Conduct routine Maintenance service of computer system and peripherals

  1. What is a Computer System?

A computer system is a group of electronic parts (hardware) and programs (software) that work together to receive data, process it, and produce results.

When you type a letter in Microsoft Word and print it:

• Keyboard – sends data (input)
• Computer – processes data
• Monitor & Printer – show results (output)

 

 2. Main Parts of a Computer System

A computer system has three main parts:

a) Hardware

The physical parts you can see and touch.

Examples:

• Input devices – keyboard, mouse, scanner
• Output devices – monitor, printer, speakers
• Storage devices – hard disk, pen drive
• System unit – CPU, motherboard, RAM, power supply

 

 b) Software

The programs that tell the computer what to do.

Type	Function	Example
System Software	Controls hardware	Windows, Linux, macOS
Application Software	Helps user do work	MS Word, Excel, Photoshop
Utility Software	Maintenance tools	Antivirus, Disk cleanup

 

 c) Peopleware

The users who use the computer – teachers, students, operators, technicians.

 

 3. Internal Hardware Components

Inside the system unit (CPU cabinet), you’ll find:

Component	Function
Motherboard	Main circuit board connecting all parts
Processor (CPU)	Brain of the computer – processes data
RAM (Memory)	Temporary memory for running programs
ROM (Read Only Memory)	Stores system startup instructions
Hard Disk / SSD	Permanent storage of files and programs
Power Supply Unit (PSU)	Converts power from AC to DC
Cooling Fan	Keeps system cool

 

 4. Input Devices

Input devices are used to enter data into the computer.

Device	Function
Keyboard	Type letters, numbers, commands
Mouse	Move pointer and click options
Scanner	Convert paper documents into digital form
Microphone	Record sound
Webcam	Capture live video
Barcode Reader	Read product codes
Joystick	Control games or simulations

 

 5. Output Devices

Output devices show or produce the processed information.

Device	Function
Monitor	Display images and text
Printer	Print documents on paper
Speaker	Play sound or music
Projector	Show display on a big screen
Plotter	Draw large diagrams (engineering drawings)

 6. Storage Devices

These devices store data and programs permanently or temporarily.

Type	Example	Description
Primary Storage	RAM, ROM	Used while computer is working
Secondary Storage	Hard Disk, SSD	Stores data permanently
Removable Storage	Pen Drive, CD, DVD	Portable storage
Cloud Storage	Google Drive	Internet-based storage

 

 7. Peripherals

Peripherals are external devices connected to the computer to expand its functions.

Types of Peripherals:

1. Input peripherals: Keyboard, Mouse, Scanner
2. Output peripherals: Printer, Monitor, Speaker
3. Storage peripherals: Pen drive, External hard disk
4. Communication peripherals: Modem, Router, Network Card

 8. Ports and Connectors

Ports allow peripherals to connect to the computer.

Port	Use	Example Device
USB Port	Universal connection	Pen drive, mouse
HDMI Port	Display output	Monitor, Projector
Ethernet Port	Network connection	LAN cable
Audio Port	Sound input/output	Headphones, mic
VGA Port	Old display connector	Monitor

 

 9. Basic Computer System Functions

A computer performs four main functions:

1. Input: Accepts data → (keyboard, mouse)
2. Process: Works on data → (CPU)
3. Output: Displays result → (monitor, printer)
4. Storage: Saves data → (hard disk, pen drive)

 

 

 10. Maintenance and Safety

To keep the computer and peripherals working properly:

• Keep computer clean and dust-free
• Avoid liquid spills
• Use antivirus software
• Shut down properly before turning off power
• Use UPS to protect from power failure
• Handle cables gently and label them

 

 11. Troubleshooting Common Problems

Problem	Cause	Solution
No power	Loose cable	Check power cable
No display	Monitor off / cable loose	Reconnect monitor
Keyboard not working	Port damaged	Try another port
Slow performance	Too many programs	Close unused programs
Printer not printing	Paper jam / no ink	Clear jam, refill ink

 

 12. Advantages of Computer Systems

·       Fast and accurate

·       Can store large data

·       Easy communication (email, chat)

·        Improves learning and productivity

·       Easy to share information

 

 13. Disadvantages

•     Expensive hardware/software
•     Data loss possible (without backup)
•    Virus or malware attacks
•    Requires electricity and maintenance

1. What is a Computer Network?

A computer network is a group of two or more computers connected together to share data, files, printers, and the internet.

