From
Webopedia:
A petaflop is the ability of a computer to do one quadrillion floating point operations per second (FLOPS.) Additionally, a petaflop can be measured as “one thousand teraflops”. A petaflop computer would require a massive number of computers working in parallel on the same problem. Applications might include real-time nuclear magnetic resonance imaging during surgery or even astrophysical simulation.
From
Wikipedia:
In physics and mathematics, peta- (symbol: P) is a prefix in the SI (system of units) denoting 10^15, or 1 000 000 000 000 000. For example:
1 petametre = 10^15 metres
1 petasecond = 10^15 seconds
Adopted in 1975, it comes from the Greek πέντε, meaning five, because it is equal to 10005. It is based on the model of tera- (from Greek τέρας = 'monster', but looking like tetra- from the Greek for \"four\" with a letter missing, and so peta-, coming from penta-, omits the third letter, n.
In computer science peta- can sometimes mean 1 125 899 906 842 624 (10245 or 250), instead of 1 000 000 000 000 000, especially when used to prefix the byte, giving a petabyte. To resolve this ambiguity, the term pebibyte has been suggested to mean 250 bytes. However, this term is not yet widely used.
See table for other \"useful\" terms of scientific measurement
EDIT: changed occurances of 1015 to 10^15