01-04-2014, 03:03 PM
You will start reading at a random position when there is no index pulse available - like when reading a disk that has been flipped over. Unless it has a second index hole you can't use the index pulse to start the read, so it has to be "ignored". When this occurs, the track is read using a virtual index pulse so that exactly one revolution is read. You would NEVER use this option for 3.5" disks.
The FIND INVALID will locate a write splice if one exists. There is preliminary code for the Amiga/ST, but complete code for the C64 GCR stuff.
Apparently I can not ADD!! I just discovered why DrCoolZic was confused over the number of tracks. 0x10->0x2A4 is 165 entries, which is not an even multiple of 2. So, I got rid of the reserved long word at 0x2A4 (glad that was there!) and now there are 166 entries. So, for Amiga/ST disks that is tracks 0-82 (83 tracks), bottom and top heads. I changed the info in the specs file to reflect this change and I am changing the software as well.
The FIND INVALID will locate a write splice if one exists. There is preliminary code for the Amiga/ST, but complete code for the C64 GCR stuff.
Apparently I can not ADD!! I just discovered why DrCoolZic was confused over the number of tracks. 0x10->0x2A4 is 165 entries, which is not an even multiple of 2. So, I got rid of the reserved long word at 0x2A4 (glad that was there!) and now there are 166 entries. So, for Amiga/ST disks that is tracks 0-82 (83 tracks), bottom and top heads. I changed the info in the specs file to reflect this change and I am changing the software as well.