This index lists DOS version 1.0 services which have been superseded by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).

DOS Versions (summary of differences from version to version)

Superseded DOS Functions