Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!apple!bbn!bbn.com!slackey
From: slackey@bbn.com (Stan Lackey)
Newsgroups: comp.sys.atari.8bit
Subject: More on SIO
Message-ID: <38936@bbn.COM>
Date: 20 Apr 89 21:45:14 GMT
Sender: news@bbn.COM
Reply-To: slackey@BBN.COM (Stan Lackey)
Organization: Bolt Beranek and Newman Inc., Cambridge MA
Lines: 30

OK, I just KNOW there are many many of you out there who are just dying
for an update on my PC-DOS-to-Atari disk file transfer progress...

The way I left it was I could read 810 and 1050 format disks OK, but was
unable to read XF551 (DD) disks at all.  Well, part of the problem is
fixed, that is I can read Atari-formatted DD disks now.  Apparently what
had happened was I had put the XF551 into some bogus state by attempting
to read the PC-written disk, and then attempting to read sectors 1,2,3 
of an Atari disk (which, by the way, Atari keeps in SD.  Question 1.
Is that done by software in the computer, or by the drive itself?)

As I recall, when I used Spartados DSDD XF551, it seems those sectors
may have been formatted DD because it took a couple "tries" before
a DD would boot.  Question 2. Does anybody know?

Finally.  I still can't read PC-DOS disks.  Are they in 256-byte sectors?
Is there some other incompatibility that will stop me?  How do I find
out?

Why not...  Is there more up-to-date information available from Atari,
later than the tech notes?  Specifically on DOSXE and/or the XF551?

Oh - I had noticed in the DOSXE book that disk files can have holes in them,
that is, NOTE/POINT don't have to add on to the end of a file.  I read on
to see how this works, and found that the file format includes a sector
map, apparently to allow NOTE/POINT to work even when a file is copied.
(The NOTE/POINT implementation is incompatible with DOS2, which actually
uses physical sector numbers.)  I thought this was really neat!  Do other 
DOS's have this feature?  Just curious.
Thanks, your help is appreciated.  -Stan