Online Computer Terms Dictionary - P

peta-

prefix

petabyte

<unit> 2^50 = 1,125,899,906,842,624 bytes = 1024 terabytes or roughly 10^15 bytes.

See prefix.

(1996-08-12)

petaflops

<unit> 10^15 flops or 1000 teraflops. No computer has achieved this performance yet.

(1997-07-21)

petdingo

<tool> An Estelle to C++ translator.

(1997-01-24)

Peter Chen

<person> The developer of the Entity-Relationship model.

(1995-02-07)

Petri net

<parallel, simulation> A directed, bipartite graph in which nodes are either "places" (represented by circles) or "transitions" (represented by rectangles), invented by Carl Adam Petri. A Petri net is marked by placing "tokens" on places. When all the places with arcs to a transition (its input places) have a token, the transition "fires", removing a token from each input place and adding a token to each place pointed to by the transition (its output places).

Petri nets are used to model concurrent systems, particularly network protocols.

Variants on the basic idea include the coloured Petri Net, Time Petri Net, Timed Petri Net, Stochastic Petri Net, and Predicate Transition Net.

FAQ.

(1996-09-10)

PETSCII

<character> /pet'skee/ PET ASCII. The variation (many would say perversion) of the ASCII character set used by the Commodore Business Machines' PET series of personal computers and the later Commodore 64, Commodore 16, and Commodore 128 computers. The PETSCII set used left-arrow and up-arrow (as in old-style ASCII) instead of underscore and caret, placed the unshifted alphabet at positions 65--90, put the shifted alphabet at positions 193--218, and added graphic characters.

[Jargon File]

(1995-10-29)