Distrubuted Computing & Databases

Question 1

Define Distributed Computing

Answer 1

S series of computers are networked together (1) each working on solving the same problem/a problem/one problem (1) sharing same bandwidth/data processing. (1)

Question 2

Example of Distributed Computing

Answer 2

SETI - Using radio waves in an attempt to detect intelligent life outside Earth.

Question 3

Advantages of Distributed Computing

Answer 3

—Reduces cost because an expensive powerful computer such as a supercomputer is not needed

—Can pass work to computers anywhere in the world using the Internet

—Improved performance as each computer can work on part of the data

—To get more processing power you just need to add more PCs.

Question 4

Disadvantages of Distributed Computing

Answer 4

—Issues with the security of data spread out on so many different computers.

—Heavy reliance on networks and communications which may not always be reliable

—Increased costs owing to the use of expensive communication lines

Question 5

Define Distributed Databases

Answer 5

A distributed database has data stored on a number of computers at different locations (1) but appears as one logical database

Question 6

Advantages of Distributed Databases

Answer 6

—If data lost on central site it could be reduplicated from local site.

—Allows sharing of the data and the results of processing the data.

—New locations can be added to the database without the need for rewriting the entire database.

—Faster response to user queries of the database.

—Non-dependence on one central huge store of data.

—Easy to backup and copy data from one server to another.

—If one server fails then the other servers can be used.

—Reduces network traffic as local queries can be performed using the data on the local server.

Question 7

Disadvantages of Distributed Databases

Answer 7

—Software more complex than a centralised database system.

—If data is transferred it presents more of a security risk from hackers.

—As all the data is not stored in one location if a local site does not have adequate backup then this data might be lost to others.

—If data is stored and updated in more than one place there is an increased chance of data inconsistency.

—Heavy reliance on networks and communications which may not always be reliable.

—Security issues particularly if sensitive personal data is being transferred.

—If one of the links to a server failed then the data could not be obtained from that server.

—Increased costs owing to the use of expensive communication lines. NOT just costs.