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From: csrobe@ICASE.ARPA (Charles S. Roberson)
Newsgroups: comp.sys.atari.st
Subject: RE: fast multi-sector floppy I/O with interrupts (question)
Message-ID: <8707211217.AA01889@work1.icase>
Date: Tue, 21-Jul-87 08:17:00 EDT
Article-I.D.: work1.8707211217.AA01889
Posted: Tue Jul 21 08:17:00 1987
Date-Received: Wed, 22-Jul-87 07:22:53 EDT
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>From: mcvax!philmds!nlgvax!johan@seismo.css.gov  (Johan Stevenson)
>Subject: fast multi-sector floppy I/O with interrupts (question)
>To: info-atari16@score.stanford.edu

>To speed up I see the following options:
>
> - improve the driver, so that the interrupt caused by the first sector
>   is in time to start the transfer of the second sector
>
> - use a non-standard floppy disk formatter that gives physically
>   consecutive sectors the following relative sector numbers:
>	1, 6, 2, 7, 3, 8, 4, 9, 5
>
> - perform the same trick as above in the driver itself

Alert Box, pg. 8, STart, The ST Quarterly, Summer 87, Volume 2, Number 1
	"Last issue, START presented several hard and floppy disk
	utilities by David Small and Dan Moore.  One of these was
	Twister, a program enabling you to add another 40K per side
	of your standard 3.5 inch ST disks.  Atari has even decided
	to adopt the Twister format, starting with the new TOS ROMS
	that will be available soon....".

I wish I had remembered to bring in the Winter/Spring issue (Vol 1, No. 4)
so I could see if the Twister format is the same as yours
(1,6,2,7,3,8,4,9,5).  Maybe tomorrow.

NB:  If anyone is using version of Twister that came out in that last
issue (Vol 1. No. 4), you should make a change in the source.  "The
code on your last START disk will place the same serial number on
each disk when you format the disk in Twister format.  This causes
your ST operating system to get confused..."  David Small had
"inadvertantly used a 'serial number' parameter of -1 in the Protobt()
call." When START tried to make a last minute change, they changed
the -1 to 1,000,000L.  

	"To correct it, change the value [1000000L] to 0x1000000L"

-chip
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Chip Roberson                ARPANET:  csrobe@icase.arpa
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