Source code is the sequence of logical statements and operations written in a human-readable computer programming language that controls the processing of data and the functionality of software.
The source code itself can be hundreds of thousands of lines of code and is normally designed and written by software programmers in programming languages such as C++, Java or Visual Basic.
When completed, the source code is compiled into "executable code" that can be downloaded, installed and run on a end user computer.
However, with only the executable code, end users have no ability to see how the software is processing data or performing functions and, for the most part, have no ability to change the operation of the software.
Because repairing problems or changing functionality is only possible with the source code, the escrow of source code is common in large software transactions involving custom developed or operationally critical applications.