The New Hacker's Dictionary

GC /G-C/

[from LISP terminology; 'Garbage Collect']

1. vt. To clean up and throw away useless things. "I think I'll GC the top of my desk today." When said of files, this is equivalent to GFR.

2. vt. To recycle, reclaim, or put to another use.

3. n. An instantiation of the garbage collector process.

'Garbage collection' is computer-science techspeak for a particular class of strategies for dynamically but transparently reallocating computer memory (i.e., without requiring explicit allocation and deallocation by higher-level software). One such strategy involves periodically scanning all the data in memory and determining what is no longer accessible; useless data items are then discarded so that the memory they occupy can be recycled and used for another purpose. Implementations of the LISP language usually use garbage collection.

In jargon, the full phrase is sometimes heard but the abbrev GC is more frequently used because it is shorter. Note that there is an ambiguity in usage that has to be resolved by context: "I'm going to garbage-collect my desk" usually means to clean out the drawers, but it could also mean to throw away or recycle the desk itself.

GCOS /jee'kohs/ n.

A quick-and-dirty clone of System/360 DOS that emerged from GE around 1970; originally called GECOS (the General Electric Comprehensive Operating System). Later kluged to support primitive timesharing and transaction processing. After the buyout of GE's computer division by Honeywell, the name was changed to General Comprehensive Operating System (GCOS). Other OS groups at Honeywell began referring to it as 'God's Chosen Operating System', allegedly in reaction to the GCOS crowd's uninformed and snotty attitude about the superiority of their product. All this might be of zero interest, except for two facts: (1) The GCOS people won the political war, and this led in the orphaning and eventual death of Honeywell Multics, and (2) GECOS/GCOS left one permanent mark on Unix. Some early Unix systems at Bell Labs used GCOS machines for print spooling and various other services; the field added to /etc/passwd to carry GCOS ID information was called the 'GECOS field' and survives today as the pw_gecos member used for the user's full name and other human-ID information. GCOS later played a major role in keeping Honeywell a dismal also-ran in the mainframe market, and was itself mostly ditched for Unix in the late 1980s when Honeywell began to retire its aging big iron designs.

GECOS /jee'kohs/ n.

See GCOS.