Codici errore del BIOS
Alcune schede madri permettono l’individuazione degli errori hardware tramite un display a 2 caratteri, questi codici possono semplificare l’individuazione e la risoluzione dei problemi.
Tabella ACER
| 04 | CPU verification; POST start | 
| 08 | Shutdown condition 0; Shutdown byte 0 | 
| 0C | BIOS ROM checksum tested | 
| 10 | CMOS ROM shutdown byte tested | 
| 14 | DMA controller tested | 
| 18 | System timer initialized | 
| 1C | Memory refresh system tested | 
| 1E | Memory type determined | 
| 20 | Base 128K memory tested | 
| 24 | 8042 keyboard controller tested | 
| 28 | CPU descriptor instruction tested | 
| 2C | 8259 PIT tested | 
| 30 | Temporary Interrupts located and initialized | 
| 34 | BIOS Interrupt vectors and routines configured | 
| 38 | CMOS RAM tested | 
| 3C | Memory size determined | 
| 40 | Shutdown condition 1 | 
| 44 | Video BIOS ROM initialized | 
| 45 | RAM initialized and tested | 
| 46 | Cache memory and controller initialized and tested | 
| 48 | Memory tested | 
| 4C | Shutdown condition 3 | 
| 50 | Shutdown condition 2 | 
| 54 | Shutdown condition 7 | 
| 58 | Shutdown condition 6 | 
| 5C | Keyboard and auxiliary I/O tested | 
| 60 | BIOS Interrupt routines setup | 
| 64 | RTC tested | 
| 68 | Floppy drive and controller tested | 
| 6C | Hard drive and controller tested | 
| 70 | Parallel port tested | 
| 74 | Serial port tested | 
| 78 | Time of day setup | 
| 7C | Optional ROM’s searched for and started | 
| 80 | Math coprocessor tested | 
| 84 | Keyboard tested | 
| 88 | System initialized | 
| 8C | System initialized | 
| 90 | Operating system boot process started | 
| 94 | Shutdown condition 5 | 
| 98 | Shutdown condition A | 
| 9C | Shutdown condition B | 
Tabella ASUS
| POST code | What It Means | 
|---|---|
| 8 | CPU not detected | 
| 4B/FA | No DRAM detected/installed | 
| F9/0D | DRAM training failed | 
| 90/CF | DRAM recovery | 
| 06 | DRAM unstable | 
| A0-A2 | Boot up device unstable | 
| B2 | External device unstable | 
| D6 | Graphics card unstable | 
| AA | Boot into the system | 
Tabella Asrock
| POST Code | What It Means | 
|---|---|
| FF, 00 – 19/D0-D3 | Reseat Memory and then clear CMOS | 
| 31-3B/51-55 | Problem related to CPU and memory | 
| D4-D5 | PCI resource allocation error | 
| D6, 92-97 | Graphics card not recognized | 
| D7 | Keyboard not recognized | 
| 9A-9D | Problem related to USB devices | 
| 03 | System entering sleep | 
| AA | System is entering OS | 
Tabella Compaq
| 00 | Initialize flags, MSW,IDTLIN | 
| 01 | Read manufacturing jumper | 
| 02 | 8042 received read command | 
| 03 | No response from 8042 | 
| 04 | Look for ROM at E000 | 
| 05 | Look for ROM at C800 | 
| 06 | Normal CMOS reset code | 
| 08 | Initialize 8259,80287 | 
| 09 | Reset code in CMOS byte | 
| 0A | Vector vis 40:67 reset function | 
| 0B | Vector vis 40:67 with E01 function | 
| 0C | Boot reset function | 
| 0D | Test #2 8254 PIT counter 0 | 
| 0E | Test #2 8254 PIT counter 2 | 
| 0F | Warm boot | 
| 10 | PPI disabled, test 8254 PIT’s 0 and 1 | 
| 11 | Initialize (blast) VDU controller | 
| 12 | Clear screen; turn ON video | 
| 13 | Test time 0 | 
| 14 | Disable RTC interrupts | 
| 15 | Check battery power | 
| 16 | Battery has lost power | 
| 17 | Clear CMOS Diags. | 
