Solaris Modular Debugger Guide

Chapter 1 Modular Debugger Overview

The Modular Debugger (MDB) is a general purpose debugging tool for Solaris whose primary feature is its extensibility. This book describes how to use MDB to debug complex software systems, with a particular emphasis on the facilities available for debugging the Solaris kernel and associated device drivers and modules. The book also includes a complete reference for and discussion of the MDB language syntax, debugger features, and MDB Module Programming API.


Debugging is the process of analyzing the execution and state of a software program in order to remove defects. Traditional debugging tools provide facilities for execution control so that programmers can re-execute programs in a controlled environment and display the current state of program data or evaluate expressions in the source language used to develop the program. Unfortunately, these techniques are often inappropriate for debugging complex software systems such as:

MDB is a tool that provides a completely customizable environment for debugging these programs and scenarios, including a dynamic module facility that programmers can use to implement their own debugging commands to perform program-specific analysis. Each MDB module can be used to examine the program in several different contexts, including live and post-mortem. The Solaris Operating Environment includes a set of MDB modules designed to aid programmers in debugging the Solaris kernel and related device drivers and kernel modules. Third-party developers might find it useful to develop and deliver their own debugging modules for supervisor or user software.

MDB Features

MDB provides an extensive collection of features for analyzing the Solaris kernel and other target programs. You can:

Future Enhancements

MDB provides a stable foundation for developing advanced post-mortem analysis tools. In the future, the Solaris operating environment will include additional MDB modules that provide even more sophisticated functionality for debugging the kernel and other software programs. You can use MDB to debug existing software programs, and develop your own modules to improve your ability to debug your own Solaris drivers and applications.