INT 13 - SWBIOS - GET EXTENDED CYLINDER COUNT
AH = FEh
DL = drive number (80h, 81h)
Return: CF clear
DX = number of cylinders beyond 1024 on drive
Notes:  standard INT 13/AH=08h will return a cylinder count truncated to 1024
BIOS without this extension would return count modulo 1024
SWBIOS is a TSR by Ontrack Computer Systems; Disk Manager also supports
these calls

See also: 13EE

13FE - SWBIOS - GET EXTENDED CYLINDER COUNT