Reverse Engineering Stack Exchange
Reverse Engineering Stack Exchange

Questions tagged [dos]

Disc Operating System, started as 16-bit OS for PC-AT/XT x86++ platforms

Operating system for PC-AT/XT x86++

  • mostly known was MS-DOS from Microsoft but also other clones surface's
  • manages first 1MB of memory (20bit segmentated addressing from i8086/8088++)
  • 640KB for programs
  • rest for system, drivers
  • memory above 640KB was accessible only by drivers
  • himem.sys - access to 640-1024 KB
  • emm386.sys or qemm386.sys - access to 1-64 MB (XMS memory)
  • support for 2 FDD FAT11
  • HDD with FAT16 support
  • natively it uses text video modes on CGA/EGA/VGA 80x25 characters
  • support these file extensions
  • *.sys - driver
  • *.com - executable fitted inside single 64KB segment
  • *.exe - executable with more segments
48 questions
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Reverse Engineering (very) old DOS calculation program

I have recently joined a company that is specialized in air ducts & ventilation systems and I was quite surprised when I noticed that they are still using a DOS program to calculate the pressure loss of a specific duct system. You see, when air…
user28805
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Trying to view sprites from an old game

I am looking to decompile the sprite data from an old DOS Game (Treasure Cove). If it helps any, I found that the game was written with the Borland C++ Programming Language. It appears that the sprites are located in TLD files, though I am incapable…
SonAmyFan362
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BasicCompiler: wanted binaries which BC.exe or QB.exe (compiler) generates

I was in charge of analyze and reverse engineering the old unknown EXE for past few month. The binary works on MS-DOS for NEC-PC98 (retro PC), old (20years more ago), nobody knows how it's made. I done the job and knew the binary had been generated…
roentgen
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Change a text in DOS executables

We have a DOS executable program like to NC. How do we find and change a text or a ASCII art in it? I'm a newbie in reverse.
ali
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debugger d32 from dos4g package

I have 32 bit MS-DOS app, run with dos4g.exe. I have package of dos4g and found d32.exe debugger in it. I run debugger with my app using bat file: d32.exe myapp.exe But after start d32.exe it stops not on main() of myapp.exe. d32.exe stops on code…
black4
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Converting 2 bytes into date

I am trying to convert the following bytes into their corresponding dates. I am not 100% on format the dates is stored, this format is returned from the application that read them. Bytes Date value 25 47 = 04/19/2005 32 47 = 05/02/2005 30 47 =…
Jackson
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