en:docs:dos:api:int21:0e

Note: This API call is for DOS personality only. Use Family API for portability.

2018/09/07 07:04 · prokushev

Int 21H, AH=0EH

Version

1 and higher

Brief

SELECT DEFAULT DRIVE

Family API

Input

      AH = 0Eh
      DL = new default drive (00h = A:, 01h = B:, etc)

Return

AL = number of potentially valid drive letters

Notes

under Novell NetWare, the return value is always 32, the number of drives that NetWare supports

under DOS 3.0+, the return value is the greatest of 5, the value of LASTDRIVE= in CONFIG.SYS, and the number of drives actually present on a DOS 1.x/2.x single-floppy system, AL returns 2 since the floppy may be accessed as either A: or B: otherwise, the return value is the highest drive actually present

DOS 1.x supports a maximum of 16 drives, 2.x a maximum of 63 drives, and 3+ a maximum of 26 drives

under Novell DOS 7, this function returns the correct LASTDRIVE value even when the undocumented LASTDRIVE=27..32 directive was used in CONFIG.SYS

“parse FCB” (see AH=29h) can be used to determine whether a drive letter is valid

See also

AH=19h,AH=3Bh,AH=DBh

Note


en/docs/dos/api/int21/0e.txt · Last modified: 2020/12/07 09:56 by prokushev