Function 440Dh Minor Code 66h Get Media ID

mov bx, Drive ;0 = default, 1 = A, 2 = B, etc.

mov ch, 08h ;device category (must be 08h)

mov cl, 66h ;Get Media ID

mov dx, seg MediaID

mov ds, dx

mov dx, offset MediaID ;ds:dx points to MID structure

mov ax, 440Dh ;IOCTL for Block Device

int 21h

jc error_handler ;carry set means error

Get Media ID (Function 440Dh Minor Code 66h) returns the volume label, serial number and file system for the specified drive.

Parameters

Drive

Specifies the drive for which information is to be returned (0 = default drive, 1 = A, 2 = B, etc.).

MediaID

Points to a MID structure that receives information that uniquely identifies a disk or other storage medium. The MID structure has the following form:

MID STRUC

midInfoLevel dw 0 ;information level

midSerialNum dd ? ;serial number

midVolLabel db 11 dup (?) ;ASCII volume label

midFileSysType db 8 dup (?) ;file system type

MID ENDS

For a full description of the MID structure, see Chapter 3, “File System.”

Return Value

If the function is successful, the carry flag is clear, and the parameter block is filled in with information about the disk. Otherwise, the carry flag is set and the AX register contains an error value, which may be one of the following:

Value

Name

0001h	ERROR_INVALID_FUNCTION
0002h	ERROR_FILE_NOT_FOUND
0005h	ERROR_ACCESS_DENIED

Comments

Get Media ID returns 0002h (ERROR_FILE_NOT_FOUND) if the specified drive number is invalid.