All About Bits and Bytes
Data is made
up of bits and bytes. A bit is the smallest piece of information
that can be created or stored. A bit can either be a ?0? or a ?1? in
value.
A byte is made up of 8 bits. The 8 bits in a byte are stored in various
combinations (up to 256 possible) to represent different characters,
symbols and program commands. For example, in a text document, each
displayed character is represented by a byte. Non-printing characters
that specify things such as formatting and graphics are all represented
by a series of bytes.
A file is made up of hundreds or many thousands of bytes. Large image
files may be millions of bytes. So for convenience, we introduce the
scientific notation to represent larger numbers:
-
Kilo
= thousand = 1,000
-
Mega
= million = 1,000,000 or 1000 Kilo
-
Giga
= billion = 1,000,000,000 or 1000 Mega
So,
-
One Kilobyte
(or KB) is 1,000 Bytes.
-
One Megabyte
(or MB) is 1,000,000 Bytes or 1,000 KB
-
One Gigabyte
(or GB) is 1,000,000,000 Bytes or 1,000 MB or 1,000,000 KB
In comparison:
-
Your PC
random access memory (or RAM) may store from 64 MB to 512 MB or more.
-
Your PC hard
drive capacity may be 20 GB to 120 GB or more.
-
A memory card
used in a digital camera stores from 8 MB to 256 MB or more.
-
A ?Zip? drive
stores from 100 MB to 750 MB.
-
A CD-ROM
stores just over 700 MB.
-
A DVD-R
stores 4.7 GB.
-
A floppy
drive (A:) stores 1.44 MB. Not very much in comparison to other
storage media!
To put this in the context of file size:
-
A typical
word processing file may be anywhere from 20 KB to over 100KB in
size.
-
A digital
image file from a digital camera may be 200 KB to 2 MB in size.
And in the context of network or connection rates:
-
A dial up
modem operates at 56 Kbits per second, which is equal to 7 KBytes per
second remember, there are 8 bits to a byte).
-
A broadband
modem (cable or DSL) operates at 128 Kbits to 2 Mbits per second;
equal to from 16 KBytes/s to over 250 KBytes/s.
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Digital
cameras
