DOS Fn 440dH CL=47H: IOCTL Set Access Flag
Compatibility: 4.0 only ◄Undoc►
Expects: AX 440dH
BX drive (0=default, 1=A, 2=B, etc.)
CL 47H
CH 08H (device category: block device)
DS:DX addr of a two-byte structure:
DS:[DX+0] 0
DS:[DX+1] 00H=lock the drive
01H=unlock the drive; deny future access
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Returns: AX error code if CF is set to CY
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Info: Locks or unlocks all read/write access to the specified drive.
The driver may disable all disk access, for instance, when it
detects unformatted media or an invalid boot record.
Note: This function is not documented in official MS-DOS references.
See Also: Fn 44H (IOCTL)
Fn 440dH (generic IOCTL for block devices)
Fn 440dH 67H (query access flag)
DOS Functions
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