The output of this function is defined as follows:Register FunctionAH Status of OperationDL 00h - Drive not present or invalid DL03h - Fixed Disk Present01h, 02h - ReservedCX Number of blocks on diskCF Return CodeThe following function codes are not supported by the AHA-1740A/1742A BIOS:(AH) = 05h Format Desired Cylinder(AH) = 06h Format Desired Cylinder and Set Bad Sector Flags(AH) = 07h Format Drive Starting at Desired Cylinder(AH) = 0Ah Reserved(AH) = 0Bh Reserved(AH) = 0Eh Reserved(AH) = 0Fh Reserved(AH) = 12h Reserved(AH) = 13h Reserved(AH) = 14h Reserved(AH) = 16h Reserved(AH) = 17h Reserved(AH) = 18h Reserved(AH) = 19h Park Heads(AH) = 1Ah Format Unit(AH) = 1Bh-FFhReservedAn invalid command error is returned for any of these function codes.Int 15h FunctionalityAfter issuing an I/O command to the host adapter, the AHA-1740A/1742A BIOS willmake use of the Int 15 Device Busy (function 90h) to inform the operating systemthat the BIOS is about to wait for a device.When the AHA-1740A/1742A interrupts indicating that the I/O is complete, an Inter-rupt Complete (function 91h) will be issued by the BIOS indicating that the wait iscomplete.Differences Between Operating Modes• VDS is supported in Enhanced Mode only• In EISA mode, the BIOS will scan for Int 13h devicesEISA-to-Fast SCSI Host Adapter Onboard BIOS Interface7-9
