Study Notes
Data storage involves understanding how data is represented and measured in computer systems, while file compression reduces the size of files for efficient storage and transmission.
- Bit — the basic unit of computer memory processing. Example: A bit can hold either a 1 or a 0.
- Byte — the smallest unit of memory, consisting of 8 bits. Example: 1 byte = 8 bits.
- Kilobyte (KB), Megabyte (MB), Gigabyte (GB) — units of data measurement. Example: 1 KB = 1024 bytes.
- Lossy Compression — a method where some data is lost, and the process is irreversible. Example: JPEG, MP3.
- Lossless Compression — a method that preserves all original data without loss. Example: PNG, GIF.
- Run-Length Encoding (RLE) — a lossless compression algorithm that encodes repeated data. Example: 100000001000111111100011110000111 becomes 1701307130414031.
Exam Tips
Key Definitions to Remember
- Bit
- Byte
- Lossy Compression
- Lossless Compression
- Run-Length Encoding (RLE)
Common Confusions
- Confusing bits and bytes
- Thinking lossy compression can be reversed
Typical Exam Questions
- What is a bit? A bit is the basic unit of computer memory processing, holding either a 1 or a 0.
- How does lossy compression differ from lossless compression? Lossy compression loses some data and is irreversible, while lossless compression retains all data.
- What is Run-Length Encoding? RLE is a lossless compression technique that encodes repeated data into shorter lengths.
What Examiners Usually Test
- Understanding of data measurement units
- Differences between lossy and lossless compression
- Ability to calculate file sizes using given formulas