In article Pine.LNX.4.64.1101131227510.29295@dholavira.tuxers.net, David C Niemi wrote:
Back in the day 5.25" disks were sometimes (or usually) laid out with sectors out of order, because CPUs were really slow and couldn't read the sectors as they came by and fdcs did not have a buffer to hold the sectors until the host requested them.
Yes, I remember the days of interleaving and slewing.
So they would take 2 or 3 revolutions to read each side of the disk. Could it be you just start at 2 but there is a 1 later on?
No, sector 1 is deffo toast. A card called a "Catweasel" arrived at my house this AM and I can see the damage up close. Sector 1 is wreckage early on, and the IDAM headers suffer heavy damage, and even when they are there, the header CRC is often bad. Fortunately, the DAMs are mostly good, and I'm hoping the data CRCs are also good, so I should be able to pull the data from the raw track dump.
Ian