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Posted: **Sat Jul 15, 2006 11:54 pm**

hello, when i disassemble the windows 2000 and 2003 mbr, i found if the 63 secoter symbol not is 55AA, it will show " Error loading operating system", but it should show "Missing Operating system". it can be easily fit, but they do nothing.

Posted: **Sun Jul 16, 2006 4:46 am**

I don't know what you mean.. I have looked at my Windows 2000 boot sector many times and the 55AA is present. In fact, here is the whole hex code of it:

Code: Select all

EB 52 90 4E 54 46 53 20 20 20 20 0 2 8 0 0 0 0 0 0 0 F8 0 0 3F 0 F0 0 3F 0 0 0 0 0 0 0 80 0 80 0 80 46 80 0 0 0 0 0 4 0 0 0 0 0 0 0 68 4 8 0 0 0 0 0 F6 0 0 0 1 0 0 0 2F 94 5D B0 98 5D B0 C2 0 0 0 0 FA 33 C0 8E D0 BC 0 7C FB B8 C0 7 8E D8 E8 16 0 B8 0 D 8E C0 33 DB C6 6 E 0 10 E8 53 0 68 0 D 68 6A 2 CB 8A 16 24 0 B4 8 CD 13 73 5 B9 FF FF 8A F1 66 F B6 C6 40 66 F B6 D1 80 E2 3F F7 E2 86 CD C0 ED 6 41 66 F B7 C9 66 F7 E1 66 A3 20 0 C3 B4 41 BB AA 55 8A 16 24 0 CD 13 72 F 81 FB 55 AA 75 9 F6 C1 1 74 4 FE 6 14 0 C3 66 60 1E 6 66 A1 10 0 66 3 6 1C 0 66 3B 6 20 0 F 82 3A 0 1E 66 6A 0 66 50 6 53 66 68 10 0 1 0 80 3E 14 0 0 F 85 C 0 E8 B3 FF 80 3E 14 0 0 F 84 61 0 B4 42 8A 16 24 0 16 1F 8B F4 CD 13 66 58 5B 7 66 58 66 58 1F EB 2D 66 33 D2 66 F B7 E 18 0 66 F7 F1 FE C2 8A CA 66 8B D0 66 C1 EA 10 F7 36 1A 0 86 D6 8A 16 24 0 8A E8 C0 E4 6 A CC B8 1 2 CD 13 F 82 19 0 8C C0 5 20 0 8E C0 66 FF 6 10 0 FF E E 0 F 85 6F FF 7 1F 66 61 C3 A0 F8 1 E8 9 0 A0 FB 1 E8 3 0 FB EB FE B4 1 8B F0 AC 3C 0 74 9 B4 E BB 7 0 CD 10 EB F2 C3 D A 41 20 64 69 73 6B 20 72 65 61 64 20 65 72 72 6F 72 20 6F 63 63 75 72 72 65 64 0 D A 4E 54 4C 44 52 20 69 73 20 6D 69 73 73 69 6E 67 0 D A 4E 54 4C 44 52 20 69 73 20 63 6F 6D 70 72 65 73 73 65 64 0 D A 50 72 65 73 73 20 43 74 72 6C 2B 41 6C 74 2B 44 65 6C 20 74 6F 20 72 65 73 74 61 72 74 D A 0 0 0 0 0 0 0 0 0 0 0 0 0 0 83 A0 B3 C9 0 0 55 AA

As you can see 55 AA is present. Unless I misunderstood you, you either have a bad hd or a bad program that looks at your hard drive sectors.

Posted: **Sun Jul 16, 2006 7:23 am**

my boot sector's symbol is 55aa too, i mean's if you change the 55aa symbol to another symbol.

Posted: **Sun Jul 16, 2006 8:27 am**

Strange.. perhaps your BIOS just gives a different message than a normal BIOS? I don't think it's doing that because it recognizes it's a Windows MBR.

Posted: **Sun Jul 16, 2006 5:41 pm**

i think you don't know how the windows MBR work, it will read the 63 sector and check if last two string is "55aa", if it is, it will gose will. but if it isn't "55aa", it will show a error message. the message should be "Missing operating system". the bug is it will show "Error loading operating system".

Posted: **Sun Jul 16, 2006 6:50 pm**

Are you trying to say that the Win2000/2003 MBR displays this message?

The BIOS looks at the first sector, and if it has the signature "55 AA" at the end, loads it and executes it.

Perhaps what you're seeing is MS's error message if it is unable to load Windows?

Posted: **Sun Jul 16, 2006 9:41 pm**

nirvana111 wrote:hello, when i disassemble the windows 2000 and 2003 mbr, i found if the 63 secoter symbol not is 55AA, it will show " Error loading operating system", but it should show "Missing Operating system". it can be easily fit, but they do nothing.

I'm confused. Why is "Missing Operating System" a more appropriate error than "Error loading operating system" when the partition does not contain a valid boot sector? Other then both of the messages being vague and not terribly helpful, I don't see why one is wrong but the other is right.

Posted: **Mon Jul 17, 2006 1:17 am**

I'm confused. Why is "Missing Operating System" a more appropriate error than "Error loading operating system" when the partition does not contain a valid boot sector? Other then both of the messages being vague and not terribly helpful, I don't see why one is wrong but the other is right.

if you be familiar with the 2000/2003 MBR, you will know the difference between the two message. if read sector error, it will show "Error loading operating system" , and if read sector is will but isn't a boot sector it will show "Missing Operating System".

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i found a bug in microsoft win2000 and win2003 mbr

i found a bug in microsoft win2000 and win2003 mbr

Re: i found a bug in microsoft win2000 and win2003 mbr