The Interactive Disassembler, more commonly known as simply IDA, is a disassembler for computer software which generates assembly language source code from machine-executable code. It supports a variety of executable formats for different processors and operating systems. It also can be used as a debugger for Windows PE, Mac OS X, Mach-O, and Linux ELF executables. A decompiler plug-in for programs compiled with a C/C++ compiler is available at extra cost. The latest full version of Ida Pro is commercial software; an earlier and less capable version is available for download free of charge (version 5.0 as of November 2011).
IDA performs much automatic code analysis, using cross-references between code sections, knowledge of parameters of API calls, and other information. However, the nature of disassembly precludes total accuracy, and a great deal of human intervention is necessarily required; IDA has interactive functionality to aid in improving the disassembly. A typical IDA user will begin with an automatically generated disassembly listing and then convert sections from code to data and vice versa, rename, annotate, and otherwise add information to the listing, until it becomes clear what it does.
Created as a shareware application by Ilfak Guilfanov, IDA was later sold as a commercial product by DataRescue, a Belgian company, who improved it and sold it under the name IDA Pro. In 2007, Guilfanov founded Hex-Rays to pursue the development of the Hex-Rays Decompiler IDA extension. In January 2008, Hex-Rays assumed the development and support of DataRescue's IDA Pro.
Read more about Interactive Disassembler: Scripting, Supported Systems/processors/compilers