DOS Function Index - by Number
This index lists all INT 21H functions, organized by function number,
and identifying the DOS versions under which they are available.
See DOS Function Index - by DOS Version to see functions in the
chronological order in which they were added to DOS.
See DOS Function Index - Quick Reference Subset for a one-screen summary.
Versions DOS Function
ÚÄÄÄÄ¿ ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
³1.0+³ 00H Terminate a Program
³1.0+³ 01H Keyboard Input
³1.0+³ 02H Display Output
³1.0+³ 03H Auxiliary Input
³1.0+³ 04H Auxiliary Output
³1.0+³ 05H Printer Output
³1.0+³ 06H Console I/O
³1.0+³ 07H No Echo Unfiltered Console Input
³1.0+³ 08H No Echo Console Input
³1.0+³ 09H Display String
³1.0+³ 0aH Buffered String Input
³1.0+³ 0bH Check Input Status
³1.0+³ 0cH Clear & Input
³1.0+³ 0dH Reset Disk
³1.0+³ 0eH Select DOS Default Disk
³1.0+³ 0fH Open File via FCB
³1.0+³ 10H Close File via FCB
³1.0+³ 11H Find 1st Matching File via FCB
³1.0+³ 12H Find Next Matching File via FCB
³1.0+³ 13H Delete File via FCB
³1.0+³ 14H Read Sequential File via FCB
³1.0+³ 15H Write Sequential File via FCB
³1.0+³ 16H Create File via FCB
³1.0+³ 17H Rename File via FCB
³?.? ³ 18H (unknown)
³1.0+³ 19H Query DOS Default Disk
³1.0+³ 1aH Set Disk Transfer Address (DTA)
³1.0+³ 1bH Get Drive Info (current disk)
³2.0+³ 1cH Get Drive Info (any disk)
³?.? ³ 1dH (unknown)
³?.? ³ 1eH (unknown)
³2.0+³ 1fH Get Drive Parameter Block (current disk)
³?.? ³ 20H (unknown)
³1.0+³ 21H Read Random File Record
³1.0+³ 22H Write Random File Record
³1.0+³ 23H Query File Size via FCB
³1.0+³ 24H Set Random File Block Address
³1.0+³ 25H Set Interrupt Vector
³1.0+³ 26H Create Program Segment Prefix
³1.0+³ 27H Read Random File Block
³1.0+³ 28H Write Random File Block
³1.0+³ 29H Parse Filename
³1.0+³ 2aH Query DOS Date
³1.0+³ 2bH Set DOS Date
³1.0+³ 2cH Query DOS Time
³1.0+³ 2dH Set DOS Time
³1.0+³ 2eH Set/Reset Verify Switch
³2.0+³ 2fH Query Disk Transfer Address (DTA)
³2.0+³ 30H Get DOS Version Number
³2.0+³ 31H Terminate & Stay Resident
³2.0+³ 32H Get DPB (Drive Parameter Block)
³2.0+³ 3300H Query Break-Check Flag
³2.0+³ 3301H Set Break-check level
³2.0+³ 3305H Get Boot Drive
³5.0+³ 3306H Get DOS Version Info (and HMA use)
³2.0+³ 34H Get InDOS Address (DOS Reentrancy Status)
³2.0+³ 35H Get Interrupt Vector
³2.0+³ 36H Get Disk Free Space
³?.? ³ 3700H Query Switchar
³?.? ³ 3701H Set Switchar
³2.0+³ 38H Get/Set Country-dependent Info
³2.0+³ 39H Create a New Directory -- MKDIR
³2.0+³ 3aH Delete a Directory -- RMDIR
³2.0+³ 3bH Set DOS Default Directory -- CHDIR
³2.0+³ 3cH Create a File via Handle
³2.0+³ 3dH Open a File via Handle
³2.0+³ 3eH Close a File Handle
³2.0+³ 3fH Read from File via Handle
³2.0+³ 40H Write to File via Handle
³2.0+³ 41H Delete File
³2.0+³ 42H Set File Pointer
³2.0+³ 4300H Query File Attribute
³2.0+³ 4301H Set File Attribute
³2.0+³ 4400H IOCTL Query Device/File Flags
³2.0+³ 4401H IOCTL Set Device/File Flags
³2.0+³ 4402H IOCTL Receive Control Data from Char Device
³2.0+³ 4403H IOCTL Send Control Data to Character Device
³2.0+³ 4404H IOCTL Receive Control Data from Block Device
³2.0+³ 4405H IOCTL Send Control Data to Block Device
³2.0+³ 4406H IOCTL Query Handle Input Status
