[net.micro.cpm] Question from a Novice

ABN.ISCAMS@USC-ISID.ARPA (06/22/84)

Jim,

Is your software asking for a single sided double density (SSDD) option
selection?  If not, and it just does DSDD -- a disk rated at SSDD DOES still
have the magnetic media on that "back" side, and it CAN still be formatted
and written to.  (You must have missed the Great Double-Sided Disk Debate
on the net a few months ago!)

It's just that the manufacturer did not certify or warrant or guarantee that
"back" side for double density or something.  Maybe it WILL do just fine,
and maybe it WON'T!  Only your trying will tell!

Lots of people buy El Cheapo (no offense, please - I do it too) single sided
single density disks, punch a couple of holes to tell their disk drive it
IS double sided (it's a physical thing, telling the disk drive), and go right
ahead and format/use DSDD!  Sometimes it works and sometimes...

Now, I do NOT understand why your disk drive isn't picking up the physical
difference (location of timing holes, square write protect notch) between
SSDD and DSDD - maybe one of our Kaypro owners out there can enlighten us?

Regards,
David Kirschbaum
Toad Hall
ABN.ISCAMS@USC-ISID

Chris@USC-ECLB.ARPA (06/22/84)

From:  Christopher Ho <Chris@USC-ECLB.ARPA>

David et al,
	The physical difference between SS and DS diskettes exists only
for 8" diskettes.  5.25" diskettes are basically all identical, and this
is the variety used on all the Kaypros.
						Chris
ps:By identical I do not include soft- vs. hard-sectored, which are
   two different kinds of animal.
-------

bridger@Rand-Unix.ARPA (06/22/84)

From:  Bridger Mitchell <bridger@Rand-Unix.ARPA>

A contributing factor may be the BIOS firmware shipped with
the Kaypro 4's and 10's.  It doesn't correctly support the CPM disk-reset
function call.  A drive, once logged in with a double-sided disk, remains
double-sided until the next warm boot, despite any disk-reset call.
This is a pain in programs that permit disk swapping, if you have
both single and double-sided disks.

One solution is the CP/M upgrade from Plu*Perfect Systems, which does
the disk-resets correctly.

--bridger