Acorp 4D533 User Manual page 34

MAINBOARD BIOS SETUP
☆ IDE Primary/Secondary Master/Slave
This is where you will specify the type of device and how it is represented in the BIOS Setup. If
the device is a hard disk or CD-ROM, generally the Auto option is the best choice for fast and
easy setup of the hard disk parameters. Let's take a look at the difference between the Auto
and Manual options:
"
Auto
This option instructs the BIOS to automatically configure the hard disk by reading the
parameters (cylinders, sectors, etc.) directly from the hard disk's firmware. Use this
option if you are configuring a new hard drive, or one that has already been formatted
using the Auto option. Keep in mind that a hard drive is configured using a certain set
of parameters, those same parameters must be used for the life of the drive, unless
the drive is re-FDISKed using a different parameter set. (This procedure deletes the
old partition(s) on the drive and creates a new one, using the new parameters).
"
Manual
This option allows you to manually enter in the parameters (cylinder, head, precomp,
landing zone and sector) of the hard drive. Generally, this option would be used only
if the hard drive has already been formatted with a certain set of parameters, and
assured consistency between the old and new parameters is desired.
☆ Access Mode
• One of Enhanced IDE's most important features is LBA (Logical Block Addressing) Mode.
This feature allows the use of larger hard drives by providing a way to bypass the cylinder
limitations imposed by many Operating Systems. LBA Mode is used to extend a hard drive's
useable capacity by remapping the cylinders in a way that is acceptable to these operating
systems. For instance, a hard drive with the parameters of 2100 Cylinders, 16 Heads and 63
Sectors would be represented by LBA Mode as 525 Cylinders, 64 Heads and 63 Sectors.
(Notice that the Cylinders have been divided, and the Heads have been multiplied, by a
factor of 4.)
• On hard drives smaller in capacity than 528MB, LBA support is not needed. The option
on these devices is ignored, even if enabled. For hard drives greater than 528MB, LBA
mode should be enabled. The following rules apply:
• Operating Systems that do not use the FAT file system do not need LBA Mode, and
can use the Normal or Large Modes. Examples would be NetWare and Unix.
34
User's Manual