User`s guide

MegaRUM II PCI Motherboard User’s Guide

Standard Setup, Continued

Entering Drive Parameters You can also enter the hard disk drive

parameters. The drive parameters are:

Parameter Description

Type The number for a drive with certain identification

parameters.

Size The formatted size of the drive is the number of heads

times the number of cylinders times the number of

sectors per track times 512 (bytes per sector).

Cylinders The number of cylinders in the disk drive.

Heads The number of heads.

Write

Precompensation

The actual physical size of a sector gets progressively

smaller as the track diameter diminishes. Yet each sector

must still hold 512 bytes. Write precompensation

circuitry on the hard disk compensates for the physical

difference in sector size by boosting the write current for

sectors on inner tracks. This parameter is the track

number on the disk surface where write precompensation

begins.

Landing Zone This number is the cylinder location where the heads

normally park when the system is shut down.

Sectors The number of sectors per track. MFM drives have 17

sectors per track. RLL drives have 26 sectors per track.

ESDI drives have 34 sectors per track. SCSI and IDE

drives have even more sectors per track.

LBA Mode LBA (Logical Block Addressing) is a method of

addressing data on a disk drive. In LBA mode, the

maximum drive capacity is 8.4GB.

Blk Mode Block mode boosts IDE drive performance by increasing

the amount of data transferred. Only 512 bytes of data

can be transferred per interrupt if block mode is not used.

Block mode allows transfers of up to 64 KB per

interrupt.

PIO Mode IDE PIO mode programs timing cycles between the IDE

drive and the programmable IDE controller. As the PIO

mode increases, the cycle time decreases.

32Bit Mode Hard disk drives connected to the computer via the ISA

bus transfer data 16 bits at a time. An IDE drive on the

PCI bus or VL-Bus can use a 32-bit data path.

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