>> For now the header/sector-level scanning seems to be about the best >> solution, and will cope with all but one SAM disk I've seen so far :-)
I'm betting that was another Mr Owen creation ;-) Friday, December 10, 2004, 2:41:26 PM, you wrote: Simon> Nev Young wrote: >> why not create an image that is a full track image from index >> hole to index hole including all the inter sector guff. That >> should cover just about everything. Simon> It would indeed, if there was a reliable way to dump them! You'd really Simon> need all the sync marks as well as the raw track data, but even reading the Simon> raw track data is a problem... Simon> Unfortunately, the WD1772-02 controller leaves the address mark detector Simon> enabled during the diagnostic tracks reads, meaning certain patterns in the Simon> data can cause a false sync. If this happens the controller returns MFM Simon> bits instead of data bits from that point on in the track, making what you Simon> read essentially useless. I tried this method when writing the original Simon> MakeSDF scanner, before spotting the problem and working out what the heck Simon> it was doing. Simon> The PC controller allows you to read ID field headers and data, but doesn't Simon> give access to anything in the gap areas. There is a Disk2FDI program that Simon> can do it, but is a commercial program and requires 2 floppy drives. It Simon> spins both drives up and starts the read of a high-density disk in drive 1, Simon> then switches the drive-select to drive 2, with the controller then Simon> returning MFM _and_ data bits for the disk in drive 2. Very clever, but Simon> it's DOS-only and wasn't particularly reliable when I tried it a while ago. Simon> Another option is to use a Catweasel controller card, which can read just Simon> about any disk at very low level. They're not cheap though, and it's not Simon> really something most people will have access to for dumping. Simon> For now the header/sector-level scanning seems to be about the best Simon> solution, and will cope with all but one SAM disk I've seen so far :-) Simon> Si
