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৪৯তম স্পেশাল বিবিএি (বশক্ষা)-এর ❝বশক্ষা❞

বিষয়বিবিক প্রস্তুবত

ICT

Lecture: 01
টপিক:
Introduction to Computer System

Mentor:
Md. Ferdos Kabir
General Education(ICT)
38th BCS
 ❑ Class Overview
➢ Introduction to Computer
➢ Types of Computer
➢ History of Computer
➢ Different Components of a Computer
➢ Computer System
➢ Number System

❑ Introduction to Computer
A Computer…
❖ Takes input
❖ Processes it according to stored instructions
❖ Produces results as output

The word computer was taken from the Latin – Computare – which
means ‘calculate’
Computer is a machine (e -Device) that only can execute instructions that
given by the user and operate the data based on the related instruction.
The computer will process the data to produce information.

Functionality
❖ Accepts data Input (e.g. Typing on keyboard)
❖ Processes data Processing (e.g. Calculation)
❖ Produces output Output (e.g. Displaying text)
❖ Stores results Storage (e.g. On a hard drive)

❑ Types of Computer
❑ Personal Computers (PC): Used by individuals for general tasks like
browsing the internet, word processing, and gaming.
❑ Laptops: Portable computers that integrate all the components of a
PC into a compact form.
❑ Tablets: Touchscreen devices that are highly portable and often
used for media consumption and light computing tasks.
❑ Embedded Computer: A combination of hardware and software,
designated to perform a highly specific function like central heating
systems, engine management systems in vehicles and so on.
❑ Servers: Powerful computers that provide services to other
computers over a network.
❑ Mainframes: Large, powerful systems used for large-scale
computing tasks in industries like banking and insurance.
❑ Supercomputers: Extremely fast computers used for complex
scientific calculations and simulations.

❑ History- Early Developments

▪ Abacus: An ancient tool used for arithmetic calculations.
▪ Pascaline: Invented by Blaise Pascal in 1642, capable of performing
addition and subtraction.
▪ Leibniz Wheel: Developed by Gottfried Wilhelm Leibniz, it could
perform all four arithmetic operations.
▪ Charles Babbage: Known as the "father of the computer," he
designed the Analytical Engine in the 1830s, which had the basic
elements of a modern computer.
• First Generation (1940s-1950s):
o Technology: Vacuum tubes.
o Example: ENIAC (Electronic Numerical Integrator and
Computer).
• Second Generation (1950s-1960s):
o Technology: Transistors.
o Example: IBM 7090.
• Third Generation (1960s-1970s):
o Technology: Integrated Circuits (ICs).
o Example: IBM System/360.
• Fourth Generation (1970s-Present):
o Technology: Microprocessors.
o Example: Intel 4004.
• Fifth Generation (Present and Beyond):
o Technology: Artificial Intelligence (AI) and Quantum
Computing.
 ❑ Components of a Computer

• Input Devices: Devices used to provide data to the computer (e.g.,

keyboard, mouse).
• Output Devices: Devices that receive data from the computer and
present it to the user (e.g., monitor, printer).
• Central Processing Unit (CPU): The brain of the computer that
processes instructions.
• Memory: Temporary (RAM) and permanent (ROM) storage used by
the CPU.
• Storage Devices: Devices for long-term data storage (e.g., HDD, SSD).
• Motherboard: The main circuit board connecting all components.
• Power Supply Unit (PSU): Converts electrical power to a usable form
for the computer.
• Peripheral Devices: Additional devices that enhance the computer's
functionality (e.g., external drives, USB devices).
 ❑ Input Devices

• Keyboard:
o Function: Primary device for text input.
o Types: Mechanical, membrane, ergonomic.
• Mouse:
o Function: Pointing device for graphical user interface
interaction.
o Types: Optical, laser, trackball.
• Scanner:
o Function: Converts physical documents into digital format.
o Types: Flatbed, sheet-fed, handheld.

❑ Output Devices

• Monitor:
o Function: Displays visual output from the computer.
o Types: LCD, LED, OLED.
• Printer:
o Function: Produces physical copies of digital documents.
o Types: Inkjet, laser, dot matrix.
• Speakers:
o Function: Output audio signals.
o Types: Built-in, external, surround sound systems.