³2.0+³ 4407H IOCTL Query Handle Output Status
³3.0+³ 4408H IOCTL Does Drive Use Removable Media
³3.1+³ 4409H IOCTL Is Drive Remote
³3.1+³ 440aH IOCTL Is File/Device Remote
³3.1+³ 440bH IOCTL Set Sharing Retry Count
³3.3+³ 440cH 45H IOCTL Set Retry Iteration Count
³3.3+³ 440cH 4AH IOCTL Select Code Page
³3.3+³ 440cH 4CH IOCTL Start Code Page Prepare
³3.3+³ 440cH 4DH IOCTL End Code Page Prepare
³4.0+³ 440cH 5Fh IOCTL Set Display Mode
³3.3+³ 440cH 65H IOCTL Query Retry Iteration Count
³3.3+³ 440cH 6AH IOCTL Query Current Code Page
³3.3+³ 440cH 6BH IOCTL Query Code Page List
³4.0+³ 440cH 7Fh IOCTL Query Display Mode
³3.2+³ 440dH 40H IOCTL Set Device Parameters
³3.2+³ 440dH 41H IOCTL Write Track on Logical Drive
³3.2+³ 440dH 42H IOCTL Format Track on Logical Drive
³4.0+³ 440dH 46H IOCTL Set Media ID
³3.2+³ 440dH 47H IOCTL Set Access Flag
³3.2+³ 440dH 60H IOCTL Query Device Parameters
³3.2+³ 440dH 61H IOCTL Read Track on Logical Drive
³3.2+³ 440dH 62H IOCTL Verify Track on Logical Drive
³5.0+³ 440dH 66H IOCTL Query Media ID
³4.0 ³ 440dH 67H IOCTL Query Access Flag
³3.2+³ 440dH 68H IOCTL Sense Media Type
³3.2+³ 440eH IOCTL Query Logical Drive Map
³3.2+³ 440fH IOCTL Set Logical Drive Map
³5.0+³ 4410H IOCTL Query IOCTL Support for Handle
³5.0+³ 4411H IOCTL Query IOCTL Support for Device
³2.0+³ 45H Duplicate a File Handle
³2.0+³ 46H Redirect a Handle
³2.0+³ 47H Query Default Directory
³2.0+³ 48H Allocate Memory / Query Free Memory
³2.0+³ 49H Free Allocated Memory Block
³2.0+³ 4aH Shrink or Expand a Memory Block
³2.0+³ 4b00H Execute a Program -- EXEC
³2.0+³ 4b01H Load Program
³2.0+³ 4b03H Load Overlay
³5.0+³ 4b05H Set Execution State
³2.0+³ 4cH Terminate Program
³2.0+³ 4dH Get Program Exit Code
³2.0+³ 4eH Find 1st Matching File
³2.0+³ 4fH Find Next Matching File
³2.0+³ 50H Set PSP
³2.0+³ 51H Query Current PSP
³????³ 52H Get DOS Variables
³????³ 53H Convert BPB to DPB
³2.0+³ 54H Get DOS Verify State
³2.0+³ 56H Rename/Move a File
³2.0+³ 5700H Query File Time/Date
³2.0+³ 5701H Set File Time/Date
³3.0+³ 5800H Query Memory Allocation Strategy
³3.0+³ 5801H Set Memory Allocation Strategy
³5.0+³ 5802H Query Upper-Memory Link State
³5.0+³ 5803H Set Upper-Memory Link State
³3.0+³ 59H Get Extended Error Info
³3.0+³ 5aH Create Unique Temporary File
³3.0+³ 5bH Create New File
³3.1+³ 5c00H Lock File Access
³3.1+³ 5c01H Unlock File Access
³4.0+³ 5d0aH Set Extended Error
³3.1+³ 5e00H Query Network Node Name
³3.1+³ 5e02H Set Network Printer Setup
³3.1+³ 5e03H Query Network Printer Setup
³3.1+³ 5f02H Network Query Assign-List Entry
³3.1+³ 5f03H Make Network Connection
³3.1+³ 5f04H Delete Network Connection
³????³ 60H Query TrueName
³2.0+³ 62H Query Current PSP
³3.3+³ 6501H Get Extended Country Information
³3.3+³ 6504H Get Uppercase Table
³3.3+³ 6505H Get Filename Character Table
³3.3+³ 6506H Get Collating Sequence Table
³3.3+³ 6507H Get Double-Byte Character Set
³3.3+³ 6520H Upshift Character
³3.3+³ 6521H Upshift String
³3.3+³ 6522H Upshift ASCIIZ String
³3.3+³ 6601H Query Active Code Page
³3.3+³ 6602H Activate Code Page
³3.3+³ 67H Set File Handle Count
³3.3+³ 68H Commit File
³4.0+³ 6cH Extended Open/Create
ÀÄÄÄÄÙ
See Also: Superseded DOS Functions
Obsolete DOS Functions
DOS Versions (summary of differences from version to version)
-*-