Section 3 Chapter 14 - Bits, bytes and binary

Question 1

Bit

Answer 1

Either a 1 or a 0

Question 2

Byte

Answer 2

A set of eight bits

Question 3

Nibble

Answer 3

A set of four bits

Question 4

Kilobyte

Answer 4

1000 bytes

Question 5

Kibibyte

Answer 5

1024 bytes

Question 6

Symbol for megabyte

Answer 6

M

Question 7

Symbol for mebibyte

Answer 7

Mi

Question 8

ASCII

Answer 8

A code for representing characters. 7 bits are used to represent a total of 128 different characters.

Question 9

ASCII “0”

Answer 9

48

Question 10

ASCII “A”

Answer 10

65

Question 11

ASCII “a”

Answer 11

97

Question 12

Why ASCII cannot be used for arithmetic

Answer 12

Because the codes for the numbers characters are not equal to the numbers actual value

Question 13

How many bits in an ASCII character

Answer 13

Originally 7 but now sometimes 8

Question 14

Unicode

Answer 14

A code for representing all worldly characters

Question 15

Advantage of unicode

Answer 15

Now all languages operate under one system and there is no incompatibility. All characters are represented.

Question 16

Disadvantage of unicode

Answer 16

Each character requires 4 bytes instead of 1

Question 17

Why computers need to verify data that they recieve

Answer 17

Because bits can change during transmission due to inteference

Question 18

Parity bit

Answer 18

A bit used to check if the other transmitted bits are correct

Question 19

How parity bits work

Answer 19

They make the total number of 1s and 0s either odd or even

Question 20

Majority voting

Answer 20

Every bit is sent three times and the computer receiving decides that the majority bit is the correct one.
If there are two 1s and one 0 the receiver will interpret this as a 1

Question 21

Checksum

Answer 21

A mathematical algorithm that is applied to a packet of data. A number is generated with this algorithm and sent with the packet. The receiver then uses this same algorithm to determine the number. If the numbers don’t match then the packet must be sent again

Question 22

Check digit

Answer 22

An extra digit at the end of a series of digits used to check for mistakes in input or transmission. The digit is calculated by applying some mathematical algorithm to the packet of data it is associated with.

Question 23

How the ISBN check digit works

Answer 23

12 digits + 1 check digit
Each digit is given alternating weights of 1 and 3
These numbers are summed
The remainder when divided by 10 is taken
This number is taken away from 10
This number is the check digit

Question 24

Historical use of kilo, mega…

Answer 24

Used where kibi, mebi… should have been used

Question 25

Why unicode was introduced

Answer 25

To have a coding system that can represent all characters for every country and have different countries use compatible coding systems.

Question 26

How many bytes in a unicode character

Answer 26

2 in UTF-16

4 in UTF-32

Question 27

Disadvantage of majority voting

Answer 27

The data is sent three times