Parkinson's Law of Data

"Data expands to fill the space available for storage"; buying

more memory encourages the use of more memory-intensive

techniques. It has been observed over the last 10 years that

the memory usage of evolving systems tends to double roughly

once every 18 months. Fortunately, memory density available

for constant dollars also tends to double about once every 12

months (see Moore's Law); unfortunately, the laws of physics

guarantee that the latter cannot continue indefinitely.

[Jargon File]