app
/ap/ n. Short for `application program', as opposed to a systems program. What systems vendors are forever chasing developers to create for their environments so they can sell more boxes. Hackers tend not to think of the things they themselves run as apps; thus, in hacker parlance the term excludes compilers, program editors, games, and messaging systems, though a user would consider all those to be apps. Oppose {tool}, {operating system}.
arc
[primarily MSDOS] vt. To create a compressed {archive} from a group of files using SEA ARC, PKWare PKARC, or a compatible program. Rapidly becoming obsolete as the ARC compression method is falling into disuse, having been replaced by newer compression techniques. See {tar and feather}, {zip}.
arc wars
[primarily MSDOS] n. {holy wars} over which archiving program one should use. The first arc war was sparked when System Enhancement Associates (SEA) sued PKWare for copyright and trademark infringement on its ARC program. PKWare's PKARC outperformed ARC on both compression and speed while largely retaining compatibility (it introduced a new compression type that could be disabled for backward-compatibility). PKWare settled out of court to avoid enormous legal costs (both SEA and PKWare are small companies); as part of the settlement, the name of PKARC was changed to PKPAK. The public backlash against SEA for bringing suit helped to hasten the demise of ARC as a standard when PKWare and others introduced new, incompatible archivers with better compression algorithms.