MAINBOARD BIOS SETUP
MAINBOARD BIOS SETUP
User’s Manual
User’s Manual
23
23
disk parameters. Let’s take a look at the difference between the
Auto
,
User
and
Types (1-
45)
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).
•
User
- This option allows you to manually
enter in the parameters 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.
•
Types 1-45
- Similar to the
User
option, these types should only be used if the exact
parameters for the hard drive are already entered as a specific type stored in the Setup
Program. Again, this would only be needed to assure that the parameters the drive was
formatted with and those it is using now, are identical. For new hard drives, the
Auto
option is the preferred choice.
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.
•
When configuring a new hard drive greater than 528MB in capacity, always make sure
LBA mode is enabled.
•
If you are using a hard drive that is over 528MB in capacity, but was already formatted
without using LBA mode, LBA support will be ignored even if it is enabled. This
assures correct access to the drive’s data.
TYPE
drive type
CYLS.
number of cylinders
HEADS
number of heads
PRECOMP
write precom
LANDZONE
landing zone
SECTORS
number of sectors
MODE
mode type