❑ Central Processing Unit-CPU

Central Processing Unit (CPU)
• Definition: The brain of the computer where most
calculations take place.
• Components:
o Control Unit (CU): Directs operations of the
processor.
o Arithmetic Logic Unit (ALU): Performs arithmetic
and logical operations.
o Registers: Small storage locations for quick data
access.
• Performance Metrics: Clock speed (GHz), number of
cores, thermal design power (TDP).
 ❑ Memory

• RAM (Random Access Memory):

o Function: Temporary storage that is fast and volatile, used by
the CPU for active tasks.
o Types: DDR3, DDR4, DDR5.
• ROM (Read-Only Memory):
o Function: Permanent storage for system firmware, not easily
writable.
o Printer, keyboards and other peripherals device use ROM to
store instructions
o Types: BIOS (Basic Input Output System, firmware chips).
• Cache Memory:
o Function: Small, fast memory located close to the CPU to
speed up access to frequently used data.
o Levels: L1 (smallest, fastest), L2, L3 (largest, slowest).

❑ Storage Devices

• Hard Disk Drive (HDD):

o Function: Traditional storage device with spinning disks.
o Characteristics: Larger capacity, slower speed.
• Solid State Drive (SSD):
o Function: Faster storage device with no moving parts.
o Characteristics: Faster speed, higher cost, lower capacity
compared to HDD.
• M.2 NVMe SSD:
o Function: A type of SSD that connects directly to the
motherboard.
o Characteristics: Even faster data transfer rates, used in high-
performance applications.
 ❑ Motherboard

• Definition: The main circuit board that holds the CPU, memory, and
other essential components.
• Components:
o Chipset: Manages data flow between the CPU, memory, and
peripherals.
o CPU Socket: Connects the CPU to the motherboard.
o RAM Slots: Hold the RAM modules.
o Expansion Slots: For additional cards like GPUs, sound cards.
o Power Connectors: Provide power to the CPU and other
components.
o Data Connectors: For connecting storage devices and
peripherals.
 ❑ Power Supply
Power Supply Unit (PSU)
• Definition: Converts electrical power from an outlet into usable
power for the computer's components.
• Specifications:
o Wattage: Total power output capacity.
o Efficiency Rating: Indicates how efficiently the PSU
converts power (e.g., 80 Plus certification).
o Connectors: Types of connectors for powering various
components (e.g., ATX, SATA, PCIe).

❑ Computer System
All of the components of a computer system can be summarized with the
simple equations.
Computer System = HARDWARE + SOFTWARE+ USER

• Hardware = Internal Devices + Peripheral Devices

All physical parts of the computer (or everything that we can touch) are
known as Hardware.
• Software = Programs, Software gives "intelligence" to the computer.
• User = Person, who operates computer.

❑ Types Of Software
System Software
Operating System (like Windows and Linux)
Language Processor (converts the human-readable language into a
machine language and vice versa)
Device Driver (device like a printer, mouse, modem, etc. needs a driver)

Application Software
General Purpose Software (MS-Word, MS-Excel, PowerPoint, etc.)
Customize Software (railway reservation system, airline reservation
system, invoice management system, etc.)
Utility Software (antivirus, disk fragmented, memory tester, disk repair,
disk cleaners, registry cleaners, disk space analyzer, etc.)

❑ Number System
A number system is a way to represent and express numbers using
symbols (digits).
• A number system uses a base (or radix) to represent values.
• The base refers to the number of unique digits, including zero, that a
system uses to represent numbers.
• Each system has its own set of rules for representing.

❑ Binary Arithmetic
Binary Number System
• Uses only two digits: 0 and 1.
• Base is 2.
Binary Addition
0+0=0
0+1=1
1+0=1
1 + 1 = 10 (which is 0 with a carry of 1)
Example: Stepwise:
1011 1 + 1 = 0 carry 1
+ 1101 1 + 1 + carry 1 = 1 carry 1
-------- 0 + 1 + carry 1 = 0 carry 1
11000 1 + 1 carry 1 = 1 carry 1
Carry 1 added in front

Binary Subtraction
0-0=0
1-0=1
1-1=0
0 - 1 = 1 (borrow 1 from left)
Example
1011
- 0101
------
0110

The END 