The Binary Number System, The Hexadecimal Number System, Character Sets, Images, Sound, Compression

What is a bit in the binary system?

A binary digit that stores either 0 or 1

What is a nibble?

A group of 4 bits

What is a byte?

A group of 8 bits

How many numbers can a byte store?

256

How is binary addition similar to denary addition?

It uses the same column-based method

What is 1+1 in binary?

10

What is 1+1+1 in binary?

11

What happens if binary addition results in a carry at the end?

The carry is placed at the beginning, making a 9-bit answer

What happens when the sum of two bytes exceeds 255?

It causes an overflow error

How do modern CPUs handle overflow errors?

They can hold much larger numbers

What is a binary shift used for?

To multiply or divide a number by powers of two

What happens when a LEFT BINARY SHIFT occurs?

The number doubles in size

What happens when a RIGHT BINARY SHIFT occurs?

The number halves in size

What does ASCII require?

127 different codes

How many bits are used in the ASCII system?

7 bits

What does Extended ASCII use?

8 bits

Why was a new character set developed for 16-bit computers?

To accommodate other languages around the world

What is the name of the new character set for 16-bit computers?

UNICODE

How many bits does UNICODE use?

32 bits

What are bitmap images made of?

Rows of pixels

How is each pixel represented in an 8-bit image?

By a byte

How is each pixel represented in a 24-bit image?

By 3 bytes, with each byte representing a shade of red, green, or blue

Why do HD movies and images appear to have higher quality?

Because the pixels are smaller, giving more detail and reducing pixelation

What makes an image look more 'real'?

A greater range of colours

What does low colour depth mean?

Each pixel is represented by a short binary number, resulting in fewer colours

What does high colour depth mean?

Each pixel is represented by a long binary number, resulting in a larger file

How do you calculate the size of an image file?

Multiply the number of pixels by the colour depth

What is metadata in an image file?

Additional information such as the height, width, and colour depth of an image

What is analogue sound?

Sound waves that continuously vary and are of perfect quality

What is digital sound?

Sound that has been sampled at set intervals, not pure or perfect quality

What is sampling in digital sound?

Recording snippets of sound at set intervals

What is a sample in digital sound?

A measure of the amplitude of the sound wave at a specific moment in time

What does sample resolution (bit depth) refer to?

The number of bits used in each sample

How does a higher sample resolution affect sound quality?

It records more data per sample, resulting in higher quality sound

What is the formula to calculate the data of a sound file?

Sample rate per second x time x bit depth

What does metadata tell the computer in a sound file?

It tells the computer what type of file it is and how to split up and play back the binary values

Why might a file need to be reduced in size?

To require less storage space, faster download times, and faster streaming speeds

What is lossy compression?

When unrequired data is removed from a file to reduce its size

What is lossless compression?

When data is temporarily removed from a file but added back when the file is used again

How does lossy compression compare to lossless compression?

Lossy compression results in a much smaller file

What is run length encoding?

A simple form of lossless compression that looks for patterns to manipulate and remake

What is dictionary coding?

A form of lossless compression that replaces the file’s data with a reference to what the data is

What must accompany a compressed file when using dictionary coding?

The dictionary