WhatIs

/H-L-L/

n. [High-Level Language (as opposed to assembler)]

/hər-ˌsüt/

adj. Occasionally used humorously as a synonym for hairy.

/hī-lē/

[Scientific Computation]

/hī mō-bē/

n. The high half of a 512K PDP-10's physical address space; the other half was of course the low moby. This usage has been generalized in a way that has outlasted the PDP-10; for example, at the 1990 Washington D.C. Area Science Fiction Conclave (Disclave), when a miscommunication resulted in two separate wakes being held in commemoration of the shutdown of MIT's last ITS machines, the one on the upper floor was dubbed the 'high moby' and the other the 'low moby'.

/hī bit/

[from 'high-order bit']

n. 

1. The most significant bit in a byte.

2. By extension, the most significant part of something other than a data byte:
"Spare me the whole saga, just give me the high bit."
See also meta bit, hobbit, dread high-bit disease, and compare the mainstream slang bottom line.

/hi-dᵊn flāg/

[scientific computation]

n. An extra option added to a routine without changing the calling sequence. For example, instead of adding an explicit input variable to instruct a routine to give extra diagnostic output, the programmer might just add a test for some otherwise meaningless feature of the existing inputs, such as a negative mass. Liberal use of hidden flags can make a program very hard to debug and understand.

/hek'sit/

n. A hexadecimal digit (0-9, and A-F or a-f). Used by people who claim that there are only *ten* digits, dammit; sixteen-fingered human beings are rather rare, despite what some keyboard designs might seem to imply (see space-cadet keyboard).

/hek-sə-ˈdes-məl/

n. Base 16. Coined in the early 1960s to replace earlier sexadecimal, which was too racy and amusing for stuffy IBM, and later adopted by the rest of the industry.

/heks/

n. 1. Short for hexadecimal, base 16.

2. A 6-pack of anything (compare quad, sense 2). Neither usage has anything to do with magic or black art, though the pun is appreciated and occasionally used by hackers.

True story: As a joke, some hackers once offered some surplus ICs for sale to be worn as protective amulets against hostile magic. The chips were, of course, hex inverters.

/hə-ˈlō wər(-ə)ld/

interj. 

1. The canonical minimal test message in the C/UNIX universe.