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I thought MS-DOS had special handling for A: and B: since it allowed you to copy from A: to B: even with just one floppy drive.
by brewmarche 20d ago
I thought MS-DOS had special handling for A: and B: since it allowed you to copy from A: to B: even with just one floppy drive.
- dspillett 20d agoYes, it did, or something did (maybe the individual commands rather than it being through the OS). I'd completely forgotten about that…
- jasomill 20d agoBoth of these things are true: commands like diskcopy have special handling to allow the same drive to be used as both source and destination, and the DOS I/O has special handling to request disk changes from A: to B: on single-drive systems for programs that lack specific support.
- jasomill 20d agoIt does. https://github.com/microsoft/MS-DOS/blob/2d04cacc5322951f187bb17e017c12920ac8ebe2/v4.0-ozzie/bin/DISK2/BIOS/IBMBIO.ASM#L1428 https://github.com/microsoft/MS-DOS/blob/2d04cacc5322951f187...