Questions tagged [dos-exe]
16 bits DOS MZ executable file format
24
questions
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vote
1
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Identifying C/C++ Library Functions
I am attempting to reverse-engineer an old DOS executable, which seems to have been compiled around 1992 using Microsoft's C compiler at the time.
When opening the executable in Ghidra no imports are ...
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4
votes
1
answer
262
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Ghidra 16-Bit DOS Strings
I am attempting to reverse-engineer a 16-Bit DOS MZ executable.
The file contains many different strings, most of which are printed out to the console at various points.
IDA seems to be able to pick ...
- 165
5
votes
1
answer
305
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Disassembling a DOS game with dynamic code/overlays in IDA Pro
I'm working on a disassembly of an old DOS game. (Real old: 16-bit, real mode.) The bulk of the game is in a large resource file of mixed binary and data; the executable basically just loads a chunk ...
2
votes
0
answers
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Need help with modifying DOS game extracting graphics codes
I have the following two Codes which make up a DOS Game Graphics Image Extracting Program, written in C# :-
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
...
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3
votes
0
answers
228
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Borland C++ 3.0 - Which code might produce this strangely convoluted ASM sequence?
I'm reverse-engineering a DOS binary that was compiled with Borland C++ 3.0, and I'm trying to create C code that will produce the same assembly as the original when compiled with the same compiler. ...
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0
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I have a dos file/database that i need to extract into MS Excel or My Sql
I have a dos file/database(decades old) that I need to extract into MS Excel or My SQL.
I am using a MacBook.
The file appears to have no extension.
The file type I can see when I do "get info&...
0
votes
0
answers
67
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How to maintain function ordering in an executable when replacing machine code with C step by step?
I am working on reversing a DOS game consisting of 16-bit MZ EXE files. I was able to determine the exectuables were generated by Microsoft C v 5.10, and loading the signatures from the static ...
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0
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Where to start analyzing a 16 bit dos program?
I've tried to analyze this small exe online.
I've tried with https://onlinedisassembler.com/odaweb/ (link) but it's hard for me to get the first question:
Why the tool doesn't try to detect the set ...
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0
votes
1
answer
190
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Within A Folder of 100s of 16-bit MS-DOS Disassembled EXEs Identify Ones That Need/Use DOS/4GW
So far I batch disassembled all files using following PowerShell and IDA:
$files = Get-Content S:\files.txt
ForEach ($file in $files)
{
Write-Host "Processing $file"
&"C:\Program Files\...
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10
votes
2
answers
841
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How did this 80286 detection code work?
I'm poking through a disassembled 16-bit DOS game circa 1992. The original system requirements state that the game needs an IBM AT-compatible machine or later, with the 286 processor, to run. And ...
- 258
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0
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IDA fixups, why and how
I'm using IDA 7 Freeware, not Pro. I've been using IDC to re-invent the wheel somewhat, but I'm learning a ton of stuff as I go along.
I have a 16-bit MSDOS exe which I'm reversing. I stripped out ...
- 11
1
vote
1
answer
477
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PE DOS stub content not commands
Does anyone know why the PE DOS stub often includes repetitive looking data that does not seem to be valid 16bit commands?
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3
votes
1
answer
885
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debugging a graphical msdos game
There is a DOS game I want to run through a debugger. I tried using (FreeDos)
DEBUG.COM over DosBox. But the problem is that this game uses graphics, and this messes up the output of DEBUG.COM.
Is ...
- 131
2
votes
0
answers
99
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COBOLII-MB 2.xx
I have a really old cobol program that was used to store some data, the company is no loger active and the program had to receive a key every 3 months. What tools I can use to reverse a cobol program? ...
- 133
3
votes
2
answers
7k
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Disassembling an MS-DOS EXE
I've been disassembling an MS-DOS EXE and I've been using this link http://www.delorie.com/djgpp/doc/exe/ to make heads and tails of the binary.
The header seems to be an older version compared to ...
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0
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2
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Issues rewriting portions of DOS app's assembly
I am working on editing an old DOS program's assembly, but I'm running into some odd issues.
I'm using IDA Pro 6.4 and a hex editor to patch. I'm code-caving the new data by removing old stuff never ...
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3
votes
2
answers
1k
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How to extract debug information from a DOS executable compiled with Watcom C/C++?
I have a DOS executable which has been compiled with Watcom C/C++ 10.0.
That EXE has debug symbols inside. I was wondering if there is any tool that allow to dump or extract that debug information (...
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2
votes
2
answers
6k
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How to quickly distinguish PE/DLL/DOS-MZ files based on magic numbers?
I know that the specifications of the Microsoft PE/DLL/DOS-MZ files states that the two first bytes of a PE/DLL/DOS-MZ file is MZ (0x4d,0x5a) orZM(0x5a,0x4d`).
The problem with such a small signature ...
- 18.8k
3
votes
1
answer
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16 bit Dos string concat function
I just got into reversing, i'm a bit puzzled by a part of the following code.
I know what its doing, from a technical aspect, but i don't really understand why its doing it.
This is the part I have a ...
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3
votes
3
answers
3k
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How to edit an .exe file without overwriting previous information
A qualifier - all I know of what I'm about to explain has been gathered from spending the last few hours researching to solve my problem, so forgive the naivety and clumsiness of a non-expert in this ...
- 162
2
votes
2
answers
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Is it possible to extract or otherwise edit the source code of an .exe file?
I have a small executable that I downloaded from the net, and that runs in the Command Line, which makes me think it may be a DOS program. The program works perfectly, but due to being developed by a ...
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4
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Any correlation between DOS Program Segment Prefix and the base address of loaded executable?
I'm using IDA to disassemble Test Drive III. It's a 1990 DOS game. The *.EXE has MZ format.
The game uses a number of anti-reversing features such as copying its code to segment (PSPseg+2be7) where ...
- 599
31
votes
9
answers
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Decompiling a 1990 DOS application
I have some crucial data written decades ago by an ancient 16bit DOS application. There are no docs, no source, and no information about the author. Just the 16 bit exe. I guess it's time for me to ...
- 599
12
votes
3
answers
9k
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Reverse engineer an old DOS QBasic executable
I recently decided to try my hand at reverse engineer an old DOS text based game that was coded in QBasic.
I found some info online about old DOS games disassembly but mostly for Wacom compiled C/C++ ...
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