Turbo-BASIC XL is an advanced version of the BASIC programming language for the Atari 8-bit family of home computers. It is a compatible superset of the Atari BASIC that shipped with the Atari 8-bit systems. Turbo-Basic XL was developed by Frank Ostrowski and published in the December 1985 issue of German computer magazine Happy Computer. A version for the 400/800 models was released shortly after as Frost Basic 1.4. Several modified versions working with different DOS systems have been released by other authors. Turbo-Basic XL greatly improves execution over Atari BASIC. An Atari BASIC program loaded into Turbo-BASIC, with no changes made, would generally run about three times as fast. A Turbo-Basic XL compiler created binary executables, further speeding up program performance to about ten times faster than Atari BASIC. Turbo-Basic XL also includes an expanded editor, support for named procedures, and similar block constructs, and added access to the underlying hardware, which, among other things, allowed operation of attached floppy drives without exiting to DOS. Ostrowski soon got a job with GFA Systemtechnik GmbH (at the time known as Integral Hydraulik) where he adapted Turbo-Basic XL into GFA BASIC for the Atari ST, which became one of the more popular BASICs on that platform. Background Since their release in 1979, the 8-bit family normally shipped with a version of Atari BASIC on a ROM cartridge, or built into the internal ROMs on later machines. This version of BASIC had a number of custom commands that allowed partial access to the system's advanced features like graphics and sound. It was notoriously slow, appearing at the very bottom of the list of microcomputer BASICs in the original version of David Ahl's Creative Computing benchmark. The poor performance of the official Atari BASIC led to a market for 3rd party BASIC interpreters with better performance or more commands. Among them was an official port of Microsoft BASIC sold by Atari, several improved versions released by Optimized Systems Software, who had written the original Atari BASIC under contract, and many others. There were also several Atari BASIC compilers from a variety of vendors. Turbo-Basic XL was a late entry to this list, first published in December 1985 as type-in program. It was unique in that it came in both interpreter and compiler versions. It included code to take advantage of the expanded memory available on the XL series machines, and later XE series.