BIOS POST Codes

Verify real mode

Disable non-maskable interrupt (NMI)

Get CPU type

Initialize system hardware

Disable shadow and execute code from the ROM

Initialize chipset with initial POST values

Set IN POST flag

Initialize CPU registers

Enable CPU cache

Initialize caches to initial POST values

Initialize I/O component

Initialize the local bus IDE

Initialize power management

Load alternate registers with initial POST values

Restore CPU control word during warm boot

Initialize PCI bus mastering devices

Initialize keyboard controller

BIOS ROM checksum

Initialize cache before memory autosize

8254 programmable interrupt timer initialization

8237 DMA controller initialization

Reset programmable interrupt controller

Test DRAM refresh

Test 8742 keyboard controller

Set ES segment register to 4 GB

Enable gate A20 line

Autosize DRAM

Initialize POST memory manager

Clear 512 KB base RAM

RAM failure on address line xxxx

RAM failure on data bits xxxx of low byte of memory bus

Enable cache before system BIOS shadow

RAM failure on data bits xxxx of high byte of memory bus

Test CPU bus clock frequency

Initialize Phoenix Dispatch Manager

Warm start shut down

Shadow system BIOS ROM

Autosize cache

Advanced configuration of chipset registers

Load alternate registers with CMOS values

Initialize extended memory for RomPilot

Initialize interrupt vectors

POST device initialization

Check ROM copyright notice

Initialize I20 support

Check video configuration against CMOS

Initialize PCI bus and devices

Initialize all video adapters in system

QuietBoot start (optional)

Shadow video BIOS ROM

Display BIOS copyright notice

Initialize MultiBoot

Display CPU type and speed

Initialize EISA board

Test keyboard

Set key click if enabled

Enable USB devices

Test for unexpected interrupts

Initialize POST display service

Display prompt “Press F2 to enter SETUP”

Disable CPU cache

Test RAM between 512 KB and 640 KB

Test extended memory

Test extended memory address lines

Jump to UserPatch1

Configure advanced cache registers

Initialize multiprocessor APIC

Enable external and CPU caches

Set up system management mode (SMM) area

Display external L2 cache size

Load custom defaults (optional)

Display shadow area message

Display possible high address for UMB recovery

Display error messages

Check for configuration errors

Check for keyboard errors

Set up hardware interrupt vectors

Initialize Intelligent System Monitoring

Initialize coprocessor if present

Disable on-board super I/O ports and IRQs

Late POST device initialization

Detect and install external RS-232 ports

Configure non-MCD IDE controllers

Detect and install external parallel ports

Initialize PC compatible PnP ISA devices

Reinitialize on-board I/O ports

Configure motherboard configurable devices (optional)

Initialize BIOS data area

Enable non-maskable interrupts (NMIs)

Initialize extended BIOS data area

Test and initialize PS/2 mouse

Initialize floppy controller

Determine number of ATA drives (optional)

Initialize hard disk controllers

Initialize local bus hard disk controllers

Jump to UserPatch2

Build MPTABLE for multiprocessor boards

Install CD-ROM for boot

Clear huge ES segment register

Fix up multiprocessor table

Search for option ROMs

Check for SMART drive (optional)

Shadow option ROMs

Set up power management

Initialize security engine (optional)

Enable hardware interrupts

Determine number of ATA and SCSI drives

Set time of day

Check key lock

Initialize typematic rate

Erase F2 prompt

Scan for F2 keystroke

Enter setup

Clear boot flag

Check for errors

Inform RomPilot about the end of POST

POST done - prepare to boot operating system

One short beep

Terminate QuietBoot (optional)

Check password

Initialize ACPI BIOS

Prepare boot

Initialize DMI parameters

Initialize PnP option ROMs

Clear parity checkers

Display multiboot menu

Clear screen

Check virus and backup reminders

Try to boot with interrupt 19

Initialize POST Error Manager (PEM)

Initialize error logging

Initialize error display function

Initialize system error handler

PnP dual CMOS (optional)

Initialize notebook docking (optional)

Initialize notebook docking late

Force check (optional)

Extended checksum (optional)

Redirect Int 15h to enable remote keyboard

Redirect Int 13 to Memory Technologies Devices such as ROM, RAM, PCMCIA and serial disk

Redirect Int 10h to enable remote serial video

Remap I/O and memory for PCMCIA

Initialize digitizer and display message

Unknown interrupt

Initialize the chipset

Initialize the bridge

Initialize the CPU

Initialize the system timer

Initialize system I/O

Check force recovery boot

Checksum BIOS ROM

Go to BIOS

Set Huge Segment

Initialize multiprocessor

Initialize OEM special code

Initialize PIC and DMA

Initialize memory type

Initialize memory size

Shadow boot block

System memory test

Initialize interrupt vectors

Initialize run time clock

Initialize video

Initialize System Management Manager

Output one beep

Clear huge segment

Boot to mini DOS

Boot to Full DOS