Sunday, 16 November 2008 13:36

Bios Limitations

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Systems with BIOS dated prior to July 1994(504 MB Limitation).

Typically these BIOS will have a 504 megabyte (1,024 cylinder) limitation. Prior to this date, most manufacturers' BIOS did not provide the Logical Block Address (LBA) feature needed for proper translation. Some BIOS had LBA mode in the setup, but the feature did not work properly.

 

Systems with BIOS dated after July of 1994 (2.048 GB Limitation).

Typically, these BIOS provide support for hard drives with capacities larger than 504 megabytes. However, depending on the manufacturer's release date and version number, different limitations may be encountered. The major limitation that surfaces is the 4,093-4,096 cylinder limitation. This barrier is derived from the fact that some BIOS manufacturers implemented Logical Block Addressing (LBA) translation in their BIOS with a 4,093 - 4,096 cylinder limitation. System hangs would occur when the cylinder limitation threshold is exceeded. A system hang is defined when the operating system hangs during initial loading, either from floppy diskette or existing hard drives. If these symptoms of system hang occur or there are questions whether the system BIOS will support the drive, contact the system or motherboard manufacturer for assistance.

 

4.2 GB Limitation.

The maximum parameters at the 4.2 GB barrier are 8,190 cylinders, 16 heads and 63 sectors for a capacity of 4.2 GB. A system hang is defined when the operating system stops responding during initial loading, either from floppy diskette or existing hard drives. This can be caused by the BIOS reporting the number of heads to the operating system as 256 (100h). The register size DOS/Windows 95 uses for the head count has a capacity of two hex digits. This is equivalent to decimal values 255. If these symptoms of system hang occur or there are questions whether the system BIOS will support the drive, contact the system or motherboard manufacturer for assistance.

 

8.4 GB limitation.

The maximum parameters at the 8.4 GB barrier are 16,383 cylinders, 16 heads and 63 sectors for a capacity of 8.455 GB. To go beyond this boundary, a new extended INT 13 function is needed from the BIOS as a support feature for the drives. The BIOS listed below are all "CORE" BIOS that will support drives larger than 8.4 GB. Even though a BIOS is dated correctly or is the current version, it may not be able to support extended interrupt 13 because of modification done to the "CORE" of the BIOS from the motherboard manufacturer.

 

32 GB limitation.

This condition is caused by the Award BIOS inability to address hard drives greater than 32GB. Award has been made aware of this issue and has fixed their "core" BIOS as of 6/99. They are passing this information along to the motherboard manufacturers' that use their BIOS. Updates for the BIOS should be available soon from individual motherboard manufacturers' to correct this problem. The following are options to overcome this hang condition: Please contact your motherboard manufacturer, not Award, for a BIOS update. If your motherboard manufacturer does not have an update available, purchase the Maxtor Ultra ATA 100 adapter as an alternative solution. Maxtor Ultra ATA 100 "Where to Buy"


Install the Capacity limitation jumper (J46) and use the Maxblast Plus installation software to complete the installation. Please refer to hard drive Installation Instructions for location of this jumper or click here for an illustration of jumper locations. If your system still hangs after installing the J46 jumper, please run the file JUMPON.EXE. Note: If the BIOS is believed to fall within the following guidelines but does not support the drive, contact the system or motherboard manufacturer for a potential upgrade to their product.


American Megatrends INC. (AMI): BIOS versions with a date of January 1, 1998 or newer. Award: BIOS versions dated November 1997 or newer. Phoenix: Version 4 Revision 6 or newer. Note: Maxtor hard drives have a Cylinder Limitation Jumper to assist in the resolution of BIOS limitation issues. When this jumper is installed the MaxBlast Software must be used to complete the installation of the hard drive. Some Operating Systems will NOT function properly when the Capacity Limitation Jumper is applied (e.g., Windows NT, Linux, etc.).

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