Chap 8 Computer Hardware

Computer hardware is the physical parts of a computer, including internal

components and external devices.
Internal Components:
 Motherboard: The main circuit board that connects all the other
components. It contains the CPU, RAM, and other components.
 Central Processing Unit (CPU): The "brains" of the computer that interprets
and executes commands.
 Random Access Memory (RAM): The memory used to run programs and
process information.
 Hard disk drive (HDD): An older type of storage device that uses magnetic
disks to store information.
 Solid-state drive (SSD): A newer type of storage device that uses flash
memory chips to store information.
 Power Supply Unit (PSU): The cord that plugs into the wall to provide power
to the computer.
External Devices:
 Monitor: Displays information on a screen
 Mouse: A small device used to point and select on the screen
 Keyboard: A device used to input data
 Speakers: An output device that produces sound
 Printer: An output device that produces printed copies
 Card reader: A device that reads information from portable storage devices
like SD cards.

Motherboards
Introduction to motherboard:
The motherboard serves as a single platform to connect all of the parts of a computer
together. It can be considered as the backbone of the computer.
A computer is an electronic device that processes data with respect to the user’s
requirements using IO devices. The data processing takes place in a processor, an
important component. The processor is situated in a hardware circuit board called
the motherboard or printed circuit board (PCB).
It connects the CPU, memory, hard drives, optical drives, video card, sound card,
and other parts. It also connects expansion cards directly or via cables.

Working of Motherboard:
The power supply transfers electricity to the motherboard so that the computer can
use it when you turn on the computer. Data buses are used to transfer information
between the southbridge and northbridge component of motherboard.
The northbridge motherboard component is used to make the data connections to the
CPU, RAM, or PCIe. The RAM starts feeding the CPU inputs. Depending on the
type of card which you have, after being written to the PCIe the data is either copied
or relocated to the expansion card.
The southbridge motherboard component controls the data connection to the BIOS,
the universal serial bus (USB), the serial advanced technology attachment (SATA),
and the PCI bus. Now your computer starts because signals are sent to BIOS.
The left components interact via an electrical signal. A microchip’s northbridge or
southbridge elements pass through data buses. The data will be encoded into a
programming language (1 and 0). When a signal is transferred to a motherboard, the
motherboard will start processing and translate information into a language the other
component can comprehend.
Components of Motherboard:
A motherboard is made of plastic and silicon as well. It is a hub of computer systems.
A motherboard is a complex component with various kinds of ports, slots, cables
connected to it.
Some of them are:
Chipset:
A chipset is a collection of semiconductor chips (or circuits) on the motherboard that
facilitates communication between the CPU, memory, expansion cards, and
peripheral devices. It serves as the foundation of the motherboard and consists of
one or more integrated circuit chips.
The chipset works closely with the CPU to manage memory access, data transfer
between components, and control of buses on the motherboard. Since it determines
compatibility with processors, a chipset must match the CPU it is designed for.
Types of Chipsets: Northbridge and Southbridge
Chipsets are traditionally divided into two main categories:
Northbridge
  Manages communication between high-speed components such as the CPU,
RAM, and graphics card (AGP/PCIe slots).
 Directly connects to the processor for faster data transfer.
Southbridge
 Handles input/output functions, including USB ports, audio, SATA drives,
and PCI slots.
 Works as an intermediary between the Northbridge and slower peripherals.
Processor Sockets or Slots
The central processing unit (CPU), often referred to as the brain of the computer,
performs most of the system’s calculations and processing tasks. The CPU is
installed on the motherboard using either a socket or a slot, depending on the type
of processor.
A CPU socket is a flat, square-shaped connector on the motherboard with several
rows and columns of holes for CPU pins. Most modern CPU sockets follow the Pin
Grid Array (PGA) or Land Grid Array (LGA) design.
 Pin Grid Array (PGA) – The CPU has pins on its underside that fit into the
socket. Common in AMD processors.
 Land Grid Array (LGA) – The socket has pins, and the CPU has flat contact
points. Used in Intel processors.
 Ball Grid Array (BGA) – The CPU is permanently soldered to the
motherboard, commonly found in laptops and embedded systems.

