Debug, CDBA and debxxf

A. Debug

Debug is an extended MS Debug clone. There are two binaries available: the small and simple DEBUG.COM, which can debug DOS 16-bit real-mode applications only and DEBUGX.COM, which additionally can debug protected-mode DPMI applications, both 16-bit and 32-bit.

Read Debug's Readme.txt (includes a history/changelog). Also included is a DEBUG tutorial.
 
Some screenshots of a DEBUG session
 
Debug v1.18 05/18/2009 binary + source

List of all versions available for download

 

B. CDBA

CDBA is a CDB-like debugger - with a commandline UI - written in assembly (Masm-style). This debugger uses the MS Debug Engine. It can debug Win32 applications and DOS applications running in NTVDM, and allows debugging on both assembly and source code level. CDBA is Public Domain.
 
CDBA v0.78 10/25/2009 binary + source

 

C. debxxf

debxxf is the name of a DPMI debugger for DOS and Win16 applications. It has more features than the simple DEBUG, but OTOH it won't run with simple DPMI hosts like cwsdpmi and it needs more memory.

There are 3 incarnations of debxxf:
  • deb32f - debugger for 32-bit DPMI clients (DOS).
  • deb16f - debugger for 16-bit DPMI clients (DOS).
  • deb16fw - debugger for 16-bit DPMI clients (Windows).
The DOS versions of the debugger have the following features:
  • may debug real mode and protected mode apps
  • may debug apps with mixed 16/32 bit code segments
  • may debug mode switches in both directions
  • may debug apps using VGA/VESA graphics locally
  • may debug DOS kernel and ROM code
  • is not restricted to a specific file format. Any DOS/DPMI application can be debugged.
  • supports remote debugging and a second video adapter
  • is able to display various DOS/DPMI/CPU status information
There are also some things which you might not regard as a feature::
  • the debugger has a simple, line-oriented user interface (DOS DEBUG alike)
  • there is no support for debugging on source code level
  • the debugger runs as a DPMI client, it is not suitable to debug system-level code or applications running as a VCPI client.
  • the debugger requires a DPMI host with integrated DOS extender. It won't run on native DPMI hosts like CWSDPMI.
Read debxxf's changelog.
 
Some screenshots of a debxxf session
 
v2.9.6 01/11/2008 debxxf (DOS) deb16fw (Win16)
v2.9.5 12/06/2007 debxxf (DOS) deb16fw (Win16)