| 18 | Test base memory (First 128K) | 
| 19 | Initialize base memory | 
| 1A | Initialize VDU adapters | 
| 1B | The system ROM | 
| 1C | CMOS checksum | 
| 1D | DMA controller/page registers | 
| 1E | Test keyboard controller | 
| 1F | Test 286 protected mode | 
| 20 | Test real and extended memory | 
| 21 | Initialize time-of-day | 
| 22 | Initialize 287 coprocessor | 
| 23 | Test the keyboard and 8042 | 
| 24 | Reset A20, set default CPU speed | 
| 25 | Test diskette subsystem | 
| 26 | Test fixed disk subsystem | 
| 27 | Initialize parallel printer | 
| 28 | Perform search for optional ROM’s | 
| 29 | Test valid system configuration | 
| 2A | Clear screen | 
| 2B | Check for invalid time and date | 
| 2C | Optional ROM search | 
| 2D | Test timer 2 | 
| 2F | Write to diagnostic byte | 
| 30 | Clear first 128K bytes of RAM | 
| 31 | Load interrupt vectors 70-77 | 
| 32 | Load interrupt vectors 00-1F | 
| 33 | Initialize MEMSIZE and RESETWD | 
| 34 | Verify CMOS checksum | 
| 35 | CMOS checksum is not valid | 
| 36 | Check battery power | 
| 37 | Check for game adapters | 
| 38 | Check for Serial ports | 
| 39 | Check for parallel printer ports | 
| 3A | Initialize port and comm time-outs | 
| 3B | Flush keyboard buffer | 
| 40 | Save RESETWD value | 
| 41 | Check RAM refresh | 
| 42 | Start write of 128K RAM test | 
| 43 | Reset parity checks | 
| 44 | Start verify of 128K RAM test | 
| 45 | Check for parity errors | 
| 46 | NO RAM errors | 
| 47 | RAM error detected | 
| 50 | Check for dual frequency in CMOS | 
| 51 | Check CMOS VDU configuration | 
| 52 | Start VDU ROM search | 
| 53 | Vector to VDU option ROM’s | 
| 54 | Initialize first display adapter | 
| 55 | Initialize second display adapter | 
| 56 | No display adapters installed | 
| 57 | Initialize primary VDU mode | 
| 58 | Start of VDU test (each adapter) | 
| 59 | Check existence of adapter | 
| 5A | Check VDU registers | 
| 5B | Start screen memory test | 
| 5C | End test of adapter, clear memory | 
| 5D | Error detected on an adapter | 
| 5E | Test the next adapter | 
| 5F | All adapters successfully tested | 
| 60 | Start of memory tests | 
| 61 | Enter protected mode | 
| 62 | Start memory sizing | 
| 63 | Get CMOS size | 
| 64 | Start test of real memory | 
| 65 | Start test of extended memory | 
| 66 | Save size memory (base, ext) | 
| 67 | 128K-option installed CMOS bit | 
| 68 | Prepare to return to real mode | 
| 69 | Back in real mode-successful | 
| 6A | Protected mode error during test | 
| 6B | Display error message | 
| 6C | End of memory test | 
| 6D | Initialize KB OK string | 
| 6E | Determine size to test | 
| 6F | Start MEMTEST | 
| 70 | Display XXXXXKB OK | 
| 71 | Test each RAM segment | 
| 72 | High order address test | 
| 73 | Exit MEMTEST | 
| 74 | Parity error on bus | 
| 75 | Start protected mode test | 
| 76 | Prepare to enter protected mode | 
| 77 | Test software exceptions | 
| 78 | Prepare to return to real mode | 
| 79 | Back in real mode-successful | 
| 7A | Back in real mode-error occurred | 
| 7B | Exit protected mode | 
| 7C | High order address test failure | 
| 7D | Entered cache controller test | 
| 7E | Programming memory cache | 
| 7F | Copy system ROM to high RAM | 
| 80 | Start of 8042 test | 
| 81 | Do 8042 self test | 
