![](/images/new-backgrounds/1266758/266758311x1.webp)
Code | Beeps | POST Routine Description |
|
|
|
8Bh |
| Test and initialize PS/2 mouse |
|
|
|
8Ch |
| Initialize floppy 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 |
| Fixup Multi Processor table |
|
|
|
98h | Search for option ROMs. One long, two short beeps on checksum failure. | |
|
|
|
99h |
| Check for SMART drive (optional) |
|
|
|
9Ah |
| Shadow option ROMs |
|
|
|
9Ch |
| Set up Power Management |
|
|
|
9Dh |
| Initialize security engine (optional) |
|
|
|
9Eh |
| Enable hardware interrupts |
|
|
|
9Fh |
| Determine number of ATA and SCSI drives |
|
|
|
A0h |
| Set time of day |
|
|
|
A2h |
| Check key lock |
|
|
|
A4h |
| Initialize Typematic rate |
|
|
|
A8h |
| Erase F2 prompt |
|
|
|
AAh |
| Scan for F2 key stroke |
|
|
|
ACh |
| Enter SETUP |
|
|
|
AEh |
| Clear Boot flag |
|
|
|
B0h |
| Check for errors |
|
|
|
B2h |
| POST done- prepare to boot operating system |
|
|
|
B4h | 1 | One short beep before boot |
|
|
|
B5h |
| Terminate QuietBoot (optional) |
|
|
|
B6h |
| Check password (optional) |
|
|
|
B9h |
| Prepare Boot |
|
|
|
BAh |
| Initialize DMI parameters |
|
|
|
BBh |
| Initialize PnP Option ROMs |
|
|
|
BCh |
| Clear parity checkers |
|
|
|
BDh |
| Display MultiBoot menu |
|
|
|
BEh |
| Clear screen (optional) |
|
|
|
BFh |
| Check virus and backup reminders |
|
|
|
C0h |
| Try to boot with INT 19 |
|
|
|
C1h |
| Initialize POST Error Manager (PEM) |
|
|
|
C2h |
| Initialize error logging |
|
|
|
C3h |
| Initialize error display function |
|
|
|
C4h |
| Initialize system error handler |
|
|
|
C5h |
| PnPnd dual CMOS (optional) |
|
|
|
C6h |
| Initialize notebook docking (optional) |
|
|
|
146 | Chapter 4: Troubleshooting |