operating system, jargon
A piece of code or a coding technique that depends on the protected multitasking environment with relatively low process-spawn overhead that exists on virtual-memory Unix systems.
Common Unixisms include: gratuitous use of "fork"; the assumption that certain undocumented but well-known features of Unix libraries such as "stdio" are supported elsewhere; reliance on obscure side-effects of system calls (use of "sleep" with a 0 argument to tell the scheduler that you're willing to give up your time-slice, for example); the assumption that freshly allocated memory is zeroed; and the assumption that fragmentation problems won't arise from never freeing memory.
Compare vaxocentrism. See also New Jersey.