Big Gray Wall
n. What faces a {VMS} user searching for documentation. A full VMS kit comes on a pallet, the documentation taking up around 15 feet of shelf space before the addition of layered products such as compilers, databases, multivendor networking, and programming tools. Recent (since VMS version 5) DEC documentation comes with gray binders; under VMS version 4 the binders were orange (`big orange wall'), and under version 3 they were blue. See {VMS}. Often contracted to `Gray Wall'.
big iron
n. Large, expensive, ultra-fast computers. Used generally of {number-crunching} supercomputers such as Crays, but can include more conventional big commercial IBMish mainframes. Term of approval; compare {heavy metal}, oppose {dinosaur}.
Big Red Switch
[IBM] n. The power switch on a computer, esp. the `Emergency Pull' switch on an IBM {mainframe} or the power switch on an IBM PC where it really is large and red. "This !@%$% {bitty box} is hung again; time to hit the Big Red Switch." Sources at IBM report that, in tune with the company's passion for {TLA}s, this is often abbreviated as `BRS' (this has also become established on FidoNet and in the PC {clone} world). It is alleged that the emergency pull switch on an IBM 360/91 actually fired a non-conducting bolt into the main power feed; the BRSes on more recent machines physically drop a block into place so that they can't be pushed back in. People get fired for pulling them, especially inappropriately (see also {molly-guard}). Compare {power cycle}, {three-finger salute}, {120 reset}; see also {scram switch}.