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====== Int 21H, AH=0EH ======

===== Version =====

1 and higher

===== Brief =====

SELECT DEFAULT DRIVE

===== Family API =====

[[en:docs:fapi:DosSelectDisk]]

===== 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=[[en:docs:dos:api:int21:29|29H]]) can be used to determine whether a drive letter is valid

===== See also =====

AH=[[en:docs:dos:api:int21:19|19H]],AH=[[en:docs:dos:api:int21:3b|3BH]]

===== Note =====

Text based on [[http://www.cs.cmu.edu/~ralf/files.html|Ralf Brown Interrupt List Release 61]]

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