Basic Components ,Types of Computers
What is a computer?
A computer is an electronic device that accepts data as input, processes it according to given instructions, stores the data, and produces meaningful output.
Name the primary hardware components of a computer.
Primary hardware components of a computer:
Input Devices – e.g., Keyboard, Mouse, Scanner
Output Devices – e.g., Monitor, Printer, Speakers
Central Processing Unit (CPU) – e.g., ALU, Control Unit
Primary Memory (RAM, Cache) – e.g., Volatile storage for active tasks
Secondary Storage (Hard Disk, SSD) – e.g., Permanent data storage
Differences between Primary and secondary memory with eg.
Primary Memory: Temporary, fast, lost when power is off. Eg: RAM, Cache
Secondary Memory: Permanent, slower, retains data without power. Eg: HDD, SSD
Define data scanning input devices.
Scanning input devices are hardware tools that capture physical data or images and convert them into digital form for the computer to process.
"This device displays text and images on a screen for users to view. Name it."
VDU means
Monitor
Visual display unit
Name the computer component called the brain.
List its two internal parts.
Explain one function of each part.
Brain of the computer: CPU (Central Processing Unit)
Two internal parts:
ALU (Arithmetic Logic Unit) – Performs arithmetic calculations and logical comparisons.
Control Unit (CU) – Directs and coordinates all operations of the computer.
Identify the device responsible for performing calculations.
What kind of operations can it do?
Device responsible for calculations: ALU (Arithmetic Logic Unit) of the CPU
Arithmetic operations: Addition, Subtraction, Multiplication, Division
Logical operations: AND, OR, NOT, XOR comparisons
Relational operations: Greater than, Less than, Equal to
Explain the main function of RAM and ROM.
RAM: Temporarily stores data and instructions while programs are running, allowing the CPU fast access.
ROM: Permanently stores essential instructions like the boot program (BIOS) that the computer needs to start.
Explain how a barcode scanner works.
Barcode scanner: Uses a laser or LED to read black and white bars, converting them into digital data.
"This device produces a physical copy of digital documents using ink or toner. Name it and give one common type."
any 2 types
Printer
Inkjet, Laser printer, 3d printer
Identify the memory that is volatile.
Explain what happens to data when power is off.
Compare it with one non-volatile memory.
Volatile memory: RAM (Random Access Memory)
When power is off:
All data stored in RAM is lost immediately because it needs continuous power to retain information.
Comparison with non-volatile memory (ROM):
RAM: Volatile, temporary, used for current tasks and running programs.
ROM: Non-volatile, permanent, stores essential instructions and retains data even when power is off.
Name the two main parts of the CPU.
ALU (Arithmetic Logic Unit) – Performs arithmetic calculations and logical operations.
Control Unit (CU) – Directs the flow of data and instructions between CPU, memory, and I/O devices.
Explain the differences between SRAM and DRAM in terms of speed, cost, and usage.
SRAM: Very fast, expensive, volatile, does not need refreshing, used as CPU cache (L1/L2/L3) and small embedded memory in devices.
DRAM: Slower than SRAM, cheaper, volatile, requires periodic refreshing, used as main system memory in desktops, laptops, and servers.
List three common applications of barcode, QR code scanners and RFID scanners.
Barcode/QR code scanners: Supermarket billing, inventory management, ticket verification.
RFID scanners: Access control, supply chain tracking.
●Step 1: Electron guns emit electrons.
●Step 2: Electrons pass through focusing and deflection systems.
●Step 3: Deflected beams hit the phosphor-coated screen.
●Step 4: Phosphor glows to form images.
●Step 5: Process repeats rapidly to refresh the image.
Which unit controls the execution of instructions?
How does it manage communication between memory and I/O devices?
Unit that controls execution of instructions: Control Unit (CU)
The CU sends control signals to control and coordinate different devices operations in the correct order.
WHat are the CPU performance metrics?
CPU Performance Metrics: Measurements used to evaluate how efficiently a CPU executes tasks.
Clock speed
Number of Core
Cache size
Manufacturing process in terms of size in nano meter
Primary Memory – RAM vs ROM
Volatility Function Speed Cost
| Feature | RAM | ROM |
|---|---|---|
| Volatility | Volatile – loses data when power is off | Non-volatile – retains data without power |
| Function | Stores data and programs currently in use | Stores firmware or permanent instructions |
| Speed | Fast | Slower compared to RAM |
| Cost | More expensive per MB | Cheaper per MB |
| Example | DDR4 RAM in computers | BIOS ROM in motherboards |
Explain how an RFID card communicates with a reader.
Give one application where this principle is commonly used.
The RFID reader emits radio waves that power the RFID tag in the card.
The RFID tag stores data and uses its antenna to transmit the data back to the reader.
Access control in offices or public transport cards.
This type of output device converts digital audio signals into sound waves that can be heard by humans. Explain its working principle, describe at least three types, and mention typical applications and advantages of each."
Audio Output Deviceis a device that converts digital or analog audio signals from a computer into audible sound.
Working Principle:
Electrical signals from the computer are sent to a transducer (speaker cone or diaphragm), which vibrates to produce sound waves that propagate through the air.
1. Trace the complete path of data from input to output.
2. Identify the role of CPU, memory, and output in this path.
3. Explain what would fail if primary memory were removed.
Path of data (Input → Output):
Input Device → Primary Memory (RAM) → CPU → Primary Memory → Output Device
Role of each component:
CPU: Processes data and executes instructions.
Memory (RAM): Temporarily stores data and instructions while processing.
Output Unit: Presents processed information in usable form (screen, printer, speaker).
If primary memory is removed:
The CPU cannot access instructions or data, so processing stops and no output is produced.
Steps in executing an instruction by the CPU:
Fetch: The CPU retrieves the instruction from memory.
Decode: The Control Unit interprets the instruction to determine the required action.
Execute: The ALU performs the arithmetic or logical operation specified by the instruction.
Store/Write Back: The result of the operation is stored in memory or sent to an output device.
Types of ROM and Their Features:
PROM (Programmable ROM): Can be programmed once after manufacturing. Data is permanent after programming.
EPROM (Erasable Programmable ROM): Can be erased using UV light and reprogrammed multiple times.
EEPROM (Electrically Erasable Programmable ROM): Can be erased and reprogrammed electrically without removing from the system.
Mask ROM: Pre-programmed during manufacturing and cannot be modified.
Working principle of Fingerprint scanner?
●Data Capture: A sensor collects biometric data (e.g., fingerprint, iris scan, facial features).
●Feature Extraction: The system extracts unique features from the biometric sample (e.g., minutiae points in fingerprints).
●Template Creation: A digital template is created and stored in the database for future comparisons.
●Matching and Verification: When the user provides a new sample, the system compares it with the stored template to verify identity.
"This output device displays enlarged visual content on a screen for audiences. Explain its working principle and describe at least three different types of this device, including their typical applications."
Projector is the device that projects images, videos, or presentations onto a larger surface for group viewing.
Working Principle:
●Light is passed through the LCD panels.
●Each pixel of the LCD panel adjusts the light intensity, forming the image.
●The combined light from all three panels is projected to create full-color images.