Some questions regarding Apple II flippy disk

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martysmarty
Posts: 5
Joined: Thu Feb 15, 2018 6:21 pm

Some questions regarding Apple II flippy disk

Post by martysmarty » Fri Feb 16, 2018 9:42 am

Hi guys,

I've been using my Kryoflux for a while, although mainly with Amiga and PC disks. Now however, I received a, by the looks of it, Apple II DOS 3.3 disk. The label gives a description of what's on the front side, and what's on the back side.

Now I have been reading a lot about these flippy disks, drive modifications, and so on. I am puzzled about some things though, so I'm hoping someone can help me answer these questions. FYI, my drive has not been modified yet. It is a 1.2 MB drive

- I usually only make STREAM dumps of my disks, so I can later on convert them. When I make a dump of this disk, I see that it actually is reading track 00.0, then 00.1, 01.0, 01.1 etc etc. From what I understand, this means it's actually already readying both sides of the disk?

- When I analyze the stream files, I can actually see that side 0 has several tracks with data, and side 1 as well. They are however not identical. Shouldn't this mean that the flippy side actually got read correctly?

- And now to the part that puzzles me. At this point I'm like, okaaaaay, so does my drive already read both sides? Analyzer seems to show this. Well than let me make a .dsk file (tried both image type 8 and 8a). I first make 1 for side 0, and look, Ciderpress and some other applications actually see some files. However, when I make one for side 1, I'm getting the identical file as from side 0. What's going on here? Is DTC just refusing to use side 1, and making another one of side 0?

I also tried making 1 dsk file from both sides, but that didn't give me anything more either.

Anyone? :)

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IFW
Posts: 3079
Joined: Mon Nov 08, 2010 2:42 pm

Re: Some questions regarding Apple II flippy disk

Post by IFW » Wed Mar 07, 2018 12:50 pm

1, Yes, that means both sides are read.
2, no, because the first 8 tracks (in 96 TPI) or 4 tracks (in 48 TPI) are missing from side 1. They are the data tracks at track -8, -6, -4, -2... that's why a modified drive is required for flippy disks - you should read tracks before track 0, which is simply impossible ;)
So yes, you are reading side 1, but the data (in the case of A2 or C64) from the first 4 tracks on side 1 will not be present; you first track dumped on track 0 side 1 is actually the 5th track...
3, That sounds like a parameter error; please post your command for conversion. Also note, that the image will not be correct anyway for side 1 unless you use a flippy modded drive, since the first 4 tracks will be missing.

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