Re: Dos 3.3 question

[shoppa@almach.caltech.edu (TIM SHOPPA)]

In article <1993Jun2.013727.84249@ns1.cc.lehigh.edu$, dg04@ns1.cc.lehigh.edu (DAVID GRUMBINE) writes...
$In article <1ug8u5$jrf@charm.magnus.acs.ohio-state.edu$, mspaeth@magnus.acs.ohio
$-state.edu (Wayne Gretzky) writes:
$$I recently dug up a stack of DOS 3.3 floppies, but they aren't recognized
$$by The finder (DOS 3.3 FST) or Copy II+ 8.3 or 9.0, and I've noticed that
$$in the catalogs, they say things like "Super Disk 254" or "John's Disk 254"
$$instead of the normal "Disk Volume 254" and that they seem to be somewhat
$$virual, in that any dos 3.3 disk I put in the drive before rebooting starts
$$giiving this message on the catalogs also...
$ 
$Sounds like these are using a "customized" version of DOS 3.3.  I think these
$were a popular way to try to copy protect things back then.  I also seem to
$remember being able to do something to them to get them to work "normaly",
$but I think I was able to break into the patched DOS and use it like normal,
$but on the messed up disks.

I remember these "customized" DOS's to be improvements on the Apple DOS.
Very often they had new commands, and changed the order in which sectors
were written to disk to speed up disk access.
Another popular one was Beagle Brother's DOS.  These were all quite compatible
with regular DOS, as I remember.  They may be somehow incompatible with
the finder, etc., however.  Some of them undoubtedly had the option to move
the track that the directory was stored on from 17 (decimal) to something
else.  I remember this being an option with Beagle Brother's DOS.  Most
people didn't do this - the catalog tracks are probably still on track 17.

$ 
$$My question is:  Does anyone remember how to make these into normal Dos 3.3
$$disks?  I used to be able to do so, but I no longer remeber how.  I thought
$$copying DOS from a clean disk (tracks $00-$02) would do it, but it didn't...
$ 

I would think this would work too!  Unless the order in which the sectors
come on the disk was modified... (see below)

$No, I think that the tracks/sectors are probably moved around physically so
$that normal DOS 3.3 (or ProDOS, etc.) won't be able to find them (except
$of course track 0 sector 0).  It seems weird that the DOS on these disks
$can actually read normal DOS 3.3 disks.  Hmmm.  Start at trask 0 sector 0
$and disassemble it??  Yeah right.  :-)

Yes, very often in these DOS's the order in which sectors were used were
changed.  This helped speed up file loading in DOS.  (There is some
modern term for this practice, called "skewing" or such.  All hard disk
drive formatting utilities let you change this "skewing" pattern to
one that gives the fastest disk performance.  It's basically a matching
between the CPU speed and the speed that sectors are read in.)

I'm not sure from the original message whether you have tried reading
the funny disks with regular DOS 3.3, or if they have only tried from
ProDOS.  I wouldn't be surprised if they were readable under 3.3 but not ProDOS
because of the sector skewing.

Did you say that the DOS on these disks can read DOS 3.3 disks?  They can
probably write DOS 3.3 disks too.  Run the old 3.3 utility FID (under the
funny DOS) and try to copy to a standard 3.3 disk.  The result may very
well work fine.

					Good luck!
					Tim (shoppa@almach.caltech.edu)