| 82 | Check result received | 
| 83 | Error result | 
| 84 | OK 8042, Init mode=5D | 
| 86 | Start test, reset keyboard | 
| 87 | Got acknowledge, read result | 
| 88 | Got result, check it | 
| 89 | Test for stuck keys | 
| 8B | Test keyboard interface | 
| 8A | Key seems to be stuck | 
| 8C | Got result, check it | 
| 8D | End of test, no errors | 
| 90 | Start of CMOS test | 
| 91 | CMOS seems to be OK | 
| 92 | Error on CMOS read,write test | 
| 93 | Start of DMA controller test | 
| 94 | Page registers seem to be OK | 
| 95 | DMA controller is OK | 
| 96 | 8237 initialization is complete | 
| 97 | Start of NCA RAM test | 
| A0 | Start of diskette tests | 
| A1 | FDC reset active (3F2h Bit 2) | 
| A2 | FDC reset inactive (3F2h Bit 2) | 
| A3 | FDC motor on | 
| A4 | FDC time-out error | 
| A5 | FDC failed reset | 
| A6 | FDC passed reset | 
| A8 | Start to determine drive type | 
| A9 | Seek operation initialized | 
| AA | Waiting for FDC seek status | 
| AF | Diskette tests complete | 
| B0 | Start of fixed drive tests | 
| B1 | Combo board not found-exit | 
| B2 | Combo controller failed-exit | 
| B3 | Testing drive 1 | 
| B4 | Testing drive 2 | 
| B5 | Drive error (error condition) | 
| B6 | Drive failed (failed to respond) | 
| B7 | No fixed drives-exit | 
| B8 | Fixed drive tests complete | 
| B9 | Attempt to boot diskette | 
| BA | Attempt to boot fixed drive | 
| BB | Boot attempt failed FD/HD | 
| BC | Jump to boot record | 
| BD | Drive error, retry booting | 
| BE | Weitek coprocessor test | 
| D0 | Entry to clear memory routine | 
| D1 | Ready to go to protected mode | 
| D2 | Ready to clear extended memory | 
| D3 | Ready to reset back to real mode | 
| D4 | Back in real mode | 
| D5 | Clear base memory | 
| DD | Built-in self-test failed | 
| E0 | Ready to replace E000 ROM | 
| E1 | Completed E000 ROM replacement | 
| E2 | Ready to replace EGA ROM | 
| E3 | Completes EGA ROM replacement | 
Tabella Dell
| 01 | CPU register test in progress | 
| 02 | CMOS read/write test failed | 
| 03 | BIOS ROM checksum bad | 
| 04 | 8254 programmable interrupt controller failed | 
| 05 | DMA controller initialization failed | 
| 06 | DMA page-register test failed | 
| 08 | RAM refresh verification failed | 
| 09 | Starting first-64K RAM test | 
| 0A | First-64KB RAM IC or data line bad | 
| 0B | First-64KB RAM odd/even logic bad | 
| 0C | First-64KB address line bad | 
| 0D | First-64KB parity error | 
| 10 | Bit 0 bad in first 64KB | 
| 11 | Bit 1 bad in first 64KB | 
| 12 | Bit 2 bad in first 64KB | 
| 13 | Bit 3 bad in first 64KB | 
| 14 | Bit 4 bad in first 64KB | 
| 15 | Bit 5 bad in first 64KB | 
| 16 | Bit 6 bad in first 64KB | 
| 17 | Bit 7 bad in first 64KB | 
| 18 | Bit 8 bad in first 64KB | 
| 19 | Bit 9 bad in first 64KB | 
| 1A | Bit 10 bad in first 64KB | 
| 1B | Bit 11 bad in first 64KB | 
| 1C | Bit 12 bad in first 64KB | 
| 1D | Bit 13 bad in first 64KB | 
| 1E | Bit 14 bad in first 64KB | 
| 1F | Bit 15 bad in first 64KB | 
| 20 | Slave DMA register bad | 
| 21 | Master DMA register bad | 
| 22 | Master interrupt-mask register bad | 
| 23 | Slave interrupt-mask register bad | 
| 25 | Loading interrupt vectors | 
| 27 | Keyboard-controller test failed | 
| 28 | CMOS RAM battery bad | 
