ICT- Chapter 1_2

ICT- Chapter 1_2

1. Data

   • Backing up and archiving
   • Dynamic and Static
     • Dynamic
       • Data that can change. It is data that is stored in an electronic format and will change as circumstances change, this could be data stored on the internet
         • Flight departure and arrival information
     • Static
       • Static data does not change, It would have been produced at a particular time on a particular date and it is then permanent.
         • Books or magazines
   • Input
     • Data that is put into the computer system, hardware such as a plug does not count as input.
   • Processing
     • The processor will manipulate the data by performing calculations or sorting the data or transforming it in some other way before it is ready to be stored or output. Once the data is processed it transforms into information
   • Output
     • Information which can be put out of the computer system e.g. display monitor or speakers etc
   • Storage
     • Data can be stored in two forms- temporarily while processing e.g. RAM or longer term on secondary storage disks.
   • Feedback
     • Feedback takes place when the output of a system affects the input of the same system.

2. Information

   • Quality of information
     • Accuracy
       • Must be correct
     • Relevance
       • Must be relevant for the purpose
     • Age
       • Must be up to date
     • Completeness
       • All the data that is required must be available
     • Presentation
       • Must be easy to understand
     • Level of detail
       • Combination of completeness and relevance
   • Costs
     • Hardware
       • This covers any equipment that is required to collect or produce information.
         • Computer, printer, scanner
     • Software
       • Required to produce information which will involve the collection and processing of data.
   • Methods to convey information
     • Text
       • Advantages
         • Can be read even if its noisy
         • Explanations can be given
       • Disadvantages
         • Language barriers
         • Blind people can't read it
     • Pictures
       • Advantages
         • No language barriers
         • Can be seen even if its noisy
       • Disadvantages
         • Not everybody may know the meaning
         • Cannot give explanations
     • Sound
       • Disadvantages
         • Difficult to hear in a noisy environment
         • Not everybody will want to listen
       • Advantages
         • Grabs attention
         • Do not need to be near a display to hear it
     • LED
       • Disadvantages
         • Can only be seen if you are close to them.
         • They don't mean anything so they need texts and images to show what they mean.
       • Advantages
         • Cheap
         • Use very little power and space.
     • Animation
       • Disadvantages
         • Doesn't show sound
         • Only shows steps so some information can be left out
       • Advantages
         • Can convey a meaning effectiively
         • Not dependent on someone knowing a specific language
     • Videos
       • Disdvantages
         • Time consuming to produce.
         • Require a screen and speakers
       • Advantages
         • Both sound and video
         • Shows exactly what you need to do

3. Key terms

   • Data
     • Unprocessed raw facts and figures that have no meaning.
   • Information
     • Information is data that has meaning, structure and context.
       • Structure is when data is presented in a particular way
         • Structure e,g. 2100 is $21.00
       • Context e.g. 09876543210 is a phone number
       • Meaning e.g. 38 is the age of my sister
   • Knowledge
     • Knowledge is the application of information to a situation.
     • Knowledge is based upon a set of rules.

4. Encoding

   • Numerical representation
     • When words and descriptions are replaced by numbers
   • Abbreviations
     • Replacing words or descriptions with letters that link to the words or descriptions
   • Advantages and Disadvantages
   • Value judgements
     • These are used in questionnaires when someone is asked what they think about a particular thing.

5. Validation methods

   • Type Check
     • Will check to see that the data is the correct data type.
   • Length Check
     • Ensures that the data is a minimum, maximum a specific length
   • Presence check
     • Checks that some data has been entered for a particular field so that a field isn't left empty
   • Picture/ format check
     • A format check will ensure that data entered matches a particular pattern
   • Range Check
     • A Range Check will ensure that the data is within an acceptable range. There will be a lower limit and a higher limit
   • Lookup in list
     • Checks to see if the data entered exists in a list
   • Check digit
     • An extra digit added to the end of the main data, this is a result of a calculation out on the original data. It will then compare the check digit it is expecting with the one that was entered into the system. If they match then it's valid, if they don't match then it's not valid.
   • Validation is a process that takes place when data is input into a computer system, the computer will check to see if the data is acceptable to the system

6. Verification is the process of checking that data has been transferred from its original source to the computer correctly.

   • Double entry
     • Asking for the data to be entered twice
       • e.g. having to create a password
   • Proof reading
     • Visually checking that the data entered on the computer matches the original source of data

7. Data types

   • Boolean
     • This can only have two values, true or false etc
   • Real
     • This includes decimal numbers.
   • Integer
     • These are whole numbers, there are no decimals or fractions in this type of data.
   • String
     • A set or list of letters, symbols, characters and/or numbers.
   • Date/time

8. Sources of Data

   • Direct
     • If data is used for the same purpose it was originally collected for then the source is classed as a direct source of data
       • Phone numbers- to calculate a mobile phone user's bill- to calculate and create bill for a mobile phone user
     • Advantages and disadvantages
       • The original data that is collected is the data that is needed
       • It can be costly to collect original data
       • It can take time to collect the original data.
   • Indirect
     • When the purpose the data is used for is not the same as the purpose as to why it was collected
       • Phone numbers- to calculate a mobile phone users bill- used by the police to determine if a driver was using their phone whilst driving
     • Advantages and disadvantages
       • There is no need to wait for the data to be collected because it is already available
       • The data may not meet all of the needs of the new purpose.