June 23, 2010 |
8.26 Set Hardware Configuration (FN 4Eh)
The purpose of this function is to allow
Entry |
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| AH 4Eh |
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| AL | Hardware configuration | |
| DL BIOS device number | ||
Exit |
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| Carry Clear | Function completed without error | |
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| AH | Shall be cleared to zero |
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| AL | 00h if command was safe, 01h if other devices are affected |
| Carry Set | Function completed with an error | |
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| AH | Shall be set to the error code |
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| Table 29 — Hardware Configuration | |
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AL |
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| Description |
0h | Enable prefetch |
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1h | Disable prefetch |
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2h | Set maximum PIO transfer mode. | ||
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3h | Set PIO mode 0. |
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4h | Return to default PIO transfer mode. Return the system to the PIO mode enabled by the BIOS setup | ||
| utility. |
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5h | Enable INT 13h DMA maximum mode. Set the maximum rate allowed by both the host adapter and the | ||
| device. |
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6h | Disable INT 13h DMA |
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Working Draft Enhanced Disk Drive - 4 | 65 |