Sponsoring website: Emergency Boot C uide to DEBUG The Microsoft® Windows. EXE DOS Stub Program Copyright©2004,2013 by Daniel B. Sedory This page may be freely copied for PERSONAL use ONLY! ( It may NOT be used for ANY other purpose unless you havefirst contacted and received permission from the author! ) In the early days of Microsoft® Windows, The Windows1.x, 2.x and 3.xx OS not only existed in the same volumes as Microsoft® DOS, but also ran on top of an MS- DOS OS. It was not only possible, but very probable that a user might attempt to run some of the Windows® programs under DOS. Therefore, Microsoft® programmers made sure all Windows® programs would have a simple 16-bit DOS program placed at the front of each Windows executable that would alert the user if they were attempting to run a Windows® program under DOS. This is all the DOS Stub program does. All the Details of the DOS Stub Program One of the simplest. EXE programs you can run under DEBUG is the so-called DOS Stub found inside hundreds of Windows® executables. The Stub program itself has not changed in many years, and we'll examine it in detail in a Step-by- Step DEBUG session below. There are some. If you open a copy of NOTEPAD. EXE inside a Hex editor (such as Hx D it will appear similar to this: ( The beginning of NOTEPAD. EXE from Windows XP Pro SP-3; April 14, 2008, AM, 69,120 bytes.) Figure 1. Note the first two bytes, 4d 5a or their ASCII equivalent: MZ. Whenever the DOS EXEC function is called to examine a file (anytime you load an. EXE or. COM program into DEBUG 2.0+ for example) and it finds MZ as the first two bytes, that file will always be considered an. EXE executable! So, what happens if you enter: debug notepad.exe at the prompt in a DOS-box? Well, the first bytes you'll see when you do a dump command are: You may ask: Hey, I thought DEBUG always loaded files from the.
DOS stubsby X- Calibre (of Diamond) Essay Level: Intermediate Date: 4-6-'99 Tools used: ASM compiler including executable programs and 2) Saving the file with only the changes that you make; unlike many old Text Editors which always add a couple extra bytes at the end of each file* ( See note below). Also, most Text Editors will drastically change or even truncate binary files (chop off a large portion at the end of the copied file when loading it into the editor so you should never use a Text Editor to make changes to a file unless you know for sure it's a plain text type file! Note: You should always make a copy of any file you need to open with a Hex Editor. Unlike text files, changing a single byte in a program or binary data file (such as a Word. DOC file especially by accident, may make it impossible to ever run or use the file again! Although I'm trying to comment on a number of helpful 'free' Hex editors here, the first one on the list ( FRHED) is, in my opinion, the best everyday workhorse; a program for searching through and making changes to dozens of files per session on a daily basis. Take this link for a full Review of: FRHED - FRee Hex EDitor Hx D by Maël Hörz. Maël's Home Page. New: Tutorial using Hx D Hx D is a proven Hex Editor not only for editing any binary files on your system but also for editing your hard disk drive sectors from within Windows™ 2000/ XP! This made it the first FREE Disk Editor that can do many of things people purchase the commercial editor Win Hex for! Hx D is still being developed, and its author continues to be.
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