The modular debugger is an extensible, low-level debugger developed by Sun Microsystems

Sun Microsystems

Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...

 for the Solaris

Solaris

- Fiction :* Solaris , a 1961 science fiction novel by Stanisław Lem** Solaris , directed by B. Nirenburg** Solaris , directed by Andrei Tarkovsky** Solaris , directed by Steven Soderbergh...

 7 operating system. It is now open sourced, under the Common Development and Distribution License

Common Development and Distribution License

Common Development and Distribution License is a free software license, produced by Sun Microsystems, based on the Mozilla Public License , version 1.1....

 (CDDL).

Its source code is now available in all open source derivatives of Solaris, such as Illumos

Illumos

Illumos is a derivative of OS/Net , which basically is a Solaris/OpenSolaris kernel with the bulk of the drivers, core libraries, and basic utilities. It is dependent on OS/Net, which Illumos will follow very closely while allowing to retain changes to code which might be unacceptable to upstream...

.

History

The mdb project was started in 1997 by Mike Shapiro and others when the Solaris operating system was adding support for 64-bit architectures. Up until that point, Solaris was using the aging adb

ADB

ADB is a three-letter acronym that may refer to the intergovernmental organizations:* The Asian Development Bank, a non-profit financial institution whose aim is to help developing Asian countries...

 debugger developed by Steve Bourne (initially for the AT&T SVR4 Unix distribution).

It was very difficult to simply port adb from a 32-bit architecture to a 64-bit architecture, so Sun engineers decided to make a new debugger that would feature enhanced debugging capabilities, while being backward compatible with adb.