en:docs:dos:api:int21:1b

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en:docs:dos:api:int21:1b [2020/12/08 08:44] – prokusheven:docs:dos:api:int21:1b [2024/05/02 02:39] (current) – prokushev
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  AL = sectors per cluster (allocation unit)  AL = sectors per cluster (allocation unit)
-        CX = bytes per sector + CX = bytes per sector 
-        DX = total number of clusters + DX = total number of clusters 
-        DS:BX -> media ID byte (see #01356)+ DS:BX -> media ID byte (see #01356)
  
 ===== Notes ===== ===== Notes =====
  
- under DOS 1.x, DS:BX points at an actual copy of the FAT; later +under DOS 1.x, DS:BX points at an actual copy of the FAT; later versions return a pointer to a copy of the FAT's ID byte 
-          versions return a pointer to a copy of the FAT's ID byte + 
-        this function may not be properly supported on CD-ROMs and other +this function may not be properly supported on CD-ROMs and other installable file systems (use AX=4402h"CD-ROM" for CD-ROMs instead) 
-          installable file systems (use AX=4402h"CD-ROM" for CD-ROMs + 
-          instead) +BUG:    DOS 7.10 (Win95B/Win98) reportedly returns incorrect values in AL and DX for FAT12/FAT16 drives, even though it manages correct results for FAT32 drives (DOS windows are not affected, only real-mode DOS)
-BUG:    DOS 7.10 (Win95B/Win98) reportedly returns incorrect values in AL and +
-          DX for FAT12/FAT16 drives, even though it manages correct results +
-          for FAT32 drives (DOS windows are not affected, only real-mode +
-          DOS)+
  
 Values for media ID byte: Values for media ID byte:
- FFh    floppy, double-sided, 8 sectors per track (320K) + 
- FEh    floppy, single-sided, 8 sectors per track (160K) +| FFh  | floppy, double-sided, 8 sectors per track (320K) | 
- FDh    floppy, double-sided, 9 sectors per track (360K) +| FEh  | floppy, single-sided, 8 sectors per track (160K) | 
- FCh    floppy, single-sided, 9 sectors per track (180K) +| FDh  | floppy, double-sided, 9 sectors per track (360K) | 
- FAh    HP 200LX D: ROM disk, 16 sectors per track (995K) +| FCh  | floppy, single-sided, 9 sectors per track (180K) | 
-        HP 200LX E: (Stacker host drive ???) +| FAh  | HP 200LX D: ROM disk, 16 sectors per track (995K) HP 200LX E: (Stacker host drive ???) | 
- F9h    floppy, double-sided, 15 sectors per track (1.2M) +| F9h  | floppy, double-sided, 15 sectors per track (1.2M) floppy, double-sided, 9 sectors per track (720K,3.5") | 
-        floppy, double-sided, 9 sectors per track (720K,3.5") +| F8h  | hard disk | 
- F8h    hard disk +| F0h  | other media (e.g. floppy, double-sized, 18 sectors per track -- 1.44M,3.5") |
- F0h    other media +
-        (e.g. floppy, double-sized, 18 sectors per track -- 1.44M,3.5")+
                      
 ===== See also ===== ===== See also =====
  
-AH=1Ch,AH=36h+AH=[[en:docs:dos:api:int21:1c|1Ch]],AH=[[en:docs:dos:api:int21:36|36h]]
  
 ===== Note ===== ===== Note =====