ICAS Year 7 Digital Technologies – File Sizes & Compression Key Terms

Bit

The smallest unit of digital data representing 0 or 1

Byte

A group of 8 bits used to store data

Kilobyte (KB)

Approximately 1,024 bytes of data

Megabyte (MB)

About 1,024 kilobytes of data

File Size

The amount of digital data in a file, measured in bytes or multiples

Lossless Compression

Reducing file size without losing any data or quality

Lossy Compression

Reducing file size by removing some data, which may lower quality

.jpg

A compressed image file format that uses lossy compression

.bmp

An uncompressed image file format that uses more storage space

Resize Image

Changing an image’s dimensions to reduce file size without losing quality

Compression

The process of making a file smaller to save space or speed transfer

Text File

A small file type containing only text, usually with .txt extension

Audio File

A file storing sound data; formats include .mp3 (compressed) and .wav (uncompressed)

Video File

A file storing moving images and sound, often large in size, e.g., .mp4

Why Compress Files

To save storage space and make files easier and faster to send or upload

File Extension

Letters after the dot in a file name that shows its type, e.g., .jpg, .mp3

Bytes to Bits

1 byte equals 8 bits

Email Attachment Limit

Files too big need to be compressed before sending by email