scc@burl.UUCP (SALLY CATENA) (11/16/83)
I have in the past put a notch on the left side off a SS/DD disk in order to use the other side. Is it possible to do this to a DD/DD disk which only has one notch and flip it to use the other side? Sally Catena burl!scc
notes@pur-ee.UUCP (11/18/83)
#R:burl:-38400:isrnix:8700005:000:1314 isrnix!akp Nov 17 18:37:00 1983 You can't be serious. Double-sided disks are just that -- double-sided. the disk mechanism uses both sides of the disk. If you flip it over, what are you going to use? The OTHER two sides? Also, that technique only works with a subset of computers: it requires that the computer not use the OTHER hole, which is just outside the center hole. That's a timing hole, and the only computer I know of which does NOT use it is the APPLE family, which will write on a waffle and not complain. For other computers, you have to punch ANOTHER hole to match the position of the timing hole when you flip the disk. Lastly, when you flip a disk over, it spins in the OTHER direction, and all the dust which has collected on the jacket comes off onto the disk surface (try brushing a clothes brush the wrong way -- that's the effect inside the disk envelope). This can (obviously) render the disk unusable, but, also, it can damage the heads of the disk DRIVE by passing all this dust under the head. In short, flippy floppies are not all that good an idea. It's probably okay for one-time things like master disks or long-term storage (as opposed to a disk you use daily), and it DOES cut your media cost in half, which is no bad thing. But computer user, beware! -- allan pratt ...decvax!pur-ee!iuvax!isrnix!akp
ABN.ISCAMS%usc-isid@sri-unix.UUCP (11/18/83)
Sally (et al): I suspect not on your notching the DD/DD disk to flip and use the other side. Remember the timing hole at about 1:30 or so just outside the hub of all disks. That kind of has to be at 1:30 or the sensor can't find it. I HAVE cheated with some lousy word processor disks: slit open the disk cover, slid out the floppy itself (horrible, horrible - but I DIDN'T touch the media, honest!), used a one-hold punch to punch a new hole in the cover at 1:30 on the FLIP side, slid back in the media, taped it all together, notched the edge of the cover as you described, and fired it up. Worked just fine, though the disks were NOT rated for double-sided. The key thing was that one-hole punch, though. Regards, David Kirschbaum Toad Hall
burton@fortune.UUCP (11/21/83)
You haven't indicated what system you are running on. I may be wrong, but
most systems also need to see "index," which is a signal generated when the
disk rotates and a small hole appears in the disk in the hole punchout near
the center opening of the disk. Without index, a controller has no way of
knowing where the beginning of the track is on the disk.
I believe that Apple doesn't require index, due to their controller design,
but all other systems do.
There is no reason why you couldn't make a "flippy" from a double-sided disk, but why?
In general, flippy disks are a bad idea, except for archival storage. As a
disk spins, it collects dirt and dust in the lint-free liner, which is the
white material on the inside of the diskette jacket. If you reverse the spin
direction, you can free up some of that dirt, which can and will reach the
drive's read/write head, with unhappy results.
-Phil Burton,
Fortune Systems