| 29 | CMOS configuration validation in progress | 
| 2B | Video-memory test failed | 
| 2C | Video initialization failure | 
| 2D | Video-retrace failure | 
| 2E | Searching for a video ROM | 
| 30 | Switching to video ROM | 
| 31 | Monochrome operation OK | 
| 32 | Color (CGA) operation OK | 
| 33 | Color operation OK | 
| 34 | Timer-tick interrupt in progress (or bad) | 
| 35 | CMOS shutdown test in progress (or bad) | 
| 36 | Gate A20 bad | 
| 37 | Unexpected interrupt in protected mode | 
| 38 | RAM test in progress or high address line is bad | 
| 3A | Interval timer channel 2 bad | 
| 3B | Time-of-day test bad | 
| 3C | Serial-port test bad | 
| 3D | Parallel -port test bad | 
| 3E | Math co-processor test bad | 
| 3F | Cache-memory test bad | 
Tabella HP Pavillion
| 02 | Verify real mode | 
| 03 | Disable NMI | 
| 04 | Get processor type | 
| 06 | Initialize system hardware | 
| 08 | Initialize chipset with POST values | 
| 09 | Set IN-POST flags | 
| 0A | Initialize CPU registers | 
| 0B | Enable CPU registers | 
| 0C | Initialize cache to POST values | 
| 0E | Initialize I/O component | 
| 0F | Initialize local IDE bus | 
| 10 | Initialize power management | 
| 11 | Load alternate registers | 
| 12 | Restore CPU control word during warm boot | 
| 13 | Initialize PCI bus mastering devices | 
| 14 | Initialize keyboard controller | 
| 16 | BIOS ROM checksum | 
| 17 | Initialize cache before memory size | 
| 18 | Initialize 8254 timer | 
| 1A | Initialize DMA controller | 
| 1C | Reset PIC | 
| 20 | Test DRAM refresh | 
| 22 | Test 8742 keyboard controller | 
| 24 | Set ES segment register to 4GB | 
| 26 | Enable A-20 line | 
| 28 | Autosize DRAM | 
| 29 | Initialize POST memory manager | 
| 2A | Clear 512K base RAM | 
| 2C | RAM address line failure | 
| 2E | RAM data failure, low byte | 
| 2F | Enable cache before BIOS shadow | 
| 30 | RAM data failure, high byte | 
| 32 | Test CPU, BUS clock frequency | 
| 33 | Initialize POST dispatch manager | 
| 34 | Test CMOS RAM | 
| 35 | Initialize alternate chipset registers | 
| 36 | Warm start shut-down | 
| 37 | Reinitialize chipset (MB only) | 
| 38 | Shadow system BIOS ROM | 
| 39 | Reinitialize cache (MB only) | 
| 3A | Autosize cache | 
| 3C | Configure advanced chipset registers | 
| 3D | Load alternate registers new CMOS values | 
| 40 | Set initial CPU speed | 
| 42 | Initialize interrupts | 
| 44 | Initialize BIOS interrupts | 
| 45 | POST device initialization | 
| 46 | Check ROM copyright notice | 
| 47 | Initialize manager for PCI option ROM’s | 
| 48 | Check video config against CMOS | 
| 49 | Initialize manager for PCI option ROM’s | 
| 4A | Initialize all video adapters | 
| 4B | Display quiet boot screen | 
| 4C | Shadow video BIOS | 
| 4E | Display BIOS copyright notice | 
| 50 | Display CPU type & speed | 
| 51 | Initialize | 
| 52 | Test keyboard | 
| 54 | Set key click if enabled | 
| 56 | Enable keyboard | 
| 58 | Test for unexpected interrupts | 
| 59 | Initialize POST display service | 
| 5A | Display “Press F2 to Enter Setup” | 
| 5B | Disable CPU cache | 
| 5C | Test RAM, 512-640K | 
| 60 | Test extended memory | 
| 62 | Test extended memory address lines | 
| 64 | Jump to user patch 1 | 
| 66 | Configure advanced cache registers | 
| 67 | Initialize multi-processor APIC | 
