INT 13H (0x13) Function 43H (0x43 or 67) Extended Write 44H (0x44 or 68) Verify Sectors 45H (0x45 or 69) Lock/Unlock Drive (IBM/MS INT 13H Extensions)

INT 13H (0x13)

Function 43H (0x43 or 67) --> Extended Write (IBM/MS INT 13H Extensions)

Call with: AH = 43H
AL = write flags (See the table in
comments)
DL = drive number.
DS:SI = disk address packet

Return: If Function Successful,
Carry Flag = clear
AH = 00H

If Function Unsuccessful,
Carry Flag = set
AH = error code

Comments:

This function is the extension for disk write function. If the function is successful carry flag is clear and AH register is 00H, else Carry flag is set and AH returns the error code. The block count field of disk address packet is set to number of blocks successfully. The information of write flags for different versions has been given in the following table:

INT 13H (0x13)

Function 44H (0x44 or 68) --> Verify Sectors (IBM/MS INT 13H Extensions)

Call with: AH = 44H
DL = drive number
DS:SI = disk address packet

Return: If Function Successful,
Carry Flag = Clear
AH = 00H

If Function Unsuccessful,
Carry Flag = Set
AH = error code

Comments:

This function is the extension for Verify Sectors function. If the function is successful carry flag is clear and AH register is 00H, else Carry flag is set and AH returns the error code. The block count field of disk address packet is set to number of blocks successfully

INT 13H (0x13)

Function 45H (0x45 or 69) --> Lock/Unlock Drive (IBM/MS INT 13H Extensions)

Call with: AH = 45H
AL = Operation Number (See the Table in
comments)
DL = Drive number

Return: If Function Successful,
Carry Flag = Clear
AH = 00H
AL = Lock State (00H = Unlocked)

If Function Unsuccessful,
Carry Flag = Set
AH = Error code

Comments:

This function is used to Lock/Unlock the drive. This function is required to be supported for any removable drives numbered 80H or higher. Up to 255 locks may be placed on a drive, and the media will not be physically unlocked until all locks have been removed.

If the function is successful carry flag is clear and AH register is 00H, else Carry flag is set and AH returns the error code.

Operation numbers for different Lock/Unlock operation of the drive have been given in the following table:

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