Superseded DOS Functions
This index lists DOS version 1.0 services which have been superseded by
services available with DOS 2.0+. The newer services are typically much
easier to use.
Old Function New Function
───────────────────────────── ──────────────────────────────────────
00H Terminate Program 4cH End Program
01H Read Keyboard with Echo 3fH Read File or Device (BX=0)
02H Display Character 40H Write File or Device (BX=1 or 2)
03H Auxiliary Input 3fH Read File or Device (BX=3)
04H Auxiliary Output 40H Write File or Device (BX=3)
05H Print Character 40H Write File or Device (BX=4)
09H Display String 40H Write File or Device (BX=1 or 2)
0aH Buffered Keyboard Input 3fH Read File or Device (BX=0)
0fH Open File with FCB 3dH Open File with Handle
10H Close File with FCB 3eH Close File with Handle
11H Find First File with FCB 4eH Find First File
12H Find Next File with FCB 4fH Find Next File
13H Delete File with FCB 41H Delete File
14H Sequential Read 3fH Read File or Device
15H Sequential Write 40H Write File or Device
16H Create File with FCB 3cH Create File with Handle
17H Rename File with FCB 56H Rename File
1bH Get Default Drive Data 36H Get Disk Free Space
1cH Get Drive Data 36H Get Disk Free Space
21H Random Read 3fH Read File or Device
22H Random Write 40H Write File or Device
23H Get File Size 42H Move File Pointer
24H Set Random Record Number 42H Move File Pointer
26H Create New PSP 4b00H Load and Execute Program
27H Random Block Read 3fH Read File + 42H Move File Pointer
28H Random Block Write 40H Write File + 42H Move File Pointer
INT 20H Terminate Program 4cH End Program
INT 27H Terminate & Stay Res 31H Terminate & Stay Resident
───────────────────────────── ──────────────────────────────────────
Notes: ■ Fns 01H-0cH continue to be needed by TSRs when InDOS is set.
■ Fn 11H is still useful when you need to access a CVF▲ directly
(it returns a starting cluster; see Mapping DOS FAT to MDFAT).
See Also: Obsolete DOS Functions
DOS Function Index - by DOS Version
DOS Versions (summary of differences from version to version)
DOS Functions