| 68 | Enable external & processor caches | 
| 69 | Set up SMM area | 
| 6A | Display external L2 cache size | 
| 6C | Display shadow area message | 
| 6E | Display high address for UMB recovery | 
| 70 | Display error message | 
| 72 | Check for configuration errors | 
| 74 | Test real time clock | 
| 76 | Check for keyboard errors | 
| 7A | Test for key lock on | 
| 7C | Set up hardware interrupt vectors | 
| 7E | Initialize coprocessor, if present | 
| 80 | Disable onboard super I/O ports | 
| 81 | Late POST device initialization | 
| 82 | Detect & install external RS-232 ports | 
| 83 | Configure non-MDC IDE controllers | 
| 84 | Detect & install external parallel ports | 
| 85 | Initialize PnP ISA devices | 
| 86 | Reinitialize onboard I/O ports | 
| 87 | Configure motherboard configurable devices | 
| 88 | Initialize BIOS data area | 
| 89 | Enable NMI’s | 
| 8A | Initialize extended BIOS data area | 
| 8B | Test & initialize PS/2 mouse | 
| 8C | Initialize floppy controller | 
| 8F | Determine number of ATA drives | 
| 90 | Initialize hard disk controllers | 
| 91 | Initialize local BUS HD controllers | 
| 92 | Jump to user patch 2 | 
| 93 | Build MPTABLE for multiprocessor boards | 
| 94 | Disable A-20 line | 
| 95 | Install CD-ROM for boot | 
| 96 | Clear huge ES segment register | 
| 97 | Fix up multiprocessor table | 
| 98 | Search for options ROM’s | 
| 99 | Check for smart drive | 
| 9A | Shadow ROM option | 
| 9C | Set up power management | 
| 9E | Enable hardware interrupts | 
| 9F | Determine number of ATA & SCSI drives | 
| A0 | Set time of day | 
| A2 | Check key lock | 
| A4 | Initialize typematic rate | 
| A8 | Erase F2 prompt | 
| AA | Scan for F2 keystroke | 
| AC | Enter SETUP | 
| AE | Clear IN-POST flag | 
| B0 | Check for errors | 
| B2 | POST done, prepare for boot | 
| B4 | One short beep before boot | 
| B5 | Terminate quiet boot | 
| B6 | Check password (optional) | 
| B8 | Clear global descriptor table | 
| B9 | Clean up all graphics | 
| BA | Initialize DMI parameters | 
| BB | Initialize PnP option ROM’s | 
| BC | Clear parity checkers | 
| BD | Display multi boot menu | 
| BE | Clear screen optional | 
| BF | Check virus and backup reminders | 
| C0 | Try to boot with Int 19 | 
| C1 | Initialize POST error manager | 
| C2 | Initialize error logging | 
| C3 | Initialize error display function | 
| C4 | Initialize system error handler | 
| E0 | Initialize the chipset | 
| E1 | Initialize the bridge | 
| E2 | Initialize the processor | 
| E3 | Initialize system timer | 
| E4 | Initialize system I/O | 
| E5 | Check force recovery boot | 
| E6 | Checksum BIOS ROM | 
| E7 | Got to BIOS | 
| E8 | Set huge segment | 
| E9 | Initialize multiprocessor | 
| EA | Initialize OEM special code | 
| EB | Initialize PIC & DMA | 
| EC | Initialize memory type | 
| ED | Initialize memory type | 
| EE | Shadow boot block | 
| EF | System memory test | 
| F0 | Initialize interrupt vectors | 
| F1 | Initialize runtime clock | 
| F2 | Initialize video | 
| F3 | Initialize beeper | 
| F4 | Initialize BOOT | 
| F5 | Clear huge segment | 
| F6 | Boot to mini-DOS | 
| F7 | Boot to full DOS | 
Tabella Phoenix BIOS
| 02 | Verify real mode | 
| 03 | Disable non-maskable interrupt (NMI) | 
| 04 | Get CPU type | 
