PC/104-Plus – CPU-1461 Module | 37 |
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PIO Mode
PIO is a special data-transfer system between two or more EIDE devices, where all the data pass through the processor. There are five transfer rates, called PIO mode n (with n=0..4). If the Auto (autodetect) option is disabled, the PIO mode must be specified.
Option | Description | Note |
PIO-0 | Transfer Rate of 3.3 MBps | |
PIO-1 | Transfer Rate of 5.2 MBps | |
PIO-2 | Transfer Rate of 8.3 MBps | |
PIO-3 | Transfer Rate of 11.1 MBps | |
PIO-4 | Transfer Rate of 16.6 MBps | |
Translation Mode
Modern hard-disks have more cylinders than maximum number of cylinders permitted by DOS, so, theoretically, a DOS machine couldn’t use a modern big-sized hard disk. This problem is solved using a special addressing mechanism. This “mechanism” is called translation. The most common translation method are LBA (Logical Block Addressing) and ECHS (Enhanced Cylinders - Heads - Sectors).
Option | Description | Note |
LBA | LBA translation | |
ECHS | Extended CHS translation | |
Cylinders
Number of hard-disk cylinders (normally written on the disk label). If the auto-detection is used (suggested method!), the cylinders value is ignored by the BIOS.
Option | Description | Note |
0..65536 | Number of cylinders | |
Heads
Number of hard-disk heads (normally written on the disk label). If the auto-detection is used (suggested method!), the heads value is ignored by the BIOS.
Option | Description | Note |
0..64 | Number of heads | |
Sect/Tr
Number of sectors per track (normally written on the disk label). If the auto-detection is used (suggested method!), the sectors value is ignored by the BIOS.
Option | Description | Note |
0..255 | Number of sectors per track | |
Size (MB)
This is the hard-disk size, in Mbytes, calculated by the BIOS, using either the autodetect method or the user hand-written values (for cylinders, heads and sectors).
•Note: the size cannot be changed directly by the user.
