Chapter 1: Data Representation

fifty Q&A flashcards covering binary, decimal, hex, ASCII/Unicode, image and sound representation, storage, and data compression as per the lecture notes.

What is the language that computers understand?

Binary.

Which two digits are used in binary numbers?

0 and 1.

Binary numbers are used to represent what in computers?

Characters (letters, numbers, symbols) and data.

What base is the Denary (decimal) number system?

Base 10.

What digits does the decimal system use?

0 through 9.

Provide an example of a decimal number from the notes.

521 (also 102 or 6978 were given as examples).

What base is the Binary Number System?

Base 2.

Provide an example of a binary number from the notes.

0010100011001011.

In an 8-bit arrangement, what are the weights from the most significant bit to the least significant bit?

128, 64, 32, 16, 8, 4, 2, 1.

What is a nibble?

4 bits.

What is a byte?

8 bits.

What is the base of the hexadecimal number system?

16.

What digits does hexadecimal use?

0-9 and A-F.

Why are hexadecimal numbers used in computing?

To spot errors easily, to read/write memory addresses, colors in HTML, MAC addresses, assembly instructions, and for easier debugging.

In HTML, how are hexadecimal numbers commonly used?

To define colors.

What does ASCII stand for?

American Standard Code for Information Interchange.

How many bits per character does ASCII use?

7 bits.

How many characters are defined by ASCII?

128 characters.

What is Unicode?

An encoding that allows many more characters than ASCII, using multi-bit codes (16-bit in the basic form).

How are ASCII and Unicode related?

ASCII is a subset of Unicode; Unicode extends ASCII to support more characters.

What is the purpose of a band-limiting filter in sound processing?

To remove high-frequency components before converting analog sound to digital.

What does ADC stand for?

Analog to Digital Converter.

What are the two components mentioned for sound encoding?

A sound encoder and a band-limiting filter.

What are the two factors to consider when coding sound?

Sampling rate and sampling resolution.

What is sampling rate?

The number of samples taken per second (Hz).

What is sampling resolution?

The number of bits used per sample.

What happens if you increase both sampling rate and sampling resolution?

Better digitised sound with less quantisation error, but larger file size.

What is a pixel?

The smallest element of an image, defined by its position and colour.

What is an image's resolution?

The number of pixels in the image.

What is colour depth?

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

What is a bitmap?

An image represented as a grid of pixels.

How does increasing resolution or colour depth affect file size?

It increases the file size.

What does KiB stand for and what is its value in bytes?

Kibibyte; 1024 bytes.

What is a mebibyte (MiB)?

1024 KiB; 1,048,576 bytes.

What is a gibibyte (GiB)?

1024 MiB; 1,073,741,824 bytes.

What is a tebibyte (TiB)?

1024 GiB.

What is a pebibyte (PiB)?

1024 TiB.

What is an exbibyte (EiB)?

1024 PiB.

What is the decimal kilobyte (KB) value?

1000 bytes.

Why is data compression used?

To reduce file size for less bandwidth, storage, and faster data transfer.

What are the two types of data compression?

Lossless and Lossy.

What is lossless compression?

A compression method where the original file can be exactly reconstructed after decompression.

What is lossy compression?

A compression method where some information is lost and the exact original cannot be recovered after decompression.

What is Run-Length Encoding (RLE)?

A lossless compression technique that encodes runs of repeated patterns as a symbol and count.

Name some formats associated with compression mentioned in the notes.

JPEG, GIF, MP3, MP4.

What is the difference between a bitmap image and a vector image?

bitmap as a series of pixels; a bitmap is a grid of pixels.

What is the relationship between resolution and file size in images?

Higher resolution generally increases file size.

What is the role of color depth in image files?

It determines how many bits are used to represent the color of each pixel; more depth increases quality and size.

What is the approximate file size impact of higher color depth and resolution?

Both typically increase file size.

What is the primary use of hexadecimal numbers in computing?

To represent memory addresses, color values, and instruction encoding in a compact form.

What is the main advantage of hexadecimal over binary for readability?

Hexadecimal is more compact and easier to read than long binary sequences.

What is the purpose of using ASCII before Unicode?

ASCII provides a simple 7-bit encoding for basic English characters and is a subset of Unicode.

What is the commonly cited base used to describe data sizes in binary prefixes (KiB, MiB, etc.)?

Base-2 prefixes (kibi-, mebi-, gibi-, tebi-, pebi-, exbi-), where 1 KiB = 1024 bytes.

What is the typical use of hexadecimal in debugging and memory inspection?

To identify values and memory addresses more easily.

What is the standard example of a numeric binary representation given in the notes?

0010100011001011.

What happens when you reduce sampling rate or color depth in media files?

File size decreases but quality may degrade.

Which file types listed are commonly associated with lossy compression in the notes?

JPEG (images), MP3 (audio), MP4 (video).

Which file types listed are commonly associated with lossless compression or uncompressed formats?

BMP (images) and WAV (audio) are often associated with lossless or uncompressed formats.

What is the effect of increasing the number of bits per sample in audio?

Improved accuracy of the digitised sound, less quantisation error, but larger file size.

What is the effect of increasing the sampling rate in audio?

Improved representation of the waveform, but larger file size.

What is the common term for converting analogue signals to digital numbers?

Analog-to-Digital Conversion (ADC).