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AS IT: Information
Systems and
Communication:


Revision Guide




Hayley Van-Heerden 12.6

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Data
Raw facts and figures
Can contain any character
Has no meaning

Data needs a meaning and context to be classed as
information


Data +meaning +context = information
Conveying information:
PROS CONS
Text Can convey lots of info Can be long winded, have
to know the language,
could be illiterate…

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Knowledge is the result of interpreting
information, to build up sets of rules based on
probabilities not certainties.
Eg. `Windows 7 is an operating system' this is not
knowledge, because you would have to understand what an
operating system is. Therefore it is information.



Data Types
Boolean: a data type…

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Data Sources
Direct ­ from its original source
Indirect ­ used for a different purpose or a different
organisation using the data compared to who collected it.

Static ­ where the data doesn't and can't change once it
has been created. This includes books and CDs.

Dynamic ­ where once…

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Codes can be easier to Difficult to track errors
remember


Validation Methods
Validation is a check performed by the computer as data is being
entered. It tries to prevent the entry of data which does not conform
to pre-set rules.

Range Checks
Sets upper and lower boundaries for data, so…

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(format check or input mask) Allows you to check against a set
combination of numbers and letters (ie 22FFF) so if you type
F2098, it is classed as incorrect.

Verification Methods
Verification is making sure that information on a source document
(eg paper) is the same as information on the…

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The costs of producing information
1. Hardware
2. Software
3. Consumables
4. Personnel
Hardware:- Anything used in a computer system,
including a monitor, printer and keyboard. The costs
of hardware include the intial cost of purchasing,
repair, maintenance and upgrades
Software:- Anything used inside of the computer,
including programs. The…

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INPUT/OUTPUT DIAGRAM....




Input ­ taking external information and entering it into
the system.

Processing ­ can include sorting, searching or performing
calculations on the data.

Storage ­ where data is held, and is still in the system after
partial or complete processing.

Output ­ Taking processed information out of the…

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