[net.micro] Checking a floppy disk for blank

bill@hp-pcd.UUCP (bill) (09/30/86)

Your test only reveals whether or not a boot sector exists (which
effectively tells you if the disk has been formatted or not).  It
does not tell you if a FORMATTED DOS disk is "blank" (i.e., contains
no files).  Once you've determined that the boot sector exists,
you can find out more about the disk by:

	* Examining the boot sector to see if it is a DOS disk.
	  (DOS boot sectors begin with a jump instruction, followed
	  by a DOS revision string.)

	* On a DOS disk, the BPB (also found in the boot sector)
	  will tell you where the root directory is located.
	  You can scan the root directory to see if the disk contains
	  a volume label and/or any files or subdirectories.

	* Note that if the first two files on the disk are named something
	  like IBMBIO.COM and IBMDOS.COM, the disk has an operating
	  system on it.  Also note that just because you typed "dir"
	  and saw no files doesn't necessarily mean there's nothing
	  on the disk -- there may be hidden files.)

Of course, if all you want to know is whether or not the disk has been
formatted, the Int 13h "Verify Sectors" function is the easiest way to
go.

bill frolik
hp-pcd!bill