On Wed, 9 Aug 2017, Mike Stein via cctalk wrote:
Interesting reading here under disk formats:
Sounds like there were two Tarbell controllers, single and double
density but both single-sided ?
Also sounds like the FAT12 disk formats were not quite MS-DOS compatible...
There are also, of course MANY MS-DOS formats that are not PC-DOS
compatible, nor compatible with "modern" MS-DOS.
Some are hardware incompatible, such as Sirius/Victor 9000.
Some are not recognized by "modern" MS-DOS, but nevertheless are
straight-forward to read/write with IMD, XenoCopy, 22Disk, etc.
Those range from ones with different sector sizes, to ones that are ALMOST
PC-DOS, but with different number of DIRectory sectors, etc.