booting - how does it work?

[Loveless]

after post it will find the 1st hdd
check the mbr for primary partritions
go the the active primary paritrition and read the 1 block (boot sector)
boot sector will tell the bios where the system while are located.

is that how it goes?

[dos7]

The Following is a list of typical Basic Input/Output System (BIOS) commands in the order they're executed. This list illustrates the steps your system goes through from the moment it is powered on.


1. Initialize KBC (keyboard controller)
2. Enable RTC (real time clock)
3. Save CPU ID in CMOS
4. Initialize system timer
5. Verify boot block code
6. Disable DMA controllers
7. Issue KBC test
8. Start memory refresh
9. Determine memory (DRAM) size (density - 16mb,64mb,128mb,256mb and number of modules)
10. Validate main system BIOS
11. If the main system BIOS is found to be invalid, system beeps until floppy disk is inserted with the proper system BIOS
12. Once the main system BIOS is found to be valid, it is given control
13. For space reasons, the BIOS is compressed. the BIOS first decompresses the modules.
14. The BIOS then verifies that CMOS is valid
15. The BIOS the enables keyboard and PS/2 mouse.
16. Check for INS key press
17. Initialize CMOS if corrupt
18. Disable video (if soft reset)
19. Initialize chipset registers
20. Test 8254 timer
21. Initialize 8254 timer
22. Initialize ISRs
23. Initialize boot PCI devices (video and SCSI devices)
24. Display Sign on-message
25. Reset HDD controller
26. Check and display memory count.
27. Display "press DEL" message (to enter setup)
28. 8237 DMA controller test and initialization.
29. 8259 interrupt controller test.
30. Keyboard test, stuck key test, keyboard reset.
31. Initialize keystroke buffer.
32. Check to see if keyboard is locked.
33. Check for memory size mismatch.
34. Display soft errors and wait for F1 key.
35. Check for password
36. Set up LPT ports.
37. Set up serial ports
38. Initialize and reset the PS/2 mouse
39. Initialize floppy controller.
40. Initialize HDD controller and test for HDD.
41. Give control to SCSI ROM if present.
42. Set up system timer.
43. Math coprocessor initialization.
44. Update coprocessor in CMOS.
45. Check for extended keyboard.
46. Set keyboard ID
47. Program keyboard typematic rate.
48. Give control to E000 ROM if present (old network cards)
49. Display system configuration screen.
50. Initialize DMI (SMBIOS) information.
51. Issue Int 19 --- control to OS.


source: American Megatrends Inc.

[dos7]

sorry,,unfortunately,my reply does little to answer your question, oh well,, I was thinking of something else,I'm a scatter brain sometimes, but only when i am http://www.sysopt.com/forum/smile.gif

dos7

[Loveless]

thanks, that was very informative however iwas refering to "finding an OS -> booting that OS"