Path: utzoo!attcan!uunet!mailrus!iuvax!rutgers!psuvax1!psuvm!cunyvm!ndsuvm1.bitnet!nu156266
From: NU156266@NDSUVM1.BITNET
Newsgroups: comp.sys.apple
Subject: Re: DOS 3.3 question
Message-ID: <3750NU156266@NDSUVM1>
Date: 21 Mar 90 23:34:43 GMT
References: <1441@mountn.dec.com> <15800100@ux1.cso.uiuc.edu>
Organization: North Dakota Higher Education Computer Network, Fargo, ND
Lines: 42
DISCLAIMER: Author bears full responsibility for contents of this article.

Another method to change your bootfile program name BEFORE init'ing your
disk is to do the following...

]POKE 40514,XX

If XX = 52, DOS will attempt to BRUN the startup file, if XX = 20, DOS
will attempt to EXEC the startup file.

Now... type

]INIT <FILENAME>

Now - take your favorite copy program out (FID if nothing else is handy)...
and copy over your BIN or TXT file that you want to be started first
and replace the original file (DOS will always place the current Applesoft
program in memory as the startup file).

Another method, though messier, if you're good with a sector editor, and
don't want to start formatting other disks, is to make your changes directly
to the DOS on the disk.  Note that this will only work for sure with
unmodified versions of DOS 3.3, and is not guaranteed to work with Beagle
Bros. ProntoDOS or any other of the mutant DOS that were marketed.

The boot filename will be found on track $01, sector $09, starting at
byte $75.  Note that these addresses are in Hex - and the filename extends
for 30 characters I believe.

The DOS command that will be executed on the startup filename will be found
at track $00, sector $0D, byte $42.  The values to be found there are
$06 - RUN  the startup file
$34 - BRUN the startup file
$14 - EXEC the startup file

That should do it.  I believe this same procedure MIGHT work for ProntoDOS
(you'd have to look at location $9E42 on a normal ProntoDOS disk and make
sure that value is equal to $06 for a normal BAS start file) - but the
filename to be started is found in some other place.  Send E-mail and I'll
get back to all on that.

Sorry about all the technical-ness of this - not to mention the length...

Becky...  nu156266 @ ndsuvm1