PEPRBV%CFAAMP.BITNET@IBM1.CC.Lehigh.Edu (Bob Babcock) (07/19/89)
MIROWSKI@FRECP12.BITNET writes: >It's rarely necessary to care about the distinction between 360 Ko and >1.2 Mo disks, because the information about the format is in the second >sector of the disk (the first FAT sector) and DOS will take this second >information in consideration. The information is also in the Bios Parameter Block (BPB) in the boot sector, and you're asking for trouble if the FAT and BPB disagree. A while back there was a claim in PC Magazine that PC-DOS 3.3 required that the OEM id field in the boot sector contain the characters "IBM". The evidence offered for this was that if the boot sector on a disk which PC-DOS 3.3 rejected was replaced by a boot sector from an acceptable disk, the disk became acceptable. In fact, what was really happening was that there was bad information in the BPB, and PC-DOS was complaining about this. I have a program called SCAT, which I got off of BIX, which writes a valid boot sector on a floppy. The original purpose was to replace a non-standard boot sector which FastBack writes, but perhaps it would also be useful for removing a boot sector virus. If there's any interest, I could send a copy to the moderator for posting.