| 06 | Initialize system hardware | 
| 07 | Disable shadow and execute code from the ROM | 
| 08 | Initialize chipset with initial POST values | 
| 09 | Set IN POST flag | 
| 0A | Initialize CPU registers | 
| 0B | Enable CPU cache | 
| 0C | Initialize caches to initial POST values | 
| 0E | Initialize I/O component | 
| 0F | Initialize the local bus IDE | 
| 10 | initialize power management | 
| 11 | Load alternate registers with initial POST values | 
| 12 | Restore CPU control word during warm boot | 
| 13 | Initialize PCI bus mastering devices | 
| 14 | Initialize keyboard controller | 
| 16 | BIOS ROM checksum | 
| 17 | Initialize cache before memory autosize | 
| 18 | 8254 programmable interrupt timer initialization | 
| 1A | 8237 DMA controller initialization | 
| 1C | Reset programmable interrupt controller | 
| 20 | Test DRAM refresh | 
| 22 | Test 8742 keyboard controller | 
| 24 | Set ES segment register to 4GB | 
| 26 | Enable gate A20 line | 
| 28 | Autosize DRAM | 
| 29 | Initialize POST memory manager | 
| 2A | Clear 512KB base RAM | 
| 2C | RAM failure on address line xxxx | 
| 2E | RAM failure on data bits xxxx of low byte of memory bus | 
| 2F | Enable cache before system BIOS shadow | 
| 30 | RAM failure on data bits xxxx of high byte of memory bus | 
| 32 | Test CPU bus clock frequency | 
| 33 | Initialize Phoenix Dispatch Manager | 
| 36 | Warm start shut down | 
| 38 | Shadow system BIOS ROM | 
| 3A | Autosize cache | 
| 3C | Advanced configuration of chipset registers | 
| 3D | Load alternate registers with CMOS values | 
| 41 | Initialize extended memory for RomPilot | 
| 42 | Initialize interrupt vectors | 
| 45 | POST device initialization | 
| 46 | Check ROM copyright notice | 
| 47 | Initialize I20 support | 
| 48 | Check video configuration against CMOS | 
| 49 | Initialize PCI bus and devices | 
| 4A | Initialize all video adapters in system | 
| 4B | QuietBoot start (optional) | 
| 4C | Shadow video BIOS ROM | 
| 4E | Display BIOS copyright notice | 
| 4F | Initialize MultiBoot | 
| 50 | Display CPU type and speed | 
| 51 | Initialize EISA board | 
| 52 | Test keyboard | 
| 54 | Set key click if enabled | 
| 55 | Enable USB devices | 
| 58 | Test for unexpected interrupts | 
| 59 | Initialize POST display service | 
| 5A | Display prompt “Press F2 to enter SETUP” | 
| 5B | Disable CPU cache | 
| 5C | Test RAM between 512KB and 640KB | 
| 60 | Test extended memory | 
| 62 | Test extended memory address lines | 
| 64 | Jump to UserPatch1 | 
| 66 | Configure advanced cache registers | 
| 67 | Initialize Multi Processor APIC | 
| 68 | Enable external and CPU caches | 
| 69 | Setup system management mode (SMM) area | 
| 6A | Display external L2 cache size | 
| 6B | Load custom defaults (optional) | 
| 6C | Display shadow area message | 
| 6E | Display possible high address for UMB recovery | 
| 70 | Display error messages | 
| 72 | Check for configuration errors | 
| 76 | Check for keyboard errors | 
| 7C | Set up hardware interrupt vectors | 
| 7D | Initialize Intelligent System Monitoring | 
| 7E | Initialize coprocessor if present | 
| 80 | Disable onboard super I/O ports and IRQ’s | 
| 81 | Late POST device initialization | 
| 82 | Detect and install external RS232 ports | 
| 83 | Configure non-MCD IDE controllers | 
