Appendix B:
BIOS POST Codes 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 Configure 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 shadow-area message 70h Display error messages 72h Check for configuration errors 76h Check for keyboard errors 7Ch Set up hardware interrupt vectors 7Dh Initialize Intelligent System Monitoring (optional) 7Eh Initialize coprocessor if present 80h Disable onboard Super I/O ports and IRQs (optional) 81h Late POST device initialization 82h Detect and install external RS232 ports 83h Configure non-MCD IDE controllers 84h Detect and install external parallel ports 85h Initialize PC-compatible PnP ISA devices 86h Re-initialize onboard I/O ports.
87h Configure Motherboard Configurable Devices (optional) 88h Initialize BIOS Data Area 89h Enable Non-Maskable Interrupts (NMIs) 8Ah Initialize Extended BIOS Data Area 8Bh Test and initialize PS/2 mouse 8Ch Initialize floppy controller 8Fh Determine number of ATA drives (optional) 90h Initialize hard-disk controllers 91h Initialize local-bus hard-disk controllers 92h Jump to UserPatch2 93h Build MPTABLE for multi-processor boards 95h Install CD ROM for boot 96h Clear huge ES segment register 97h Fix up Multi Processor table 98h 1-2 Search for option ROMs and shadow if successful. One long, two short beeps on checksum failure B-3