• In an office → all computers are connected to share a printer and internet.
• In a school → teachers and students use the same Wi-Fi to access online materials.

2. Purpose of a Network

Purpose	Example
Share files	Students share notes or documents
Share printers	All staff use one network printer
Share internet	Wi-Fi connection for many users
Communication	Email, Chat, Video calls
Central management	Data stored in one server

3. Components of a Computer Network

a) Computers (Nodes)

Every device connected to the network (PC, laptop, phone) is called a node.

 b) Network Devices

Hardware used to connect and control the network:

• Switch – Connects many computers in a LAN
• Router – Connects networks and provides internet
• Modem – Connects to ISP (Internet Service Provider)
• Access Point – Provides wireless (Wi-Fi) access
• NIC (Network Interface Card) – Connects PC to the network

 c) Transmission Media (Cables/Wireless)

• UTP Cable (LAN cable) – Most common in LAN
• Fiber Optic Cable – High speed and long distance
• Wireless (Wi-Fi) – No cables; uses radio signals

 d) Network Software

Programs used for communication and control:

• Operating System: Windows Server, Linux
• Protocols: TCP/IP (rules for data transfer)
• Network Tools: Ping, IPconfig, File sharing, etc.

4. Types of Computer Networks

Type	Description	Example
LAN (Local Area Network)	Covers small area like office, lab	School, company
MAN (Metropolitan Area Network)	Covers city or large campus	University, city network
WAN (Wide Area Network)	Covers large distances	Internet
PAN (Personal Area Network)	Small personal connection	Bluetooth, Hotspot

5. Network Topologies (Connection Structures)

Topology means the way computers are connected in a network.

Type	Description
Bus	All devices connected to a single cable
Star	All devices connected to a central switch
Ring	Devices connected in a circle
Mesh	Every device connected to all others
Hybrid	Combination of two or more topologies

6. Network Devices (Detailed Explanation)

Device	Function	Example
Switch	Connects many computers in a LAN	Used in labs
Router	Connects networks and shares internet	Wi-Fi Router
Hub	Connects devices but sends data to all	Used in small networks
Modem	Connects to Internet provider	SLT Router
Access Point	Provides wireless connection	Wi-Fi point
Bridge	Connects two LANs	Network expansion
Gateway	Connects two different networks	Internet link

7. Types of Network Connections

Type	Description
Wired Network	Uses cables (UTP, Fiber) for connection
Wireless Network	Uses radio waves (Wi-Fi, Bluetooth)

Example:

• LAN with cables → Wired
• Wi-Fi or Mobile Hotspot → Wireless

8. IP Address (Internet Protocol Address)

An IP address is a unique number given to each device in a network.

Example:

192.168.1.10

Types:

• IPv4 – 32-bit, Example: 192.168.1.1
• IPv6 – 128-bit, Example: 2001:db8::1

9. Network Protocols

Protocols are rules for communication between devices.

Protocol	Purpose
TCP/IP	Main protocol for internet
HTTP/HTTPS	Used for websites
FTP	Transfer files
SMTP/POP3	Send and receive emails
DNS	Converts website names to IP addresses

10. Network Sharing

In a network, users can share:

• Files and folders
• Printers and scanners
• Internet connection
• Databases and applications

11. Advantages of Networking

·       Share resources easily

·       Save cost (one printer for all)

·       Fast communication

·       Centralized data management

·       Easy to backup and update

12. Disadvantages of Networking

·       Virus can spread quickly

·       Hacking or data theft possible

·       Setup cost can be high

·       If server fails, work stops

13. Basic Network Troubleshooting

Problem	Possible Cause	Solution
No internet	Loose cable / router off	Check cables and router
IP conflict	Two devices with same IP	Change IP
Slow network	Too many users	Limit usage
Wi-Fi not connecting	Wrong password	Reconnect
Printer not shared	Network error	Reconnect printer

14. Network Safety Tips

• Use strong passwords
• Install firewall and antivirus
• Do regular backups
• Allow access only for authorized users
• Update system software regularly