himself, but later decided to partner with Optimized Systems Software (OSS) for sales and distribution. OSS focused on utilities and programming languages like BASIC XL, so this was a natural fit for Action! Sales were strong enough for Parker to make a living off the royalties for several years. The IBM PC had C compilers available, and Parker decided there was no point in porting Action! to that platform. As the sales of the Atari 8-bit platforms wound down, in North America at least, OSS wound down as well. Late in its history Action! distribution moved from OSS to Electronic Arts, but they did little with the language and sales ended shortly after. In a 2015 interview, Parker expressed his surprise in the level of support the language continued to receive, suggesting there appeared to be more interest in it then than there had been in the late 1980s. Development environment Action! was one of the earlier examples of the OSS SuperCartridge format. ROM cartridges on the Atari were normally limited to 8 kB, which limited its ability to support larger programs. The SuperCartridge had 16 kB organized as four 4 kB blocks, two of which were visible at any time. The lower 4 kB did not change, and system could bank switch between the other three blocks by changing the value in address $AFFF. Action! used this design by breaking the system into four sections, the editor, the compiler, a monitor for testing code and switching between the editor and compiler, and the run-time library. The run-time library is stored in the cartridge itself. To distribute standalone applications requires a separate run-time package which was sold by OSS as the Action! Toolkit. Action! constructs were designed to map cleanly to 6502 opcodes, to provide high performance without needing complex optimizations in the one-pass compiler. For example, local variables are assigned fixed addresses in memory, instead of being allocated on the stack of activation records. This eliminates the significant overhead associated with stack management, which is especially difficult in the case of the 6502's 256-byte stack. However, this precludes the use of recursion. Unlike the integrated Atari BASIC and Atari Assembler Editor environments, the Action! editor does not use line numbers. It features a full-screen, scrolling display capable of displaying two windows, as well as block operations and global search and replace. The monitor serves as a debugger, allowing an