13 Sep
2013
13 Sep
'13
2:08 p.m.
Tony Duell wrote:
This may be a
silly question, but I'm looking for confirmation that dssd (d=
ouble sided single density) 8" floppies are usable in a sssd (single sided =
single density) drive such as the Shugart SA800.
Not directly.
The single-sided and double-sided disks have the index hole (in the
jacket) in a different place. The single-sideed (single head) drive had
one indexc sensor, to line up with the hole in the single-sided disk. The
double-head drive (SA850, etc) has 2 index sensors, one to line up with
each hole. Of course when a particualr disk is inserted in a double-head
drive, only one index sensor will be active (the other will be blocked by
the opaque disk jacket), and by detecting which sensor is active, the
drive can signal to the conttoller whether it's a single or double sided
disk.
If you want to use some blank double-sided disks in a signle-sided drive
you need to punch and extra hole in the jacket (and really, block up the
exisitng hole in case they are aver put in a double-head drive).
If so, can the
floppy be manually flipped over and the other side also be r=
ead and written to, therefore having both side containing data?
Yes, but in that case you need to punch another index hole so that the
index sensor can work when the disk is flipped over. 8" disks have the
write-protect notch covered to enable writing (the oposite of the 5.25"
convention, and IMHO a lot more sensible) so you don't need to cut
another write-protect notch unless you want to be able to inhibit writing
to the other side of the disk).
Of course this will not allow you to read or write a disk that is to be
used ina double-head drive. The second side will be recorded backwards