Data can arise is different formats for example
numbers, text, still images, moving images or sound.
Images: Images can be stored as
bitmap or vector graphics.
Numbers: Coding systems exist for different types of numbers: integers
(whole numbers); real numbers (numbers with a fractional part);
currency (pounds and pence); Boolean (0 or 1).
Moving Images: Animations consist of images (or frames) stored together and displayed
one after the other. The more frames and the smaller the change between frames, the more
realistic is the effect of the animation. An animation can take up a lot of storage space.
Sound: Sound has to be sampled at regular intervals. The
sampling rate is the number of times that the wave is sampled
for a given time period. Data compression techniques are used
to reduce the amount of storage space required.
Direct data capture is the collection of data
for a particular purpose.
Example: reading journey details from the magnetic
stripe on a train ticket when a passenger enters the
platform to check that the ticket is valid
Indirect data capture is the collection of
data as a by-product from another purpose.
Example: using the collected data on journeys to
calculate statistics on train use
Whatever type of data being input, computers store and process data using
binary numbers. A single unit in binary is called a bit which stands for binary digit.
1 byte = 8 bits
Computer memory is measured in Bytes. One byte is
made up of eight bits. One byte can store one character.