Chapter 1 Data Representation

Question 1

What is the Denary Number System?

Answer 1

A number system based on 10 thus uses 10 unique values from 0 to 9.

Question 2

What is the Binary Number System?

Answer 2

A number system based on 2, thus only has the values 0 or 1.

Question 3

What is the Hexadecimal Number System?

Answer 3

A number System Based on the number 16 thus having numbers 0 to 9 and letters A to F.

Question 4

What is a bit?

Answer 4

A basic unit of information for computers. The word bit comes from the words “Binary Digit”. Binary means Two . 1 or 0 are the only values

Question 5

What is a byte?

Answer 5

8 bits or 2 nibbles

Question 6

Each keyboard character is stored as…

Answer 6

A byte
(Example, A=01000001)

Question 7

What does each letter of the hexadecimal number system represent in denary?

Answer 7

A= 10
B= 11
C= 12
D=13
E=14
F=15

Question 8

Uses of the hexadecimal number system

Answer 8

MAC Addresses
Color codes for HTML
IPv6 addresses
Assembly code
Memory Dumps
Error codes

Question 9

MAC Address

Answer 9

Media-Access Control Address is a 48-bit unique number that identifies the device connected to the internet.
(NN-NN-NN-DD-DD-DD)
The first half is the identity number of the manufacturer
The second is the serial number of the device.

Question 10

HTML

Answer 10

Hyper-Test Markup Language- is a markup language that is used design, write and develop webpages.

Question 11

What is a Markup Language?

Answer 11

A markup language is a language use in the processing, definition and presentation of text ( for example, specifying the color of the text)

Question 12

IP address

Answer 12

An Internet protocol address which gives a unique address for a device connected to the internet.

Question 13

Difference between IPv4 and IPv6

Answer 13

IPv4 is a 32-bit number written in either denary or hexadecimal
IPv6 is a 128-bit number broken into 16-bit chinks written in hexadecimal.

Question 14

Overflow Error

Answer 14

The result of carrying out a calculation that results in a value that is too large for the computer’s allocated word size (8-bit, 16-bit, 32-bit, and so on).

Question 15

Two’s complement

Answer 15

A method of representing negative numbers in binary, when applied to the 8-bit system; the leftmost bit (most significant bit) is given the value -128.

Question 16

What is meant by Logical shift?

Answer 16

An operation that shifts bits to the left or the right on a register. Any bits that are shifted to the left or right are replaced with zeroes.

Question 17

Character Set

Answer 17

A list of characters that have been defined by the computer Hardware and software. The character set is necessary so that the computer can understand human characters

Question 18

ASCII code

Answer 18

A character set for all the characters on a standard keyboard and control codes.

Question 19

Unicode

Answer 19

A character set that represents all the languages of the world (The first 128 characters are the same as the ASCII code)

Question 20

Sampling Resolution

Answer 20

The number of bits used to represent sound amplitude in a digital sound recording.

Question 21

Bit depth

Answer 21

The number of bits used to represent the smallest unit in a sound file.

Question 22

Sampling rate

Answer 22

Is the number of samples taken per seconds

Question 23

Bitmap images

Answer 23

An Image made up of pixels.

Question 24

Color depth

Answer 24

The number of bits used to represent the colors of a pixel.

Question 25

Pixel

Answer 25

Derived from the word “picture element”, This is the smallest element used to make up an image on a display.

Question 26

Image resolution

Answer 26

The number of pixels in the X-Y direction of an image. (Example 4096x3192)

Question 27

Pixelated (image)

Answer 27

This is the result of zooming into a bitmap image, on zooming out the pixel density becomes so diminished to such a degree that the actual pixels themselves can be seen.

Question 28

Pixel density

Answer 28

The number of pixels per square inch

Question 29

Compression

Answer 29

The reduction of the size of a file by removing repeated and redundant pieces of data.

Question 30

Bandwidth

Answer 30

The maximum rate of transfer of data across the internet. Measured in kilobits per second (kbps) or megabit per second (Mbps)

Question 31

Lossy (file compression)

Answer 31

A file compression method in which parts of the original files cannot be recovered during the decompression process, for example, JPEG, mp3

Question 32

Lossless (file compression)

Answer 32

A file compression method that allows the original file to be fully restored during the decompression process, for example, Run- Length Encoding (RLE).

Question 33

Audio compression

Answer 33

A method of reducing the size of a sound file by using perceptual music shaping.

Question 34

MP3

Answer 34

A lossy file compression method for music files

Question 35

MP4

Answer 35

A lossy file compression method for multimedia files

Question 36

JPEG

Answer 36

From Joint Photographic Expert Group: A form of lossy file compression used with image files that rely on the inability of the human eye to distinguish between certain color changes and hues.

Question 37

Run length Encoding (RLE)

Answer 37

A lossless file compression technique used to reduce the size of text and photo files in particular.