| Appendix A: BIOS POST Checkpoint Codes |
|
|
Checkpoint | Code Description |
24h | The configuration required before interrupt vector initialization |
| has completed. Interrupt vector initialization is about to begin. |
25h | Interrupt vector initialization is done. Clearing the password if the |
| POST DIAG switch is on. |
27h | Any initialization before setting video mode will be done next. |
28h | Initialization before setting the video mode is complete. Configuring |
| the monochrome mode and color mode settings next. |
2Ah | Bus initialization system, static, output devices will be done next, if |
| present. See the last page for additional information. |
2Eh | Completed |
| controller is not found, performing the display memory read/write |
| test next. |
2Fh | The EGA/VGA controller was not found. The display memory read/ |
| write test is about to begin. |
30h | The display memory read/write test passed. Look for retrace |
| checking next. |
31h | The display memory read/write test or retrace checking failed. |
| Performing the alternate display memory read/write test next. |
32h | The alternate display memory read/write test passed. Looking for |
| alternate display retrace checking next. |
34h | Video display checking is over. Setting the display mode next. |
37h | The display mode is set. Displaying the power on message next. |
38h | Initializing the bus input, IPL, general devices next, if present. See the |
| last page of this chapter for additional information. |
39h | Displaying bus initialization error messages. See the last page of this |
| chapter for additional information. |
3Ah | The new cursor position has been read and saved. Displaying the |
| Hit <DEL> message next. |
3Bh | The Hit <DEL> message is displayed. The protected mode memory |
| test is about to start. |
40h | Preparing the descriptor tables next. |
42h | The descriptor tables are prepared. Entering protected mode for the |
| memory test next. |
43h | Entered protected mode. Enabling interrupts for diagnostics mode |
| next. |
44h | Interrupts enabled if the diagnostics switch is on. Initializing data to |
| check memory wraparound at 0:0 next. |
45h | Data initialized. Checking for memory wraparound at 0:0 and finding |
| the total system memory size next. |
46h | The memory wraparound test is done. Memory size calculation has |
| been done. Writing patterns to test memory next. |
