4b. Applications of ICT Flashcards
A laptop can be used for only about three hours when not connected to a power supply. But what potential advances in technology could change this?
The development of larger solid state storage rather than hard disks will mean less battery power is required in the future. Solar powered cells may be produced that can be integrated into the lid of the laptop to charge the battery. Longer life batteries could be developed in the future.
Mobile phone screen sizes are currently too small to look at web pages effectively because the whole page cannot be seen without the font size being too small. But what potential advances in technology could change this?
Fold up screens may be developed in the future meaning that a mobile phone’s screen could be folded away and then opened up when needed.
Wireless network signals have difficult penetrating walls and other structures meaning that some areas of buildings may suffer from poor connectivity. But what potential advances in technology could change this?
Developments may take place with wireless networks frequencies that are easily able to penetrate walls meaning that wireless networks can be extended to cover much larger areas.
Credit cards require the owner to remember a PIN which can be problematic if the owner has several PINs and passwords to remember. But what potential advances in technology could change this?
Biometric identification may be used in the future which may mean that people ned not even carry a credit card because they could simply present their finger or eye and this would uniquely identify them.
What is a partitioned database?
Has different parts of the data stored at different sites. No single site stores all the data. A ‘site’ can be a server at a particular location or a single computer. All connected together on a network.
What is the difference between horizontal and vertical partitioned databases?
Horizontal means it is based on records. Vertical means it is based on fields.
What is a replicated database?
They are copied in their entirety at each site within the network.
What is a centralised database?
It is only stored in one location.
Discuss partitioned databases.
Less storage space is required for each ‘site’ as the data is across several locations. Might take longer to run a query for data held at another site. But would be quick for the ones at that server. The design is very complex and requires highly trained specialists to create and maintain the database. A back up system needs to be in place at all sites.
Discuss replicated databases.
Lots more storage space is required as the whole database is at each site. This can be very expensive. Queries are quick as all data is already at the location. A balance has to be found between having up to date data and reducing the amount of traffic across communication links, so whether they update the server every few hours/few minutes. Can easily add extra fields or tables that are useful for the local site without any problems. Still complex to set up and requires trained specialists. Each replica naturally backs it up. Back ups still need to be taken in at least one of the sites in case data becomes corrupted across the whole system.
Discuss centralised databases with local indexes.
Storage is required only in the location for the centralised database, but will require multi user access to data so isn’t cheap. Powerful processors will also be required. Queries should be fast. All index rely on one server, so if that breaks down none of them can retrieve the information. No sites have any control over the configuration of the database. Quite straight forward design. They need to back up at the main server by changing tapes daily. They’ll also require daily tests to make sure back ups can be restored.
What security risk is there with distributed databases?
Because there is a lot of data moving around, it is susceptible to hackers. The data needs to be highly encrypted.
Give 6 examples of security measures that could be taken out.
Physical security, user level security, anti virus software, firewall, anti spyware software and encryption.
What is an expert system/knowledge based system?
A computer program made up of knowledge and rules that can be used to diagnose a problem. They’re used for decision making and recommending particular courses of action.
What is an example of an expert system?
On the NHS website - experts (doctors) will have collated their knowledge about illnesses and the symptoms of those illnesses so that a user can enter information to figure out what illness they may have.
