kevin@voder.UUCP (The Last Bugfighter) (02/27/88)
I read something recently which points out a possibly serious problem
for some users of Atari's new XF551 disk drive. This is from an article
published in the March '88 newsletter of the Bay Area Atari Users Group
(BAAUG), I should point out that I do not own an XF551 and haven't been
able to confirm this problem but the article sounds correct.
When non-Atari users buy 5 1/4-inch floppy disks they have to purchase
either soft or hard sectored disks depending on their drive. If you look
at the disk you will see a small hole in the envelope next to the large
center hole on the side of the write-protect notch. This is the index hole.
If you now rotate the disk inside its envelope a small hole in the mag-
netic medium will appear. If the disk is soft sectored there will be one
hole, if hard sectored their will be several, usually 10 or 16 depending
on the number of hard sectors it uses. Soft sectored disks use this index
hole as the starting point for the software created sectors when formatting
a disk. Hard sectored disks use the holes to mark where each sector starts.
Atari users don't have to worry about this as neither the 810 or the 1050
drive have the LED sensor which reads this index hole(s) so they can use
any type of 5 1/4-inch floppy disk.
But the XF551 does read this index hole. If you flip the disk over, like
if you were going to write to the back side of the disk, the index hole is
now on the wrong side of the disk and the index sensor will be unable to
read it so you cannot write to the disk when it's in upside down.
So what? It's a double sided drive, you're already writing to both sides
of the disk so why turn it upside down? Well, what if you've got Print Shop?
Print Shop REQUIRES you to insert the disk upside down so it can read the
back side, but in an XF551 YOU CAN'T!. Plus, Atari 8-bit software is hard
enough to find as it is and when you do it's usually on the BACK side of a
Commodore disk! These disks will not work in an XF551!
Seems that this makes the XF551 a good second drive but not much good if
you've got a lot of 'flippy' software, unless you modify the drive so you can
switch the index sensor on/off manualy. If anyone has an XF551 I would
appreciate it if they could confirm or disprove this.
--
Kevin Thompson {ucbvax,pyramid,nsc}!voder!kevin
"It's a sort of threat, you see. I've never been very good at them
myself but I'm told they can be very effective."