Introduction
A computer can be broken down into four logical areas, as shown in this diagram:
A diagrammatic representation of the four parts of a computer.
Computers must have data to work on.
Data must be moved from outside the computer and put into it.
The methods of getting data into a computer have traditionally been discussed by talking about using
manual methods of data input
or automatic methods of data input.
This is where data is input directly into the computer from the input device without any user intervention.
A Sensor collects physical real world information and puts it into the computer as data
(Light level sensor (light), digital thermometer (heat), Infra red Burglar Alarm (movement)
Optical Mark Recognition (OMR):
Opitcal Character Recognition (OCR):
Shapes are recognized by the computer
and compared to shapes stored in the computer's memory
Used to read the written amount on cheques
shaded boxes represent data on a specific area of the form
and read by an OMR reader machine
For example old style school registers or Lottery ticket
The position of the shaded boxes must be very precise or the data will be misread
Investigate other methods of automatic data entry...
Bar Code Scanner:
as used in Supermarkets and also on most products purchased
Reads light and dark parallel lines. (see Diagram right)
the dark lines are read in pairs
Magnetic Ink Character Reader (MICR):
Characters are printed on a paper form using special magnetized ink,
these can be read by special devices in the future
e.g. Used on Passport information and (see right) on
printed cheques to determine sort code and bank account number
The computer will then look this up to retrieve the product information
they correspond to digits that are converted to a product code or other information to the computer.