On Wed, April 3, 2013 9:08 am, Antitrack@networld.at wrote: > > Zitat von Wolfgang Moser <firstname.lastname@example.org>: > >> Hello Pete, >> >> Pete Rittwage schrieb: >> > Hi guys, >> > >> > With the help of "TeaRex" on my forum, I added a simple way to >> > read/write disk images using the index hole sensor built into the >> 1571. >> > Through this addition, a revelation occurred. >> > >> > We had always assumed (since the 80's) that the Electronic Arts' "fat >> > tracks" protection had 2 tracks (34 and 35) perfectly aligned. I >> added >> > the index hole code and wrote out the disk perfectly aligned to track >> 0 >> > and thought it was beaten. :) >> > >> > Well, it turns out this assumption is *not* true. When reading >> against >> > the index hole, track 35 is actually skewed back 1/4 track or so on >> all >> > the original disks. If I write it back out skewed in this way, it >> > boots. These were never "FAT" tracks at all, just a specific track >> skew >> > between two identical copies of a track. > > That makes perfectly sense, since the time to move the stepper from > Track34 to > Track35 is about the same time as you need to read 1/4 of a track. > I ended up being wrong about this. I had an error with my tools that fooled me. :) - Pete Rittwage Message was sent through the cbm-hackers mailing listReceived on 2013-04-03 19:00:06
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