b | bit | |
B | Byte | 1Byte = 8 bits |
word | Depends on computer architecture. 1 word = 32 bits in older desktop computers and laptops. 1 word = 64 bits in present desktop computers and laptops. |
While bytes (MB, GB, TB) are used to describe memory capacity and file sizes,
bits are used while discussing bandwidth, the speed of transmitting information (Mb/sec).
k | kilo | 1000 | 103 | 1000 |
K | binary kilo | 1024 | 210 | 1024 |
m | mega | 1000*1000 | 106 | 1,000,000 |
M | binary mega | 1024*1024 | 220 | 1,048,576 |
g | giga | 1000*1000*1000 | 109 | 1,000,000,000 |
G | binary giga | 1024*1024*1024 | 230 | 1,073,741,824 |
t | tera | 1000*1000*1000*1000 | 1012 | 1,000,000,000,000 |
T | binary tera | 1024*1024*1024*1024 | 240 | 1,099,511,627,776 |
1KB is approximately equal to 1kB (within a 3% error).
1MB is approximately equal to 1mB (within a 5% error).
1GB is approximately equal to 1gB (within a 8% error).
1TB is approximately equal to 1tB (within a 10% error).
The higher the prefix the bigger the relative error while identifying binary
and decimal versions.
Evan higher decimal and binary prefixes are used to describe performance of supercomputers:
peta - 1015
exa - 1018
zetta - 1021
yotta - 1024
See also http://en.wikipedia.org/wiki/Binary_prefix .
Originally published in Standard Output, Vol. 1, No. 3, November 2006.