| 84 | Detect and install external parallel ports | 
| 85 | Initialize PC compatible PnP ISA devices | 
| 86 | Reinitialize onboard I/O ports | 
| 87 | Configure motherboard configurable devices (optional) | 
| 88 | Initialize BIOS data area | 
| 89 | Enable non-maskable interrupts (NMI’s) | 
| 8A | Initialize extended BIOS data area | 
| 8B | Test and initialize PS/2 mouse | 
| 8C | Initialize floppy controller | 
| 8F | Determine number of ATA drives (optional) | 
| 90 | Initialize hard disk controllers | 
| 91 | Initialize local bus hard disk controllers | 
| 92 | Jump to UserPatch2 | 
| 93 | Build MPTABLE for multi processor boards | 
| 95 | Install CD ROM for boot | 
| 96 | Clear huge ES segment register | 
| 97 | Fixup multi processor table | 
| 98 | Search for option ROM’s | 
| 99 | Check for SMART drive (optional) | 
| 9A | Shadow option ROM’s | 
| 9C | Set up power management | 
| 9D | Initialize security engine (optional) | 
| 9E | Enable hardware interrupts | 
| 9F | Determine number of ATA and SCSI drives | 
| A0 | Set time of day | 
| A2 | Check key lock | 
| A4 | Initialize typematic rate | 
| A8 | Erase F2 prompt | 
| AA | Scan for F2 key stroke | 
| AC | Enter setup | 
| AE | Clear boot flag | 
| B0 | Check for errors | 
| B1 | Inform RomPilot about the end of POST | 
| B2 | POST done – prepare to boot operating system | 
| B4 | One short beep | 
| B5 | Terminate QuietBoot (optional) | 
| B6 | Check password | 
| B7 | Initialize ACPI BIOS | 
| B9 | Prepare boot | 
| BA | Initialize DMI parameters | 
| BB | Initialize PnP option ROM’s | 
| BC | Clear parity checkers | 
| BD | Display multiboot menu | 
| BE | Clear screen | 
| BF | Check virus and backup reminders | 
| C0 | Try to boot with interrupt 19 | 
| C1 | Initialize POST Error Manager (PEM) | 
| C2 | Initialize error logging | 
| C3 | Initialize error display function | 
| C4 | Initialize system error handler | 
| C5 | PnP dual CMOS (optional) | 
| C6 | Initialize notebook docking (optional) | 
| C7 | Initialize notebook docking late | 
| C8 | Force check (optional) | 
| C9 | Extended checksum (optional) | 
| CA | Redirect Int 15h to enable remote keyboard | 
| CB | Redirect Int 13 to Memory Technologies Devices such as ROM, RAM, PCMCIA, and serial disk | 
| CC | Redirect Int 10h to enable remote serial video | 
| CD | Re-map I/O and memory for PCMCIA | 
| CE | Initialize digitizer and dispaly message | 
| D2 | Unknown interrupt | 
| The following are for boot block in Flash ROM | |
| E0 | Initialize the chipset | 
| E1 | Initialize the bridge | 
| E2 | Initialize the CPU | 
| E3 | Initialize the system timer | 
| E4 | Initialize system I/O | 
| E5 | Check force recovery boot | 
| E6 | Checksum BIOS ROM | 
| E7 | Go to BIOS | 
| E8 | Set Huge Segment | 
| E9 | Initialize Multi Processor | 
| EA | Initialize OEM special code | 
| EB | initialize PIC and DMA | 
| EC | Initialize Memory type | 
| ED | Initialize Memory size | 
| EE | Shadow Boot Block | 
| EF | System memory test | 
| F0 | Initialize interrupt vectors | 
| F1 | Initialize Run Time Clock | 
| F2 | Initialize video | 
| F3 | Initialize System Management Menager | 
| F4 | Output one beep | 
| F5 | Clear Huge Segement | 
| F6 | Boot to mini DOS | 
| F7 | Boot to Full DOS | 
 
						 
				