INT 13H (0x13) Function EFH (0xEF or 239) Set Cylinder Offset (Ontrack Drive Rocket) F9H (0xF9 or 249) Installation Check FEH (0xFE or 254) Get Extended Cylinder Count (SWBIOS) FFH (0xFF or 255) Officially Private Function (IBM SurePath BIOS) FFFFH (0xFFFF) Set Turbo Mode (UNIQUE UX Turbo Utility)

INT 13H (0x13)

Function EFH (0xEF or 239) --> Set Cylinder Offset (Ontrack Drive Rocket)

Call with: AH = EFH
CX = Cylinder offset for next INT 13H call
DL = Drive Number

Return:
Carry Flag = Clear
AH = 00H

Comments:

The Function is used to set Cylinder offset. For software which supports this call, the Function AH=EEH is equivalent to calling this function with CX=0400H. The cylinder offset is reset to 0 by all INT 13H called except AH=EEH and AH=EFH.

INT 13H (0x13)

Function F9H (0xF9 or 249) --> Installation Check (SWBIOS)

Call with: AH = F9H
DL = Drive Number

Return: If Function Successful,
Carry Flag = Clear
DX = Configuration Word (see comments)

If Function Unsuccessful,
Carry Flag = Set

Comments:

This Function is used for installation Check. If the Function is successful carry flag is clear and DX returns the configuration word, else carry flag is set.

Bit 15 is set if other SWBIOS extensions are available. Disk Manager also supports these calls.

INT 13H (0x13)

Function FEH (0xFE or 254) --> Get Extended Cylinder Count (SWBIOS)

Call with: AH = FEH
DL = Drive Number

Return:
Carry Flag = Clear
DX = Number of Cylinders beyond 1024
on drive

Comments:

This function is used to get the extended Cylinder count. The function AH = 08H of INT 13H will return a cylinder count truncated to 1024. BIOS without this extension would return count modul 1024. Disk Manager also supports these calls

INT 13H (0x13)

Function FFH (0xFF or 255) --> Officially Private Function (IBM SurePath BIOS)

INT 13H (0x13)

Function FFFFH (0xFFFF) --> Set Turbo Mode (UNIQUE UX Turbo Utility)

Call with: AX = FFFFH
BH = AAH
BL = Sub Function Number (See the table
in Comments)
Return: If installed,
AX = 1234H

Comments:

This function is used to set the Turbo Mode. The Sub function numbers to call the function with BL have been given in the following table:

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