Share and enjoy!

1. Commonly found at the end of software release announcements and README files, this phrase indicates allegiance to the hacker ethic of free information sharing (see hacker ethic).

2. The motto of the Sirius Cybernetics Corporation (the ultimate gaggle of incompetent suits) in Douglas Adams's "Hitch Hiker's Guide to the Galaxy". The irony of using this as a cultural recognition signal appeals to freeware hackers.

[Jargon File]

shared memory

1. Memory in a parallel computer, usually RAM, which can be accessed by more than one processor, usually via a shared bus or network.

It usually takes longer for a processor to access shared memory than to access its own private memory because of contention for the processor-to-memory connections and because of other overheads associated with ensuring synchronised access. Computers using shared memory usually have some kind of local cache on each processor to reduce the number of accesses to shared memory. This requires a cache consistency protocol to ensure that one processor's cached copy of a shared memory location is invalidated when another processor writes to that location.

The alternative to shared memory is message passing where all memory is private to some particular processor and processors communicate by sending messages down special links. This is usually slower than shared memory but it avoids the problems of contention for memory and can be implemented more cheaply.

2. Memory which can be access by more than one process in a multitasking operating system with memory protection. Some Unix variants, e.g. SunOS provide this kind of shared memory.

Unix manual pages: shmop(2), shmctl(2), shmget(2).

Last updated: 1994-10-20

Shared Time Repair of Big Electronic Systems


(STROBES) A language for computer testing.

[Sammet 1969, p. 699].

Last updated: 1995-02-06



/sheir'weir/ Software that, like freeware, can be usually obtained (downloaded) and redistributed for free, but most often is under copyright and does legally require a payment in the EULA, at least beyond the evaluation period or for commercial applications. This payment, as well as fulfilling the user's legal obligations, may buy additional support, documentation, or functionality. Generally, source code for shareware programs is not available. Shareware is sometimes also nagware and/or crippleware, which muddles the term and is frowned upon in the community.

See also careware, charityware, guiltware, postcardware, and -ware; compare payware.

[Jargon File]

Last updated: 2002-01-30

Nearby terms:

shardingShare and enjoy!shared memoryShared Time Repair of Big Electronic Systems

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