PEEK

The command in most microcomputer BASICs for reading

memory contents (a byte) at an absolute address. POKE is the

corresponding command to write a value to an absolute address.

This is often extended to mean the corresponding constructs in

any High Level Language.

Much hacking on small microcomputers without MMUs consists

of "peek"ing around memory, more or less at random, to find

the location where the system keeps interesting stuff. Long

(and variably accurate) lists of such addresses for various

computers circulate (see interrupt list). The results of

"poke"s at these addresses may be highly useful, mildly

amusing, useless but neat, or total lossage (see killerpoke).

Since a real operating system provides useful, higher-level

services for the tasks commonly performed with peeks and pokes

on micros, and real languages tend not to encourage low-level

memory groveling, a question like "How do I do a peek in C?"

is diagnostic of the newbie. Of course, operating system

kernels often have to do exactly this; a real C hacker

would unhesitatingly, if unportably, assign an absolute

address to a pointer variable and indirect through it.

[Jargon File]

(1995-01-31)