steps of PST

[hullo911]

Hi, I am a student of computer science and would like to know the detailed steps of POST. Anyone who knows them of has a link to some relevant info, please reply..thank you

 

[I Saw OJ]

This is for a DOS boot, if booting into windows, steps 20 and bellow would be different. Let me know if i left anything out.

1. Reset pulse is set to CPU to clean internal registers
2. The PC register is incremented at OFFO
3. First instruction is executed at OFFFF
4. Instruction causes a jump to first line for postcode.
5. System interrupts are disabled and a 5-pattern read/write on all internal registers.
6. ROM BIOS performs a check sum
7. Upon check sum errors beep codes are generated.
8. Check to see if the boot was a warm or cold boot
9. 5-pattern read/write test is performed on first 16k of memory, upon passing remainder of postcode is transferred to first 16k of memory.
10. ROM BIOS scans devices to determine resources required
11. 5 pattern read/write is performed to verify the integrity of DMA register set
12. Initializes PIC and sets up a jump vector table
13. Clock output is checked frequency is verified to determine proper clock signal
14. 5 pattern read/write is performed to verify integrity of VRAM
15. Video card is initialized as well as, display.
16. 5 pattern read/write tests all memory past 16k
17. Remaining I/O devices are initialized
18. BIOS checks for expanded BIOS operations
19. Signal beep is produced, end of post
20. BIOS checks for MBR via interrupt 19h
21. OS loader is moved to memory for execution
22. OS loader check, locates initial system files
23. see the c: