Study Notes
Data storage in computers is categorized into Primary Memory and Secondary Storage. Primary memory includes RAM and ROM, where RAM is volatile and used for temporary data storage, while ROM is non-volatile and stores permanent data. Secondary storage includes devices like HDDs, SSDs, and optical discs, which provide permanent data storage and are not directly accessed by the CPU.
- Primary Memory — the main storage used by the computer for temporary data. Example: RAM and ROM
- RAM (Random Access Memory) — volatile memory used to store data temporarily while the computer is on. Example: DRAM and SRAM
- ROM (Read Only Memory) — non-volatile memory used to store permanent data that does not change. Example: BIOS instructions
- Secondary Storage — permanent storage not directly accessed by the CPU. Example: HDDs, SSDs, CDs
- HDD (Hard Disk Drive) — uses magnetic platters to store data sequentially. Example: Personal files and applications
- SSD (Solid State Drive) — uses transistors for faster data access and durability. Example: USB flash drives
- Optical Storage — uses laser light to read and write data. Example: CDs, DVDs, Blu-Ray Discs
- Virtual Memory — uses HDD space to extend RAM capacity temporarily. Example: Running large applications
- Disk Thrashing — excessive swapping between RAM and virtual memory causing slow performance. Example: System slowdown during high memory usage
Exam Tips
Key Definitions to Remember
- Primary Memory: The main storage used by the computer for temporary data.
- RAM: Volatile memory used to store data temporarily while the computer is on.
- ROM: Non-volatile memory used to store permanent data that does not change.
- Secondary Storage: Permanent storage not directly accessed by the CPU.
Common Confusions
- Confusing RAM with ROM: Remember, RAM is volatile and temporary, while ROM is non-volatile and permanent.
- Mixing up HDD and SSD: HDDs use magnetic platters, while SSDs use transistors.
Typical Exam Questions
- What is the difference between RAM and ROM? RAM is volatile and temporary, while ROM is non-volatile and permanent.
- How does an SSD differ from an HDD? SSDs are faster and more durable than HDDs as they have no moving parts.
- What is virtual memory used for? It extends RAM capacity by using HDD space temporarily.
What Examiners Usually Test
- Understanding of different types of memory and storage.
- Differences between primary and secondary storage.
- Characteristics and uses of RAM, ROM, HDDs, and SSDs.