Action! is a procedural programming language and integrated development environment written by Clinton Parker for the Atari 8-bit family. The language, which is similar to ALGOL, compiles to high-performance code for the MOS Technologies 6502 of the Atari computers. Action! was distributed on ROM cartridge by Optimized Systems Software starting in 1983. It was one of the company's first bank-switched 16 kB "Super Cartridges". Parker, working with Henry Baker, had previously developed Micro-SPL, a systems programming language for the Xerox Alto. Action! is largely a port of Micro-SPL concepts to the Atari with changes to support the 6502 processor and the addition of an integrated fullscreen editor and debugger. Action! was used to develop at least two commercial products—the HomePak productivity suite and Games Computers Play client program—and numerous programs in ANALOG Computing and Antic magazines. The editor inspired the PaperClip word processor. The language was not ported to other platforms. The assembly language source code for Action! was made available under the GNU General Public License by the author in 2015. History Micro-SPL While taking his postgraduate studies, Parker started working part-time at Xerox PARC working on printer drivers. He later moved to the Xerox Alto project where he wrote several games for the system. His PhD was in natural language parsing and he had worked on compiler theory during his graduate work. Henry Baker and Parker released Micro-SPL in September 1979. Micro-SPL was intended to be used as a systems programming language on the Xerox Alto workstation computer, which was normally programmed in BCPL. The Alto used a microcode system which the BCPL compiler output. Micro-SPL output the same format, allowing BCPL programs to call Micro-SPL programs. Aside from differences in syntax, the main difference between Micro-SPL and BCPL, and the reason for its existence, was that Micro-SPL produced code that was many times faster than the native BCPL compiler. In general, Micro-SPL programs were expected to run about ten times as fast as BCPL, and about half as fast as good hand-written microcode. In comparison to microcode, they claimed it would take half as long to write and 10% of the time to debug it. Action! It was during this period that Parker purchased an Atari for use at home, and was disappointed with the lack of development systems for this platform. This was the impetus for the development of Action! Parker initially considered releasing the system