Computer Science Notes: Storage, Binary, and Data Representation

Vocabulary flashcards covering binary numbers, data units, storage types, color representations, and sound data from the lecture notes.

Bit

The smallest unit of data in computing; a single 0 or 1.

Byte

Eight bits; the basic memory unit (notes describe 8 bits = 1 byte).

Nibble

A group of four bits.

Binary

Base-2 number system using digits 0 and 1, with each position weighted by powers of 2.

Kilobyte (KB)

Unit of data equal to 1,000 bytes (decimal) or 1,024 bytes (binary) depending on convention.

Megabyte (MB)

Unit equal to 1,000,000 bytes or 1,024 kilobytes.

Gigabyte (GB)

Unit equal to 1,000,000,000 bytes or 1,024 megabytes.

Terabyte (TB)

Unit equal to 1,000,000,000,000 bytes or 1,024 gigabytes.

Petabyte (PB)

Unit equal to 1,000,000,000,000,000 bytes or 1,024 terabytes.

Hexadecimal

Base-16 number system using digits 0-9 and A-F; used for large values and color codes.

ASCII

American Standard Code for Information Interchange; originally 7-bit (128 chars); extended ASCII uses 8 bits (256 chars).

Unicode

32-bit encoding capable of representing millions of characters from many languages and symbols, including emojis.

Secondary storage

Non-volatile storage that keeps data when power is off; typically slower than primary but larger and cheaper.

Optical storage

CDs, DVDs, Blu-ray discs; data written with a laser creating pits/lands and read by light reflection.

Magnetic storage

HDDs, magnetic tapes, floppy disks; data written by magnetizing particles and read by detecting orientation.

Solid-state storage

SSDs, USB flash drives, SD cards; uses flash memory with no moving parts; fast access.

Cloud storage

Data stored on remote servers accessed over the internet; advantages: accessibility and collaboration; disadvantages: internet dependency and privacy concerns.

Pixel

The smallest element of a digital image; stores color information.

Bitmap

A digital image made up of a grid of pixels.

Colour depth

Number of bits used to store color information per pixel; higher depth means more colors.

File size (image)

File size = width × height × colour depth (bits) ÷ 8.

Resolution

Number of pixels in an image; more pixels = higher quality and larger file size.

Flash memory

Non-volatile memory used in SSDs and USB drives; stores data in transistor charge to represent 0/1; read by detecting charge state.

Write head

Magnetic component that writes data by aligning magnetic particles.

Read head

Component that reads data by sensing the orientation of magnetic particles.

Optical write

Process of burning pits and lands on an optical disc with a laser.

Optical read

Reading by shining light and detecting reflections from pits/lands on an optical disc.

Audio sample

A single amplitude measurement of a sound wave at a moment in time.

Sample rate

Number of samples taken per second (measured in Hz).

Sample resolution

Number of bits used for each audio sample.

File size (audio)

File size = sample rate × sample resolution × time × number of channels.

Hz

Hertz; unit of frequency measuring cycles per second.