Tag Archives: Legacy

Floppy 3 Mode Support – The BIOS Optimization Guide

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Floppy 3 Mode Support

Common Options : Disabled, Drive A, Drive B, Both

 

Quick Review

For reasons best known to the Japanese, their computers come with special 3 mode 3.5″ floppy drives. While physically similar to the standard 3.5″ floppy drives used by the rest of the world, these 3 mode floppy drives differ in the disk formats they support.

Unlike normal floppy drives, 3 mode floppy drives support three different floppy disk formats – 1.44 MB, 1.2 MB and 720 KB. Hence, their name. They allow the system to support the Japanese 1.2 MB floppy disk format, as well as the standard 1.44 MB and 720 KB (obsolete) disk formats.

If you own a 3 mode floppy drive and need to use the Japanese 1.2 MB disk format, you must enable this feature by selecting either Drive A, Drive B or Both (if you have two 3 mode floppy drives). Otherwise, your 3 mode floppy drive won’t be able to read the special 1.2 MB format properly.

However, if you only have a standard floppy drive, you must disable the Floppy 3 Mode Support feature or your floppy drive may not function properly.

 

Details

For reasons best known to the Japanese, their computers come with special 3 mode 3.5″ floppy drives. While physically similar to the standard 3.5″ floppy drives used by the rest of the world, these 3 mode floppy drives differ in the disk formats they support.

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Unlike normal floppy drives, 3 mode floppy drives support three different floppy disk formats – 1.44 MB, 1.2 MB and 720 KB. Hence, their name. They allow the system to support the Japanese 1.2 MB floppy disk format, as well as the standard 1.44 MB and 720 KB (obsolete) disk formats.

If you own a 3 mode floppy drive and need to use the Japanese 1.2 MB disk format, you must enable this feature by selecting either Drive A, Drive B or Both (if you have two 3 mode floppy drives). Otherwise, your 3 mode floppy drive won’t be able to read the special 1.2 MB format properly.

However, if you only have a standard floppy drive, you must disable the Floppy 3 Mode Support feature or your floppy drive may not function properly.

 

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PCI Prefetch – The BIOS Optimization Guide

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PCI Prefetch

Common Options : Enabled, Disabled

 

Quick Review

The PCI Prefetch feature controls the PCI controller’s prefetch capability.

When enabled, the PCI controller will prefetch data whenever the PCI device reads from the system memory. This speeds up PCI reads as it allows contiguous memory reads by the PCI device to proceed with minimal delay.

Therefore, it is recommended that you enable this feature for better PCI read performance.

 

Details

The PCI Prefetch feature controls the PCI controller’s prefetch capability.

When enabled, the system controller will prefetch eight quadwords (one cache line) of data whenever a PCI device reads from the system memory.

Therefore, it is recommended that you enable this feature for better PCI read performance. Please note that PCI writes to the system memory do not benefit from this feature.

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Here’s how it works.

Whenever the PCI controller reads PCI-requested data from the system memory, it also reads the subsequent cache line of data. This is done on the assumption that the PCI device will request for the subsequent cache line.

When the PCI device actually initiates a read command for that cache line, the system controller can immediately send it to the PCI device.

This speeds up PCI reads as the PCI device won’t need to wait for the system controller to read from the system memory. As such, PCI Prefetch allows contiguous memory reads by the PCI device to proceed with minimal delay.

 

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If you like our work, you can help support our work by visiting our sponsors, participating in the Tech ARP Forums, or even donating to our fund. Any help you can render is greatly appreciated!