|Table of contents|
Data in a digital age
Bit (b) = 0/1 Byte (B) = 8 bits (used to represent one character (e.g. A, B, C, etc...)
1 Kilo byte (KB) = 1024 bytes (this is why hard disks have a different size when you look up their technical data)
- 1 024 Bytes = 1 Kilobyte (2^10 / 10^3)
- 1 024 Kilobytes = 1 Megabyte (2^20 / 10^6) = 1 048 576 Bytes
- 1 024 Megabytes = 1 Gigabyte (2^30 / 10^9) = 1 073 741 824 Bytes
- 1 024 Gigabytes = 1 Terabyte (2^40 / 10^12)
- 1 024 Terabytes = 1 Petabyte (2^50 / 10^15)
- 1 024 Petabytes = 1 Exabyte (2^60 / 10^18)
- 1 024 Exabytes = 1 Zettabyte (2^70 / 10^21)
- 1 024 Zetabytes = 1 Yottabyte (2^80 / 10^24)
(In 1993 Morgan Burke proposed adding graucho (2^90 ) and harpo (2^100 ). This has not been formally accepted.)
- -) I hear there's a band called 1023MB they haven't had any gigs yet !!
Text represented electronically
Consider a light switch. The light can represent two states: ON and OFF. In computer terms the light switch would be called a BIT.
Now think of two switches attached to lights. We can now represent 4 states: off-off (00), off-on (01), on-off (1-0) and on-on (1-1). If we assign letter to the four states 00=A, 01=B, 10=C and 11=D we could send a message to a distant place (so long as they could see our lights. So if we sent 10 00 11, the message would read CAD.
Looking at the keyboard, there are lots of letters to display (a-z, A-Z, 0-9, and the special ones like !@#$ ). Development of a code suitable for electronic transmission was started around 1960, and was called the American Standard Code for Information Interchange (ASCII). ASCII uses 8 bits to represent characters (Glyphs), and this is known as a BYTE. (ASCII,2010))For example:
For a complete list go to the Wikipedia ASCII Page 
How many bytes on an A4 page?
- Non-proportional font, of about 10 pitch;
- Paper width = 80 characters
- Paper height = 66 lines
- Margins of;
- top = 10 lines,
- bottom = 6 lines
- sides = 10 characters
- 60 characters x 50 lines
- = 3,000 characters
- = (approx. 3 Kilobytes)
How may bytes in a phone book?
For Napier/Hastings (population: approx. 100,000)
- Characters per line 40
- Lines per page x 100
- Number of columns x 5
- Number of pages x 190
|Total characters - .....?|
|3,800,000 = 3.8 MB|
How does a computer handle those characters found in other languages??
Just to complete the discussion, How does a computer handle those characters found in other languages? UNICODE was developed from around 1987, and allows for several coding schemes the most common being the Unicode Transformation Format-8 (UTF-8). UTF-8 uses from 1 to 4 bytes, with the first byte for ASCII (to remain compatible), and can represent most modern (e.g. Hebrew, Chinese, Russian), and ancient languages.(Unicode, 2010)
Some other comparisons (sizes are approximate)
For Vodaphone mobile there is a casual rate $1 per day up to 10MB (only on day of use) (Vodaphone, 2010).
- 10MB roughly =
- 100 web pages,
- 300 text emails,
- 12 minutes YouTube, or
- 100 Facebook photos.
1GB of online activity is equal to (Xtra, 2007)
- 200,000 text-only emails
- 8,300 average web pages
- 200 music files (3 minute tracks)
- 50 hours Online games
- 32 three-minute movie trailers
- 1 movie (saved as DivX or WMV around 640MB)
- a 3.5 MB in size file takes
- approximately 9 minutes to download using a 56.6 Kbit/s dial-up modem,
- about 20 seconds on a 1.5Mbit/s broadband link
- A three hour movie (FXNetworks, n.d.)
- 7 seconds on 10Gbps.
- FXNetworks (n.d.)in NZ can offer clients
- 40 Gbps lines
- capable of delivering 360Gbps
- 1900Gbps (1.9Tbps) possible
- 1 MegaPixel: Photo
- 2 MegaPixel: Photo (suitable for 6" x 4" print at 300dots per inch)
- 3 MPixel: Photo (suitable for 7" x 5" print and is ok for A4). A 3MPixel camera may have "3.1 megapixels" (2048 × 1536 = 3,145,728) sensor elements (Wikipedia, 2009)but the size on disk of the image can be reduced through "compression" techniques.
- 8 MPixel: Photo (suitable for poster print). 8 MPixel camera 3266 by 2450 sensors = 8,001,700
- 400MB: TV program (using DivX codec)
- 640MB: CD-ROM
- Full length Movie(Using DivX Codec)(fits on normal CD)
- 4.7GB: DVD-ROM (single layer)
- 1TeraByte: Hard Disk Drive (2009 External USB $250)
And some examples
Example: Bus seat numbering
|The photo above show the numbering system in a luxury bus. Can you work out what the pattern (if any there is) and why it has been numbered this way.|
|A random numbering system
- Wesch, M. (2007) Information Revolution, YouTube. Retrieved February 12, 2009 from http://www.youtube.com/watch?v=-4CV05HyAbM
- ASCII. (2010, February 9). In Wikipedia, The Free Encyclopedia. Retrieved 08:28, February 25, 2010, from http://en.wikipedia.org/w/index.php?title=ASCII&oldid=34290988
- Unicode. (2010, February 23). In Wikipedia, The Free Encyclopedia. Retrieved 09:05, February 25, 2010, from http://en.wikipedia.org/w/index.php?title=Unicode&oldid=345809172
- Vodaphone (2010). Internet on your mobile. Retrieved February 21, 2010 from http://www.vodafone.co.nz/mobile-data/mobile-web.jsp?
- xtra (2007) Broadband usage. Wireless broadband user guide
- FXNetworks (n.d.) Retrieved February 12, 2009 from http://www.fx.net.nz/
- Wikipedia (2009). Pixel. Retrieved January 22, 2009 from http://en.wikipedia.org/wiki/Pixel
- Design215 (2008). Design215 megapixels comparison and maximum print size charts. Retrieved January 22, 2009 from http://www.design215.com/toolbox/megapixels.php
- Forret, P. (n.d.) Megapixel Calculator - digital camera resolution. Retrieved February 21, 2010 from http://web.forret.com/tools/megapixel.asp