Turbo Pascal is a software development system that includes a compiler and an integrated development environment (IDE) for the Pascal programming language running on CP/M, CP/M-86, and MS-DOS, developed by Borland under Philippe Kahn's leadership. For versions 6 and 7 (last), both a lower-priced Turbo Pascal and more expensive Borland Pascal were produced; Borland Pascal was more oriented towards professional software development, with more libraries and standard library source code. The name Borland Pascal is also used more generically for Borland's dialect of the Pascal programming language, significantly different from Standard Pascal. Borland has released three old versions of Turbo Pascal free of charge because of their historical interest: the original Turbo Pascal (now known as 1.0), and versions 3.02 and 5.5 for DOS.