Memory & Storage
A computer needs two things to handle your files: Memory (for working right now) and Storage (for keeping data long term). They are different — just like your work desk and your school bag.
RAM – Random Access Memory
RAM is the computer's working memory. When you open a game or a document, it loads into RAM. RAM is very fast but it forgets everything when you switch off the computer.
ROM – Read Only Memory
ROM is built into the computer. It stores the startup instructions — the steps the computer follows each time it turns on. You cannot change ROM, and it keeps its data even when the power is off.
RAM = Desk (fast but temporary) | Storage = Bag (slower but permanent)
Types of Storage
Hard Disk Drive (HDD)
A hard disk is a spinning disk inside the CPU box. It stores large amounts of data cheaply. Most computers come with a hard disk of 500 GB or more.
SSD – Solid State Drive
An SSD stores data on chips with no moving parts. It works much faster than a hard disk and is quieter. New laptops often use SSDs.
USB Pen Drive (Flash Drive)
A pen drive plugs into the USB port. You carry it in your pocket to move files between computers. A common pen drive holds 8 GB to 128 GB.
CD and DVD
CDs and DVDs are flat round discs. A CD holds about 700 MB. A DVD holds about 4.7 GB. You use them to watch movies or install software.
Units of Storage
| Unit | Short Form | Size |
|---|---|---|
| Kilobyte | KB | 1,024 Bytes |
| Megabyte | MB | 1,024 KB |
| Gigabyte | GB | 1,024 MB |
| Terabyte | TB | 1,024 GB |
✏️ Exercise
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