China DOS Union

Sender: jan1 (Spirit), Forum: DOS
Subject: Re: Analysis of MS-DOS Boot Loader
Posted: BBS Tsinghua BBS Station (Thu Sep 11 19:48:24 1997)

【In reply to cq (Seven Virtues Layman)】
: Which expert can post it by the way, thanks a lot. I haven't found the explanation in the books I've read.

The following is a partition structure of a hard disk, divided into one pri and one ext, and the ext contains one logical
C:\>debug -a100 1876:0100 mov ax,201 1876:0103 mov bx,7c00 1876:0106 mov cx,1 ; col 0, sector 1 1876:0109 mov dx,81 ; Second hard disk, head 0 1876:010C int 13 1876:010E int 3 1876:010F -g=100 AX=0050 BX=7C00 CX=0001 DX=0081 SP=FFEE BP=0000 SI=0000 DI=0000 DS=1876 ES=1876 SS=1876 CS=1876 IP=010E NV UP EI PL NZ NA PO NC 1876:010E CC INT 3 -d7d80 1876:7D80 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 1876:7D90 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 1876:7DA0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 1876:7DB0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 01 ................ ^^ dh for pri-partition 1876:7DC0 01 00 06 3F 60 F3 20 00-00 00 E0 9F 0F 00 00 00 ...?`. ......... ^^^^^cx for pri-partition ^^ dh for ext-partition 1876:7DD0 41 F4 05 3F E0 F1 00 A0-0F 00 00 F0 0F 00 00 00 A..?............ ^^^^^cx for ext-partition 1876:7DE0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 1876:7DF0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 55 AA ..............U. -a106 1876:0106 mov cx,f441 ; 1876:0109 -g=100 ; reading col:sec f441, head 0, this is ext-partition AX=0050 BX=7C00 CX=F441 DX=0081 SP=FFEE BP=0000 SI=0000 DI=0000 DS=1876 ES=1876 SS=1876 CS=1876 IP=010E NV UP EI PL NZ NA PO NC 1876:010E CC INT 3 -d7d80 1876:7D80 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 1876:7D90 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 1876:7DA0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 1876:7DB0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 01 ................ ^^ dh for logical driver 1876:7DC0 41 F4 06 3F E0 F1 20 00-00 00 E0 EF 0F 00 00 00 A..?.. ......... ^^^^^cx for logical driver 1876:7DD0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 1876:7DE0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 1876:7DF0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 55 AA ..............U.

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※ Source:·BBS Tsinghua BBS Station bbs.net.tsinghua.edu.cn·

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I don't understand it, but it sounds impressive

Great expert! I bow down and submit

Where are the results?

Pure DOS and XP system coexist, don't know how to install to enter the dual - system boot interface

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