📘 Std 4 – Computer
💾 Chapter 1: Memory and Storage
🔹 Computer Memory
Computer memory is the storage area where data and instructions are stored. It includes short-term and long-term storage.
🔹 Data Storage Units
- Bit (0 or 1)
- 1 Byte = 8 bits
- 1 KB = 1024 Bytes
- 1 MB = 1024 KB
- 1 GB = 1024 MB
- 1 TB = 1024 GB
🔹 Types of Memory
- Primary Memory: RAM, ROM
- Secondary Memory: Hard Disk, Pen Drive, CD, DVD, etc.
🔹 RAM
RAM stores data temporarily. Data is lost when computer is turned off. It is called volatile memory.
🔹 ROM
ROM stores permanent instructions. Data is not lost when power is off. It is non-volatile memory.
🔹 Secondary Storage Devices
- Hard Disk
- SSD
- CD / DVD / Blu-ray
- Pen Drive
- Memory Card
- Cloud Storage
🔹 RAM vs ROM
| RAM | ROM |
| Temporary | Permanent |
| Data lost | Data safe |
| Volatile | Non-volatile |
✏️ A. Fill in the blanks
- Data is measured in Bytes.
- RAM and ROM are types of internal memory.
- Pen drive is also called Flash Drive.
- A CD can store up to 700 MB and is 4.7 inches.
✔️ B. True or False
- RAM stands for Random Access Memory – True
- SSD gives high performance – True
- Flash drive is small and rewritable – True
- 1 MB = 1024 GB – False
🔘 C. Multiple Choice Questions
- 0 and 1 are called Binary
- Temporary memory is RAM
- Blu-ray uses Blue-violet Laser
- Data lost when off → RAM
🔗 D. Match the Following
- ROM → Internal Memory
- DVD → 4.7 GB
- Blu-ray Disc → 50 GB
- Flash Drive → Plug-and-Play Device
🧠 E. Competency Questions
- Use Pen Drive
- Use External Hard Disk
📝 F. Answer the Following
- Primary Memory: Built-in memory (RAM & ROM).
- Hard Disk: Stores large data permanently.
- Cloud Storage Benefits: Access anywhere, backup safe.
- Memory Card: Used in mobiles for storage.
- RAM vs ROM: RAM temporary, ROM permanent.