 bytes on a track, that's 23040 bytes
per second.  The Amiga puts 11x512=5632 bytes on a track (11x(512+16)=5808
bytes if you cheat a bit), you get 28160 (29040) bytes per second.

I am assuming the Arari is smart enough to start reading whole tracks
with the first sector it finds, instead of waiting for sector 1.  If
it isn't, reduce that figure by 1/3 (to 15360 bytes/sec) to allow for
the additional 1/2 track (0.1 sec) average latency.  The Amiga never
waits to start reading.

There is the point that the Amiga always reads full tracks (0.2 sec) while
to read just one sector, the Atari has an average 1/2 track latency.  So
for a point read, the Atari is faster.  For bulk reads, the Amiga wins.
-- 
	-Colin (uunet!microsoft!w-colinp)

"Don't listen to me.  I never do." - The Doctor