WhatIs

/hə-ˈlō wȯl/

excl. See wall.

/hə-ˈlō sā-lər/

interj. Occasional West Coast equivalent of hello, world; seems to have originated at SAIL, later associated with the game Zork (which also included "hello, aviator" and "hello, implementor"). Originally from the traditional hooker's greeting to a swabbie fresh off the boat, of course.

/he-lən ke-lər mōd/

n. State of a hardware or software system that is deaf, dumb, and blind, i.e., accepting no input and generating no output, usually due to an infinite loop or some other excursion into {deep space}. (Unfair to the real Helen Keller, whose success at learning speech was triumphant.)

See also go flatline, catatonic.

/hi:'zen-buhg/

[from Heisenberg's Uncertainty Principle in quantum physics]

n. A bug that disappears or alters its behavior when one attempts to probe or isolate it. Antonym of Bohr bug; see also mandelbug. In C, nine out of ten heisenbugs result from either fandango on core phenomena (esp. lossage related to corruption of the malloc arena) or errors that smash the stack.

/he-vē-wāt/

adj. High-overhead; baroque; code-intensive; featureful, but costly. Esp. used of communication protocols, language designs, and any sort of implementation in which maximum generality and/or ease of implementation has been pushed at the expense of mundane considerations such as speed, memory utilization, and startup time. EMACS is a heavyweight editor; X is an *extremely* heavyweight window system.

/he-vē wi-zər-drē/

n. Code or designs that trade on a particularly intimate knowledge or experience of a particular operating system or language or complex application interface. Distinguished from deep magic, which trades more on arcane *theoretical* knowledge. Writing device drivers is heavy wizardry; so is interfacing to X (sense 2) without a toolkit. Esp. found in comments similar to "Heavy wizardry begins here...".

Compare voodoo programming.

/he-vē me-tᵊl/

[Cambridge]

n. Syn. big iron.

/härt-ˌbēt/

n. 1. The signal emitted by a Level 2 Ethernet transceiver at the end of every packet to show that the collision-detection circuit is still connected.

2. A periodic synchronization signal used by software or hardware, such as a bus clock or a periodic interrupt.

3. The natural oscillation frequency of a computer's clock crystal, before frequency division down to the machine's clock rate.

/heds dau̇n/

[Sun]

adj. Concentrating, usually so heavily and for so long that everything outside the focus area is missed.

See also hack mode and larval stage, although it is not confined to fledgling hackers.

/H-C-F/

n. Mnemonic for Halt and Catch Fire, any of several undocumented and semi-mythical machine instructions with destructive side-effects, supposedly included for test purposes on several well-known architectures going as far back as the IBM 360. The MC6800 microprocessor was the first for which the HCF opcode became widely known. This instruction caused the processor to toggle a subset of the bus lines as rapidly as it could; in some configurations this can actually cause lines to burn up.