Activity -1: Exploring Computer Memory - VIII

Activity: Exploring Computer Memory

Welcome to this guided activity! By the end of this exercise, you will have a solid understanding of how a computer's memory works, including its types, units of measurement, and key characteristics.

Step 1: Understand Memory Basics

• A computer's memory is a physical device for storing information either **temporarily or permanently**.
• All data is converted into the **binary number system** (0s and 1s) before being stored.
• It's where data and programs are stored **before being processed** and where results are stored before being sent as output.

Step 2: Learn the Units of Measurement

Just as we use units like kilograms and grams to measure weight, computer memory is measured in specific units based on binary digits.

• **Bit:** The smallest unit, a binary digit (**0 or 1**).
• **1 Nibble:** **4 Bits**
• **1 Byte (B):** **8 Bits**
• **1 Kilobyte (KB):** **1024 Bytes**
• **1 Megabyte (MB):** **1024 Kilobytes**
• **1 Gigabyte (GB):** **1024 Megabytes**
• **1 Terabyte (TB):** **1024 Gigabytes**
• **1 Petabyte (PB):** **1024 Terabytes**

Step 3: Discover Primary Memory

• It is also known as **volatile memory**, meaning data is **lost when the power is turned off**.
• It provides the main working space for the computer and is generally made of semiconductor devices.

RAM (Random Access Memory)

• **Function:** Stores data, programs, and program results that are **currently in use** for quick access by the CPU.
• **Characteristic:** It is much faster than secondary storage. Its contents are **volatile**.
• **Types:**
  • **DRAM (Dynamic RAM):** Needs to be periodically refreshed to retain data.
  • **SRAM (Static RAM):** Faster than DRAM and more expensive; used for the computer's **cache memory**.

ROM (Read Only Memory)

• **Function:** Permanently stores data that can only be **read**, not easily changed.
• **Characteristic:** It is **non-volatile**, meaning the data is **not lost when power is turned off**.
• **Types:**
  • **PROM:** Data can be written only **once**.
  • **EPROM:** Can be erased by exposing it to strong **ultraviolet rays**.
  • **EEPROM:** Can be erased and rewritten with the help of **electricity**.

Step 4: Explore Secondary Memory

• Used to store large amounts of data **permanently**.
• It is **non-volatile** and is not directly accessible by the CPU.
• Access speed is much **slower** than primary memory (milliseconds vs. nanoseconds).

Examples of Secondary Storage Devices

• **Magnetic Tape:** A **sequential** storage medium that is slow but highly reliable for backups.
• **Magnetic Disk:** Stores data using a magnetization process (e.g., **Hard Disk Drive (HDD)**). Hard disks have a very high storage capacity.
• **Optical Disk:** Uses optical technology for data storage and retrieval.
  • **CD (Compact Disc):** Can store up to **650 MB** of information.
  • **DVD (Digitally Versatile Disk):** Provides a higher storage capacity of **4.7 GB**.
• **Flash Memory:** Modern portable storage solutions like **USB flash drives**.