Chapter 1

Chapter 1

1. DATA

   • Raw facts and figures
   • Can contain any character
   • Has no meaning
   • Data needs a meaning and context to be classed as information

2. INFORMATION

   • Data +meaning +context = information
   • Conveying information
     • Text
       • PROS:Can convey lots of info
       • CONS: Can be long winded, have to know the language, could be illiterate
     • Graphics
       • PROS: Simple, attractive, interesting, quick
       • CONS: Might take time to understand, cant convey huge amounts of info
     • Video
       • PROS: Interesting, can convey lots of info, easy to follow/understand
       • CONS: Can be quite long winded, adverts ect can’t be rewinded
     • Animation
       • PROS: Entertaining, good way of learning
       • CONS: Might not be taken seriously, not much info can be conveyed in a short time
     • Sound
       • CONS: Not good for the deaf
       • PROS: No need to read, good learning method, good for warnings/sirens
     • LEDS
       • PROS: Can be seen far away, good for caution/warning signs
       • CONS: Not particularly suitable for everyday life, not suitable for long winded text

3. DATA TYPES

   • Boolean
     • a data type which can only conclude with 1 of 2 values, eg yes or no, true or false.
   • Real
     • has decimal places, used where precision is important, eg 10.54.
   • Integer
     • whole numbers only
   • String
     • numbers and letters depending on format, eg 13.46 or 13th Feb 2010.
   • Date/time
     • any alphanumeric character

4. 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 data has been created, it can be changed and updated freely. This includes the internet.

5. Coding of Data

   • Changing original data into a shortened version to store in a computer
   • PROS: Less storage space required Quicker to search info, i.e. ‘wed’ instead of wednesday Aids validation with limited number of codes Codes can be easier to remember
   • CONS: Precision of data coarsened The codes need to be known by the user to be understood Limited number of codes Difficult to track errors

6. Validation Methods

   • Range Checks
     • Sets upper and lower boundaries for data, so that the data entered must be between the 2 boundaries.
   • Type Checks
     • Will not allow you to enter the wrong data type. For example, entering text into a numeric field will be rejected.
   • Presence Checks
     • The computer checks that every essential field has a value entered.
   • Length Checks
     • Ensures the length of data entered cannot be higher than a set number of characters.
   • Lookup Checks
     • Takes a value entered and compares it against a list of values on a separate table. For example, entering a postcode so the system then looks up the postcode to return a list of possible addresses.

7. Verification Methods

   • Double entry
     • Entering data twice, if the computer recognises a difference it informs the user who can then make appropriate. Often used with password entry.
   • Manual verification
     • Proof reading.

8. Backing up and archiving data

   • Backing up is saving data onto more than 1 other system or device (ie hard drive, memory stick), so that if data is lost on 1 system, it can still be accessed elsewhere and isn’t lost.
   • Archiving is storing data which isn’t needed immediately, but so it is still readily available. For example, student user archives

9. The costs of producing information

   • Hardware
     • Anything used in a computer system, including a monitor, printer and keyboard. The costs of hardware include the initial cost of purchasing, repair, maintenance and upgrades
   • Software
     • Anything used inside of the computer, including programs. The costs of software include purchasing licenses, training costs, technical support and upgrades
   • Consumables
     • Items that are consumed (USED UP). The 2 main consumables include paper, and printer ink/toner
   • Personnel
     • People working as part of an organization, such as a school or workplace. Costs include salaries and training