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Can you *write* side 1 of a flippy disk?

Posted: Fri Apr 06, 2018 9:15 am
by Modeler
Quick question, is it possible to write both sides (or just side 1) of a disk in flippy mode? I can read either or both sides in flippy mode no problem, but I can't seem to get DTC to attempt to write side 1.

Clearly this poses a challenge, since the head would need to be stepped to track -8 and the data written backwards, but I had hoped something like this would work:

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dtc -f<filename>.g64 -dd1 -g1 -y -b-8 -w
Is this in any way supported and if not, is it possible to write a dump of a flippy disk back to a real floppy using stream files?

Thanks!

EDIT: This is the error I get when I run the above command:

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$ ./dtc -frr_disk2_s0.g64 -dd1 -g1 -y -b-8 -w
Image name: rr_disk2_s0.g64
Image type: G64
Image sides: 1
Image tracks: 84
Side 0: td: 2, cf: off, data: 40, unformatted: 44, nfr: 0
Filter mode: side -wg: 3, crosstalk -wk: 3
Side mode: side -g: 1, td -k: 2, flip -wy: 0[1], flippy -y: 0[1]
Write mode: bias -wb: 1, erase -we: 2
The image to be written would be unformatted; change settings
If what I'm trying to do is not possible, fair enough. Just hoping someone can confirm as I've done a fair few searches and couldn't find anything.

Re: Can you *write* side 1 of a flippy disk?

Posted: Sat Apr 07, 2018 3:39 pm
by mr.vince
Not implemented yet, you'll need a disk with two index holes and flip it over...

Re: Can you *write* side 1 of a flippy disk?

Posted: Sun Apr 08, 2018 4:09 pm
by Modeler
Thought so, ah well. Thanks for confirming.

Re: Can you *write* side 1 of a flippy disk?

Posted: Fri Apr 05, 2019 11:27 am
by dandee
Hey.

Quite stranded here as well. Any news of implementing write support for both sides? I know, kryoflux is for preservation, but writing back the second side would be really a useful feature.

cheers.

Re: Can you *write* side 1 of a flippy disk?

Posted: Sun Apr 14, 2019 10:48 am
by Modeler
dandee wrote:
Fri Apr 05, 2019 11:27 am
Quite stranded here as well. Any news of implementing write support for both sides? I know, kryoflux is for preservation, but writing back the second side would be really a useful feature.
I got around this by making a second index hole in the blank floppy with a ticket punch:

Image

It's not an ideal solution but it's effective. Some original 5.25" floppies had two index holes and two notches, assuming the original mastering process would sometimes hit a similar issue back in the day. One advantage is that I can write both sides of an imaged disk using an unmodified / non-flippy drive.

I don't want to insult anyone's intelligence, but I ought to point out that if you want to do this you need to punch through both sides of the jacket individually, in the same place (not just straight through as that would put a hole through the disk cookie as well). I dissected a dead disk and used its jacket to create a template for this.

Re: Can you *write* side 1 of a flippy disk?

Posted: Sun Apr 14, 2019 5:09 pm
by brightcaster
I think that it isn't that easy to implement writing to the second side of a flippy disk!

You have to keep in mind, that the index signal is alway at the wrong position on the second side. So if you want to start writing at the correct position you have to start in blind flight about three quarters of a revolution after the index pulse. And you have to start writing backwards (with the end of the track) hoping that the last bits (start of the track) will fall just into the right position.

I guess that this will need much more precision than 20 to 30 years old drives can deliver...

David