0417/01

Question 1

Explain what is meant by GPS

Answer 1

– Global Positioning System
– space-based navigation system
– typically four satellites must be visible to the receiver
– calculates the distance from a receiver to the satellite
– calculates the position of the receiver

Question 2

Compare and contrast the use of magnetic tapes with removable magnetic disks to make network
server backups

Answer 2

• both can be stored well away from the server…
  – ….in the event of fire they will be secure
  – tapes are cheaper per bit
  – tapes are more compact than a portable hard disk for the same memory
  – it is quicker to access lost work using disks
  – disks would make it quicker to restore the system
  – tapes are less prone to data loss and mechanical failure
  – both can store very large amounts of data
  – both have very fast data transfer rates

Question 3

(a) Describe how an expert system diagnoses illnesses.

Answer 3

• data is entered using keyboard/touch screen
  – uses interactive interface/asks questions…
  – …based on previous responses
  – inference engine compares data
  – compares data with that held in the knowledge base…
  – …using rules base
  – matches are found
  – system suggests probable illnesses [4]

Question 4

Describe how a microprocessor-controlled burglar alarm system operates, referring to those
sensors

Answer 4

Microprocessor checks input from the user is authentic
Microprocessor continually monitors sensors.
If infra-red sensor reading changes
If pressure greater than pre-set value…
If sound greater than pre-set value…
Microprocessor sends signal to sound alarm
Microprocessor sends signal to flashing light/house lights.
Microprocessor automatically sends message/calls/texts owner

Question 5

data protection act

Answer 5

data must be processed fairly and lawfully
data must be processed for limited purpose
data must be adequate, relevant, and not excessive
data must be accurate and up to date
data must not be held longer than necessary

Question 6

computer modelling: pros/cons

Answer 6

pros
- real thing might
 be expensive
requires large scale of time
too wasteful of material
too vast a scale
imposible to create
- test prediction more easily

cons

• difficult to create exact eventualities
• hardware/software may be expensive
• workers may need to be trained

Question 7

firewall

Answer 7

• monitors incoming/outgoing data traffic
• helps prevent malware getting into computer form internet
• prevents compute accessing undesirable/unauthorized sites
• prevents unauthorized computers using the internet accessing the computer
• keep a list of undesirable sites/IP address
• keep a list of acceptable sites/IP address
• warns you regarding threats/ allow you to accept/reject downloaded programs

Question 8

check on card be4 it is authorised

Answer 8

• card is valid/ card number exists
• card is in date
• PIN entered matches that on card
• checks if card is stolen

Question 9

computer at store and customer bank to complete transaction

Answer 9

1. customer bank contact
2. bank looks up customer account number
3. checks available balance
   daily card limit
4. if sufficient funds, transaction is unauthorized
5. money deducted form customer account into store

Question 10

analysis/ collect info

Answer 10

• examining document
• questionnaires
• interview
• observation

users of current system