This index lists all INT 21H functions, organized by function number,
and identifying the DOS versions under which they are available.
chronological order in which they were added to DOS.
1.0+ 00H Terminate a Program
1.0+ 04H Auxiliary Output
1.0+ 07H No Echo Unfiltered Console Input
1.0+ 08H No Echo Console Input
1.0+ 0aH Buffered String Input
1.0+ 0bH Check Input Status
1.0+ 0eH Select DOS Default Disk
1.0+ 0fH Open File via FCB
1.0+ 10H Close File via FCB
1.0+ 11H Find 1st Matching File via FCB
1.0+ 12H Find Next Matching File via FCB
1.0+ 13H Delete File via FCB
1.0+ 14H Read Sequential File via FCB
1.0+ 15H Write Sequential File via FCB
1.0+ 16H Create File via FCB
1.0+ 17H Rename File via FCB
1.0+ 19H Query DOS Default Disk
1.0+ 1aH Set Disk Transfer Address (DTA)
1.0+ 1bH Get Drive Info (current disk)
2.0+ 1cH Get Drive Info (any disk)
2.0+ 1fH Get Drive Parameter Block (current disk) wasUndoc
1.0+ 21H Read Random File Record
1.0+ 22H Write Random File Record
1.0+ 23H Query File Size via FCB
1.0+ 24H Set Random File Block Address
1.0+ 25H Set Interrupt Vector
1.0+ 26H Create Program Segment Prefix
1.0+ 27H Read Random File Block
1.0+ 28H Write Random File Block
1.0+ 2eH Set/Reset Verify Switch
2.0+ 2fH Query Disk Transfer Address (DTA)
2.0+ 30H Get DOS Version Number
2.0+ 31H Terminate & Stay Resident
2.0+ 3300H Query Break-Check Flag
2.0+ 3301H Set Break-check level
5.0+ 3306H Get DOS Version Info (and HMA use)
2.0+ 34H Get InDOS Address (DOS Reentrancy Status) wasUndoc
2.0+ 35H Get Interrupt Vector
2.0+ 36H Get Disk Free Space
2.0+ 38H Get/Set Country-dependent Info
2.0+ 39H Create a New Directory -- MKDIR
2.0+ 3aH Delete a Directory -- RMDIR
2.0+ 3bH Set DOS Default Directory -- CHDIR
2.0+ 3cH Create a File via Handle
2.0+ 3dH Open a File via Handle
2.0+ 3eH Close a File Handle
2.0+ 3fH Read from File via Handle
2.0+ 40H Write to File via Handle
2.0+ 42H Set File Pointer
2.0+ 4300H Query File Attribute
2.0+ 4301H Set File Attribute
2.0+ 4400H IOCTL Query Device/File Flags
2.0+ 4401H IOCTL Set Device/File Flags
2.0+ 4402H IOCTL Receive Control Data from Char Device
2.0+ 4403H IOCTL Send Control Data to Character Device
2.0+ 4404H IOCTL Receive Control Data from Block Device
2.0+ 4405H IOCTL Send Control Data to Block Device
2.0+ 4406H IOCTL Query Handle Input Status
2.0+ 4407H IOCTL Query Handle Output Status
3.0+ 4408H IOCTL Does Drive Use Removable Media
3.1+ 4409H IOCTL Is Drive Remote
3.1+ 440aH IOCTL Is File/Device Remote
3.1+ 440bH IOCTL Set Sharing Retry Count
3.3+ 440cH 45H IOCTL Set Retry Iteration Count
3.3+ 440cH 65H IOCTL Query Retry Iteration Count
3.2+ 440dH 41H IOCTL Write Track on Logical Drive
3.2+ 440dH 42H IOCTL Format Track on Logical Drive
3.2+ 440dH 61H IOCTL Read Track on Logical Drive
3.2+ 440dH 62H IOCTL Verify Track on Logical Drive
3.2+ 440eH IOCTL Query Logical Drive Map
3.2+ 440fH IOCTL Set Logical Drive Map
5.0+ 4410H IOCTL Query IOCTL Support for Handle
5.0+ 4411H IOCTL Query IOCTL Support for Device
2.0+ 45H Duplicate a File Handle
2.0+ 46H Redirect a Handle
2.0+ 47H Query Default Directory
2.0+ 48H Allocate Memory / Query Free Memory
2.0+ 49H Free Allocated Memory Block
2.0+ 4aH Shrink or Expand a Memory Block
2.0+ 4b00H Execute a Program -- EXEC
5.0+ 4b05H Set Execution State
2.0+ 4cH Terminate Program
2.0+ 4dH Get Program Exit Code
2.0+ 4eH Find 1st Matching File
2.0+ 4fH Find Next Matching File
2.0+ 54H Get DOS Verify State
2.0+ 56H Rename/Move a File
2.0+ 5700H Query File Time/Date
2.0+ 5701H Set File Time/Date
3.0+ 5800H Query Memory Allocation Strategy
3.0+ 5801H Set Memory Allocation Strategy
5.0+ 5802H Query Upper-Memory Link State
5.0+ 5803H Set Upper-Memory Link State
3.0+ 59H Get Extended Error Info
3.0+ 5aH Create Unique Temporary File
3.1+ 5c00H Lock File Access
3.1+ 5c01H Unlock File Access
4.0+ 5d0aH Set Extended Error
3.1+ 5e00H Query Network Node Name
3.1+ 5e02H Set Network Printer Setup
3.1+ 5e03H Query Network Printer Setup
3.1+ 5f02H Network Query Assign-List Entry
3.1+ 5f03H Make Network Connection
3.1+ 5f04H Delete Network Connection
3.3+ 6501H Get Extended Country Information
3.3+ 6504H Get Uppercase Table
3.3+ 6505H Get Filename Character Table
3.3+ 6506H Get Collating Sequence Table
3.3+ 6507H Get Double-Byte Character Set
3.3+ 6520H Upshift Character
3.3+ 6521H Upshift String
3.3+ 6522H Upshift ASCIIZ String
3.3+ 6601H Query Active Code Page
3.3+ 6602H Activate Code Page
3.3+ 67H Set File Handle Count
4.0+ 6cH Extended Open/Create
DOS Versions (summary of differences from version to version)