When a disk drive looks at a diskette to determine whether it is formatted, what does it look at? Does it look at the information on the disk (e.g., from the boot sector) or the physical properties of the disk (e.g., magnetic properties)? Or both? Also, I am confused if MFM and GCR are different physical standards or different in terms of the information placed onto the floppy diskette. Thanks.

MS DOS and compatible only use FAT
12/16/32, therefore discussing any other
File Allocation Indexing is outside the
scope of this FORUM which after all is
called DOS Standalone.

Try the BeOS Forum ?

You can compare an unformatted disk with a blank piece of paper. Formatting is like lining up the paper with the type of line spacing (ie. sectors) the OS can read.
If the OS cannot recognize the line spacing, it conciders the disk unformatted.

So regaring you question; it is information on the disk that differs.

Nigel