Function 440Dh Minor Code 46h Set Media ID

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

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

mov cl, 46h ;Set 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

Set Media ID (Function 440Dh Minor Code 46h) sets the volume label, serial number, and file system for the specified drive.

Parameters

Drive

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

MediaID

Points to a MID structure that contains 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. 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

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