Modular Debugger (MDB)

About MDB

If you were a detective and were investigating at the scene of a crime, you
might interview the witnesses and ask them to describe what happened and who
they saw. However, if there were no witnesses or these descriptions proved
insufficient, you might consider collecting fingerprints and forensic evidence
that could be examined for DNA to help solve the case. Often, software program
failures divide into analogous categories: problems that can be solved with
source-level debugging tools, and problems that require low-level debugging
facilities, examination of core files, and knowledge of assembly language to
diagnose and correct. MDB is a debugger designed to facilitate analysis of this
second class of problems.

It might not be necessary to use MDB in every case, just as a detective doesn't
need a microscope and DNA evidence to solve every crime. However, when
programming a complex low-level software system such as an operating system,
these situations can occur frequently. As a result, MDB is designed as a
debugging framework that allows you to construct your own custom analysis tools
to aid in the diagnosis of these problems. MDB also provides a powerful set of
built-in commands that allow you to analyze the state of your program at the
assembly language level.

Using MDB

MDB is available on Solaris systems as two commands that share common features:
mdb and kmdb. You can use the mdb command interactively or in scripts to debug
live user processes, user process core files, kernel crash dumps, the live
operating system, object files, and other files. You can use the kmdb command to
debug the live operating system kernel and device drivers when you also need to
control and halt the execution of the kernel. To start mdb, execute the mdb(1)
command. To start kmdb, boot the system as described in the kmdb(1) man page, or
execute the mdb command with the -K option.

MDB Documentation

MDB is described in detail in the
Solaris Modular Debugger Guide, and
also in the
mdb(1)
and
kmdb(1) manual pages. MDB is available on Solaris 8,
Solaris 9, and Solaris 10, and kmdb is only available in Solaris 10.

For more information on the internal MDB architecture and where to find
associated source code, refer to the Architecture section.  Also
check out the Tips and Tricks section, which covers a wide variety of
useful topics outside the standard documentation.  If you're interested in MDB devlopment, you should search for "mdb" in the  bug database for an interesting starter bug.  Or check out the Future Projects section for possible long-term enhancements.

MDB Discussion

If you want to discuss MDB features and bugs, learn more about how to use MDB,
or share an interesting tale of a problem you debugged, join the MDB
Forum.