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 | Appendix A: BIOS POST Codes | 
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| POST Code | Description | 
| 5Ch | Test RAM between 512 and 640 kB | 
| 60h | Test extended memory | 
| 62h | Test extended memory address lines | 
| 64h | Jump to UserPatch1 | 
| 66h | Confi gure advanced cache registers | 
| 67h | Initialize Multi Processor APIC | 
| 68h | Enable external and CPU caches | 
| 69h | Setup System Management Mode (SMM) area | 
| 6Ah | Display external L2 cache size | 
| 6Bh | Load custom defaults (optional) | 
| 6Ch | Display  | 
| 6Eh | Display possible high address for UMB recovery | 
| 70h | Display error messages | 
| 72h | Check for confi guration errors | 
| 76h | Check for keyboard errors | 
| 7Ch | Set up hardware interrupt vectors | 
| 7Dh | Initialize Intelligent System Monitoring | 
| 7Eh | Initialize coprocessor if present | 
| 80h | Disable onboard Super I/O ports and IRQs | 
| 81h | Late POST device initialization | 
| 82h | Detect and install external RS232 ports | 
| 83h | Confi gure  | 
| 84h | Detect and install external parallel ports | 
| 85h | Initialize  | 
| 86h | |
| 87h | Confi gure Motherboard Confi gurable Devices (optional) | 
| 88h | Initialize BIOS Data Area | 
| 89h | Enable  | 
| 8Ah | Initialize Extended BIOS Data Area | 
| 8Bh | Test and initialize PS/2 mouse | 
| 8Ch | Initialize fl oppy controller | 
| 8Fh | Determine number of ATA drives (optional) | 
| 90h | Initialize  | 
| 91h | Initialize  | 
| 92h | Jump to UserPatch2 | 
| 93h | Build MPTABLE for  | 
| 95h | Install CD ROM for boot | 
| 96h | Clear huge ES segment register | 
| 97h | Fix up Multi Processor table | 
| 98h | |
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 | checksum failure | 
