DIVerify
DIVerify Verify readability of a disk
#include <DiskInit.h> Disk Initialization Package
OSErr DIVerify(drvNum );
short drvNum ; drive to verify (1=internal floppy)
returns Error Code; 0=no error
DIVerify attempts to read all of a diskette and returns an Error Code if any
problems are found. This low-level read does not verify the integrity of the
file information on the disk. It is meant to be used directly after a low-level
format (see DIFormat).
drvNum identifies which drive contains the disk to verify. Historically,
1=internal, 2=external, and number higher than 3 are hard disks.
See GetDrvQHdr for a way to get a list of "hard" drive numbers.
Returns: an operating system Error Code. It will be one of:
noErr (0) No error
firstDskErr (-84) ... through ...
lastDskErr (-64) (low-level disk errors)

Notes: This function is performed automatically by DIBadMount (which itself is
performed automatically most of the time).
DIVerify does not affect the contents of the disk.