rb1773: Make 48 TPI floppy disks readonly in 96 TPI drives Deny the disk destroying write with the narrower heads of the 96 tpi drive when the user has placed a 48 tpi disk in the 96 tpi drive so he can read it. Double stepping the drive is then done automatically so as to stay in mechanical synch with the tracks on a 48 tpi disk. But that, until now, did not make the disk read-only, this patch does that. Patch by Gene Heskett and Robert Gault.