QDI Brilliant IV, Руководство пользователя

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Chapter 7
51
2.
HDD Modes
The Award BIOS supports 3 HDD modes: NORMAL, LBA and LARGE,
also Auto detect.
NORMAL
Generic access mode in which neither the BIOS nor the IDE controller
will make any transformation during accessing. The maximum number of
cylinders, heads and sectors for NORMAL mode are 1024,16 and 63.
If the user sets his HDD to NORMAL mode,the maximum accessible
HDD size will be 528 megabytes even though its physical size may be
greater than that.
LBA (Logical Block Addressing) mode
A new HDD accessing method to overcome the 528 Megabyte bottleneck.
The number of cylinders, heads and sectors shown in setup may not be
the number physically contained in the HDD.
During HDD accessing, the IDE controller will transform the logical
address described by the sector, head and cylinder number into its
own physical address inside the HDD. The maximum HDD size
supported by LBA mode is 8.4 Gigabytes.
LARGE mode
Some IDE HDDs contain more than 1024 cylinder without LBA support
(in some cases, users do not want LBA). The Award BIOS provides
another alternative to support these kinds of HDD.
BIOS tricks DOS (or other OS) that the number of cylinders is less than
1024 by dividing it by 2. At the same time, the number of heads is multiplied
by 2. A reverse transformation process will be made inside INT13h in order to
access the right HDD address.
Auto detect
If using Auto detect, the BIOS will automatically detect IDE hard disk
mode and set it to one kind of HDD modes.
3.
Remark
To support LBA or LARGE mode of HDDs, there must be some software
involved which are located in Award HDD Service Routine(INT13h).It
may fail to access a HDD with LBA (LARGE) mode selected if you are
running under an Operating System which replaces the whole INT 13h.