GCR is Group Code Recording, used on the Apple II, Commodore 1541 drive
and Amiga (and others) use a different encoding scheme than the normal
FM (Frequency Modulation) or MFM (Modified Frequency Modulation)
encoding formats used by a majority of floppy disk controllers.
There is a very good description of floppy encoding formats here:
https://extrapages.de/archives/20190102-Floppy-notes.html
On 11/3/2022 5:46 PM, Grant Taylor via cctalk wrote:
On 11/3/22 4:35 PM, Fred Cisin via cctalk wrote:
Also GCR, not MFM. NOT readable with a PC FDC.
Please expand "GCR".