Bits Bytes And Binary

Question 1

Kilo

Answer 1

kB
1,000

Question 2

Mega

Answer 2

MB
1,000,000

Question 3

Giga

Answer 3

GB
1,000,000,000

Question 4

Tera

Answer 4

1,000,000,000,000

Question 5

How many bits in a byte

Answer 5

8

Question 6

New prefixes

Answer 6

KIB
2X10
MIB
2X20
GIB
2X30
TIB
2X40

Question 7

Transmission errors

Answer 7

When data is transmitted, it does not always arrive in the same format that it was sent
- electrical interference
- power surges
- synchronisation issues
- wear and tear on the cable or connectors
These errors can cause bits to flip from 1s to 0s and 0s to 1s

Question 8

4 methods for error checking

Answer 8

Parity bits
Majority voting
Check digits
Checksums

Question 9

Parity bits

Answer 9

Computers use either odd or even Parity
When sending a byte of data, one bit is used as a parity bit
This bit is set to a 1 or 0 to make the total number of 1s or 0s in the Byte odd or even depending on the machine
If the wrong number of bits are on an error has occurred

Question 10

Majority voting

Answer 10

Each bit of a message is sent 3 times
If a bit value is flipped erroneously the recipient computer uses the majority rule and assumes that the 2 bits that have not changed were therefore correct

Question 11

Check digits

Answer 11

A check digit is an additional digit at the en d of a string of other numbers designed to check for mistakes in input or transmission
Printed books and other products have a unique barcode

Question 12

Check sums

Answer 12

A total sum of all the bytes in a transmission of data is calculated using an algorithm
The sum is often sent with the data
The reciveing computer recalculates the checksum based on the data it received and compared it with the checksum received or a known, expected value
If it does not much the data may have been altered or corrupted during transmission