A BASIC compiler (and IDE) which was originally created by Robert Zale and ran under DOS. It was originally distributed by Borland under the name Turbo Basic, however Mr Zale decided to distribute it on his own. It is currently distributed by PowerBASIC, Inc.
The DOS version provided many innovative features in the time of its popularity, including virtual arrays (arrays which were stored in expanded memory and automatically loaded back into DOS memory as required by the compiler), many different data types, easy TSR creation and code pointers.
Although the DOS version is still available, the current Windows version is the up-to-date release. It is marketed as a competitor to Visual Basic, being both faster and more lightweight, and it includes inline assembly support.
Many add-ons are available, some of the more popular ones including PowerTree (a B+Tree toolkit), DOSBox (tools to integrate DOS programs into a Windows environment) and SQL Tools, a library to allow access to databases.