Int 21H Function 44H
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The IOCTL subfunctions and the MS-DOS versions in which they first be-
came available are:
MS-DOS
Subfunction Name version
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00H Get Device Information 2.0
01H Set Device Information 2.0
02H Receive Control Data from 2.0
Character Device Driver
03H Send Control Data to Character 2.0
Device Driver
04H Receive Control Data from Block 2.0
Device Driver
05H Send Control Data to Block 2.0
Device Driver
06H Check Input Status 2.0
07H Check Output Status 2.0
08H Check If Block Device Is 3.0
Removable
09H Check If Block Device Is Remote 3.1
0AH Check If Handle Is Remote 3.1
0BH Change Sharing Retry Count 3.1
0CH Generic I/O Control for Character
Devices
CL = 45H: Set Iteration Count 3.2
CL = 4AH: Select Code Page 3.3
CL = 4CH: Start Code Page 3.3
Preparation
CL = 4DH: End Code Page 3.3
Preparation
CL = 5FH: Set Display Information 4.0
CL = 65H: Get Iteration Count 3.2
CL = 6AH: Query Selected Code Page 3.3
CL = 6BH: Query Prepare List 3.3
CL = 7FH: Get Display Information 4.0
0DH Generic I/O Control for Block
Devices
CL = 40H: Set Device Parameters 3.2
CL = 41H: Write Track 3.2
CL = 42H: Format and Verify Track 3.2
CL = 47H: Set Access Flag 4.0
CL = 60H: Get Device Parameters 3.2
CL = 61H: Read Track 3.2
CL = 62H: Verify Track 3.2
CL = 67H: Get Access Flag 4.0
0EH Get Logical Drive Map 3.2
0FH Set Logical Drive Map 3.2
Only IOCTL Subfunctions 00H, 06H, and 07H may be used for handles asso-
ciated with files. Subfunctions 00H-08H are not supported on network
devices.
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