Units - Data Storage

Question 1

State the Number of Bytes for
Bit
Nibble
Byte
Kilobyte
Megabyte
Gigabyte
Terabyte
Petabyte

Answer 1

Bit - 1/8
Nibble - 1/2
Byte - 1
Kilobyte - 1000
Megabyte - 1000000
Gigabyte - 1000000000
Terabyte - 1000000000000
Petabyte - 1000000000000000

Question 2

What are the steps to convert Denary numbers to binary number

Answer 2

arrange the column headings of the powers of 2. Minus away the largest possible number from the denary number. Continue doing this until complete

Question 3

What are the steps to convert binary numbers to denary numbers

Answer 3

Place the binary number beneath the column headings of each sector. Then multiply the numbers together. Add up the numbers. There is your denary number

Question 4

What are the steps to add binary numbers

Answer 4

Place the numbers one below the other. Make sure they both are equally up to each other on the right side. Then do column addition. A 1 + 1 = 0 , 1 + 0 = 1 , 0 + 0 =0. And when you add a 1 + 1 you take a 1 to the next column.

Question 5

What is binary shift and how does it work?

Answer 5

Binary shift is when you multiply or divide a number by 2. Shifting the numbers to the right by one column is dividing by 2 and shifting the numbers to the left by one column is multiplying by 2.

Question 6

What are the steps to convert denary numbers into Hexadecimal numbers.

Answer 6

First divide the denary number by 16. Then find the remainder left over. Convert the numbers to their Hex values.

Question 7

What are the steps to convert binary to hex

Answer 7

Separate the 8-bit binary into 2 4-bit binary numbers. Then find the denary value of the hex piece. Then convert the denary values to their hex values.

Question 8

What are the steps to convert hex numbers into binary

Answer 8

Split the two hex numbers into seperate numbers. Find the binary values of each part. Join the two binary values together to get your full number

Question 9

What is a character set

Answer 9

A character set us a logically ordered set of all the characters that can be encoded using a given number of bits.

Question 10

How are characters represented in binary

Answer 10

Depending on how many bits are used to code the characters the binary code is made for each and every character possible in the character set.

Question 11

What is ASCII

Answer 11

American Standard Code for Information Interchange is a character set which uses all of the possible characters on a keyboard. It is made of 7 bits which means there are 128 possibilities.
The extended ASCII character set uses 8bits which allows for special symbols and some foreign language characters.

Question 12

What is Unicode

Answer 12

Unicode is a new method of representing characters for all of the languages in the world, including chinese, japanese, arabic, greek.

Question 13

How are images represented

Answer 13

When images are saved on a computer they are saved as large groups of very small pixels. The size of an image is measured by the width in pixels by height in pixels.
The resolution of an image is measured in Pixels per Inch or PPI

Question 14

What are the effects on image size and quality when changing colour depth and resolution

Answer 14

The more colours in a picture (colour depth) the higher the file size of the image.
the greater the resolution (number of pixels per inch) the larger the file size as the computer has to store more pixels.

Question 15

What is Metadata

Answer 15

Metadata is ‘data about data’.
When you save a file you save the data about the:
- the type of file
- time and date of creation
- creator or author of the data
- file size
- colour depth
- image resolution
- dimension of the image

Question 16

How can sound be sampled and stored in digital form

Answer 16

Sound waves are analogue so they are converted to a digital format to be stored.
They use an Analogue-to-Digital Converter (ADC)
Method:
Analogue sound is received by the microphone, which is converted to an electrical analogue signal. Then the signals amplitude is measured at regular intervals (sampling).
The values are stored as binary numbers.

Question 17

What are the effects of sample rate, duration and bit depth on the playback quality and the size of a sound file

Answer 17

The higher the sample rate (number of samples/second) the better the quality of the playback and the higher the file size
The higher the resolution (number of bits/sample) the better the quality of the playback and the higher the file size
The higher the sample size the higher the file size. Does not affect quality.

Question 18

What is lossy compression

Answer 18

A method when files are compressed by removing some of the details.
E.g. jpg,mp3,mpg

Question 19

What is lossless compression

Answer 19

A method when files are compressed by no data is lost - an essential factor for text and data files.
E.g. png,gif,zip,pdf