Data Representation

Question 1

Name the order of size (smallest first) for storage terms

Answer 1

Bit, Byte, kilobyte, Megabyte, Gigabyte, Terabyte, Petabyte

Question 2

State the three steps of converting negative numbers into binary.

Answer 2

Create positive number
Invert all 0s and 1s
Add 1 to right hand bit

Question 3

What two parts of a real number does a computer store?

Answer 3

Mantissa and Exponent

Question 4

State an advantage of using floating point representation.

Answer 4

Takes up less space for storing large numbers and allows real numbers to be stored

Question 5

State a disadvantage of using floating point representation.

Answer 5

The computer must split its storage space between mantissa and exponent. This can cause rounding errors

Question 6

What are the four sizes of floating point numbers defined as?

Answer 6

16 bit- Half precision
32 bit- Single precision
64 bit- Double precision
128 bit - Quadruple precision

Question 7

What is the structure (sign, exponent and mantissa) of a SINGLE precision number

Answer 7

Sign - 1 bit
Exponent - 8 bits
Mantissa - 23 bits

Question 8

State three advantages of using the binary system?

Answer 8

0s and 1s are easily represented in digital
Dropping voltage does not affect the data
Less rules of arithmetic

Question 9

What increases with the number of bits allocated to the mantissa

Answer 9

An increased accuracy or precision

Question 10

What increases with the number of bits allocated to the exponent?

Answer 10

An increased range

Question 11

How do computers store integers?

Answer 11

Binary representation

Question 12

How much storage does a single ASCII character take up

Answer 12

1 byte (8bits)

Question 13

State a disadvantage of using ASCII

Answer 13

Representing symbols from other languages

Question 14

How many characters can Unicode represent compared to ASCII?

Answer 14

Unicode - 65536

ASCII- 255

Question 15

State two advantages of using Unicode

Answer 15

Can represent more symbols

Can represent more languages

Question 16

What is the difference between analogue and digital?

Answer 16

Analogue can have values of max and min

Digital is simply made up of 1s and 0s

Question 17

State 5 factors that affect file size of a video.

Answer 17

Movie Length
Frame Rate
Resolution
Sound bitrate
Movie Format

Question 18

What two things happen when sampling depth/frequency is increased?

Answer 18

Quality increases/ file size increases

Question 19

Name types of video formats

Answer 19

Flv
Ogg
Mov
Wmc
Mpg/Mp4

Question 20

What is the difference between the number of colours AND bit depth in monochrome and those in True colour

Answer 20

Monochrome - 1 bit depth, 2 colours

True Colour - 24 bit, 16777216 colours

Question 21

What happens when you increase the bit depth of an image

Answer 21

There is a higher colour depth

The file size increases

Question 22

State advantages of vector over bitmap

Answer 22

Vector is resolution independent
Not blurred by resizing
Objects can be selected and edited
File size is smaller

Question 23

State two disadvantages of vector graphics

Answer 23

Requires specific vector packages to create

Cannot represent photo realistic images

Question 24

State advantages of bitmap graphics

Answer 24

Image can have effects applied to them

Represent photos

Question 25

State disadvantages of bitmap

Answer 25

Large storage space

Blurred with resizing

Question 26

State 5 bitmap file formats

Answer 26

Bmp
Gif
Png
Tiff
Jpeg

Question 27

State the range of values that two’s complement could store using 8 bits

Answer 27

-128 to 127

Question 28

Describe the difference between lossy and lossless compression

Answer 28

Lossless may be uncompressed, recreating the original file with all the original data
Lossy file is compressed, data is permanently lost