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#Post#: 130--------------------------------------------------
Gigabytes, Megabytes, Kilobytes etc
By: Intelinside Date: October 19, 2012, 2:28 pm
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Bits, Bytes, Mega, Giga, Tera (explained)
1 bit = a 1 or 0 (b)
4 bits = 1 nybble (?)
8 bits = 1 byte (B)
1024 bytes = 1 Kilobyte (KB)
1024 Kilobytes = 1 Megabyte (MB)
1024 Megabytes = 1 Gigabyte (GB)
1024 Gigabytes = 1 Terabyte (TB)
Common prefixes:
- kilo, meaning 1,000. (one thousand) 10^3 (Kilometer, 1,000
meters)
- mega, meaning 1,000,000. (one million) 10^6 (Megawatt,
1,000,000 watts)
- giga, meaning 1,000,000,000 (one billion) 10^9 (Gig watt,
1,000,000,000 watts)
- tera, meaning 1,000,000,000,000 (one trillion) 10^12
The smallest amount of transfer is one bit. It holds the value
of a 1, or a 0. (Binary coding). Eight of these 1's and zeroes
are called a byte.
Why eight? The earliest computers could only send 8 bits at a
time, it was only natural to start writing code in sets of 8
bits. This came to be called a byte.
A bit is represented with a lowercase "b," whereas a byte is
represented with an uppercase "b" (B). So Kb is kilobits, and KB
is kilobytes. A kilobyte is eight times larger than a kilobit.
A simple 1 or 0, times eight of these 1's and 0's put together
is a byte. The string of code: 10010101 is exactly one byte. So
a small gif image, about 4 KB has about 4000 lines of 8 1's and
0's. Since there are 8 per line, that's over (4000 x 8 ) 32,000
1's and 0's just for a single gif image.
How many bytes are in a kilobyte (KB)? One may think it's 1000
bytes, but its really 1024. Why is this so? It turns out that
our early computer engineers, who dealt with the tiniest amounts
of storage, noticed that 2^10 (1024) was very close to 10^3
(1000); so based on the prefix kilo, for 1000, they created the
KB. (You may have heard of kilometers (Km) which is 1000
meters). So in actuality, one KB is really 1024 bytes, not 1000.
It's a small difference, but it adds up over a while.
The MB, or megabyte, mega meaning one million. Seems logical
that one mega (million) byte would be 1,000,000 (one million)
bytes. It's not however. One megabyte is 1024 x 1024 bytes. 1024
kilobytes is called one Megabyte. So one kilobyte is actually
1024 bytes, and 1024 of those is (1024 x 1024) 1048576 bytes. In
short, one Megabyte is really 1,048,576 bytes.
There is a difference of about 48 KB, which is a decent amount.
If you have a calculator, you will notice that there is actually
a 47KB difference. There is a difference of 48,576 bytes,
divided by 1024, and you get the amount of real kilobytes...
47.4375
All of this really comes into play when you deal with Gigabytes,
or roughly one billion bytes. One real Gigabyte is actually 1024
bytes x 1024 bytes x 1024 bytes...1,073,741,824. However, most
people like to simplify this by simply saying that one Gigabyte
is only 1,000,000,000 (one billion) bytes; which makes sense
because the prefix Giga means one billion.
A few examples (don't hold me to these)
About 130,000 pages of text (200 words per page, no pictures,
mono text) Your nice new 500Gb drive= 65 million pages
About 220 4.5MB photos from a 10megapixel camera
Your nice new 500Gb drive= 110,000 pictures
About 250 average MP3 audio files
Your nice new 500Gb drive=
125,000 music files
About 1 1/2 compressed avi video files (full length feature
films) Your nice new 500Gb drive= 700 - 750
feature films
About 1/4 of an uncompressed video film purchased on DVD
Your nice new 500Gb drive= 100 DVD films in
original format and in fact could be much less than this
Double all these figures for the new Terabyte backup drive that
you will need to buy to back up all this data.
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