Editing Turbo-BASIC XL (section)

==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 [[read only memory|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]].<ref>{{cite magazine |url=https://archive.org/stream/creativecomputing-1983-11/Creative_Computing_v09_n11_1983_November#page/n271/mode/2up |title= Benchmark comparison test |magazine=Creative Computing |date=November 1983 |page=260 |first=David |last=Ahl}}</ref>

The poor performance of the official Atari BASIC led to a market for 3rd party [[BASIC interpreter]]s 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. This meant that it could not run on the original 400/800 systems, which led Ostrowski to make a port known as Frost BASIC (short for "Frank Ostrowski") that was tied to [[Atari DOS]] 2.0.

The internal disk-related commands were tied to particular versions of DOS.  A number of ports to different versions of DOS became available.