Yamaha LSI YMF715 User Manual download pdf (Page 30)

AWARD BIOS 3-19

LBA (Logical Block Addressing) mode: This is a new HDD accessing method to

overcome the 528 Megabyte bottleneck.

The number of cylinders, heads and sectors shown in the setup may not be the number

physically contained in the HDD.

During the HDD accessing, the IDE controller will transform the logical address

described by sector, head and cylinder into its own physical address inside the HDD.

The maximum HDD size supported by LBA mode is 8.4 Gigabytes which is

obtained by the following formula:

no. Cyclinder (1024)

x no. Head ( 255)

x no. Sector ( 63)

x bytes per secttor ( 512)

8.4 Gigabytes

LARGE mode: This is an extended HDD access mode supported by Award Software.

Some IDE HDDs contain more than 1024 cylinders without LBA support (in some

cases, user does not want LBA). The Award BIOS provides another alternative to

support these kinds of LARGE mode:

CYLS. HEADS SECTOR MODE

1120 16 59 NORMAL

560 32 59 LARGE

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 INT 12h in order to access the right

HDD address

Maximum HDD size:

no. Cyclinder (1024)

x no. Head ( 32)

x no. Sector ( 63)

x bytes per sector ( 512)

1 Gigabytes

1 2 ... 25 26 27 28 29 30 31 32 33 34 35 ... 42 43

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Yamaha LSI YMF715 User Manual Page 30