Int 21H, AH=3CH

2 and higher

“CREAT” - CREATE OR TRUNCATE FILE

      AH = 3Ch
      CX = file attributes (see #01401)
      DS:DX -> ASCIZ filename

CF clear if successful

          AX = file handle
      CF set on error
          AX = error code (03h,04h,05h) (see #01680 at AH=59h/BX=0000h)

if a file with the given name exists, it is truncated to zero length
      under the FlashTek X-32 DOS extender, the pointer is in DS:EDX
      DR DOS checks the system password or explicitly supplied password at
        the end of the filename against the reserved field in the directory
        entry before allowing access

Bitfields for file attributes: Bit(s) Description (Table 01401)

0      read-only
1      hidden
2      system
3      volume label (ignored)
4      reserved, must be zero (directory)
5      archive bit
7      if set, file is shareable under Novell NetWare
        

AH=16h,AH=3Dh,AH=5Ah,AH=5Bh,AH=93h,INT 2F/AX=1117h

Text based on Ralf Brown Interrupt List Release 61