Web and presentation software

Question 1

what is the purpose of a file extension

Answer 1

so the user can easily tell what type of data it is and which application will open the file

Question 2

what detail are recorded when a file is saved

Answer 2

name, size, date and time, application used

Question 3

what are the problems associated with saving data

Answer 3

storage devices have limited capacity, large files take a long time to load, if data is transmitted across a network, large files take longer

Question 4

what is data compression

Answer 4

used to make a file smaller when stored or sent over a network, needs to be de-compressed before being used.

Question 5

advantages of data compression

Answer 5

files take up less space when stored, files reached their destination quicker when sent over a network or up/downloaded

Question 6

disadvantages of data compression

Answer 6

precision can be lost, it isn’t always possible to return to the uncompressed state

Question 7

how can sounds be saved

Answer 7

.wav (wave), not compressed, gives max quality.
.wma (Windows Media Audio), compressed without loss of quality
.mp3 (Moving Pictures Expert Group)

Question 8

how can images be saved

Answer 8

.bmp, made up of thousands of pixels (bitmaps)
.jpeg, can allow 10:1 compression with little loss of quality
.gif, only uses 256 colours