Memory Slots and External Cache

Memory Slots
Memory slots are connectors on the motherboard where RAM (Random Access
Memory) is installed. More slots mean higher RAM capacity.
Common Memory Slot Types:
 DIMM (Dual In-line Memory Module) – Used in desktops and servers.
 SO-DIMM (Small Outline DIMM) – Used in laptops.
 MiniDIMM & MicroDIMM – Used in compact devices.
Common DIMM Pin Configurations:
 168-pin – SDRAM.
 184-pin – DDR SDRAM.
 240-pin – DDR2, DDR3.
 288-pin – DDR4, DDR5.
External Cache (L1, L2, L3)
Cache memory is a small, high-speed memory inside the CPU that stores frequently
used data.
Types of Cache:
 L1 Cache – Fastest, built into the CPU.
 L2 Cache – Larger, inside or near the CPU.
 L3 Cache – Shared among CPU cores, slower but bigger.
Daughterboard:
A daughterboard (also called a daughter card, piggyback board, or riser card) is a
small circuit board that connects directly to a motherboard or an expansion card. It
helps expand or enhance the computer's functionality without replacing the entire
system.
But when we are talking about technology, no daughterboard can be found in any of
our desktop computers or laptops because they have been replaced with PCI Cards,
Onboard and ISA cards. There are a small number of laptops still using
Daughterboard.

Why Are Daughterboards Important?

Daughterboards play a key role in upgrading and improving a computer’s
performance by:
 Adding extra features like more memory, better graphics, or additional ports.
 Providing cost-effective upgrades instead of replacing the entire motherboard.
 Offering flexibility for customization in specialized tasks (e.g., gaming,
networking, audio production).
Types of Daughterboards and Their Functions
1. RAM Expansion Boards (RAM DIMMs)
 RAM expansion boards, commonly known as RAM DIMMs (Dual In-
Line Memory Modules), are daughterboards that connect to a slot on
the motherboard to increase a computer’s memory capacity.
 Adding more RAM allows the system to run multiple applications
smoothly and enhances performance in tasks such as gaming, video
editing, and software development.
2. Storage Expansion Boards (M.2 SSDs, SATA Cards)
 Storage expansion boards, such as M.2 SSDs and SATA expansion
cards, provide additional storage space for computers. M.2 SSD
daughterboards connect directly to the motherboard and offer high-
speed data transfer, making them ideal for laptops and compact
systems.
 SATA expansion cards allow users to add extra hard drives or solid-
state drives to increase storage capacity.
3. Graphics Cards (GPU – Graphics Processing Unit)
 Graphics cards, also known as GPUs, are a type of daughterboard that
enhances a computer’s graphical processing capabilities. These boards
connect to the motherboard via PCIe slots and are essential for gaming,
3D rendering, video editing, and other graphics-intensive applications.
 A powerful GPU improves frame rates, rendering speed, and overall
visual quality.
4. Network Interface Cards (NICs)
 Network interface cards (NICs) are daughterboards that provide wired
or wireless network connectivity.
 These boards enable computers to connect to the internet or local
networks via Ethernet, Wi-Fi, or Bluetooth. NICs are particularly useful
 for upgrading older computers with modern networking features or
improving network speed and reliability.
5. Audio Processing Boards (Sound Cards)
 Audio processing boards, commonly known as sound cards, are
daughterboards that enhance a computer’s audio capabilities.
 While most modern motherboards come with built-in sound processors,
dedicated sound cards provide superior sound quality, lower latency,
and additional audio features. These are especially beneficial for music
production, gaming, and professional audio editing.
6. Customization Boards (Special-Purpose Daughterboards)
 Customization boards are specialized daughterboards designed for
specific applications, such as industrial automation, robotics, scientific
research, and embedded systems.
 These boards allow users to add unique functionalities to their
computers without modifying the motherboard. They are widely used
in industries that require custom computing solutions for specialized
tasks.

Expansion Slots
These slots are especially used to install various devices to expand its capabilities.
We can install sound card, graphics cards, network card, etc on these slots. Each type
of expansion slot differs in appearance and functions. The most common types of
expansion slots on a typical motherboard of today’s computer are as:
 PCI
 AGP
 PCIe
Types of Expansion Slots
1. PCI (Peripheral Component Interconnect)
 Introduced by Intel in 1992.
 A common legacy expansion slot found in older computers.
 Used for adding sound cards, network cards, USB expansion cards, modems,
and low-end graphics cards.
 Appearance: Usually white and around 3 inches long.
 Operates at speeds of 133 MB/s (32-bit) or 266 MB/s (64-bit).
 Though still present on some motherboards, it has been largely replaced by
PCIe.
2. AGP (Accelerated Graphics Port)
 Introduced by Intel in 1996 specifically for graphics cards.
 Provides a dedicated, high-speed connection between the graphics card and
the CPU.
 Faster than PCI because it offers a direct path to system memory, reducing
bottlenecks.
 Appearance: Brown slot, usually located next to PCI slots.
 AGP speeds range from AGP 1x (266 MB/s) to AGP 8x (2.1 GB/s).
 Obsolete today, replaced by PCIe slots.
3. PCIe (Peripheral Component Interconnect Express)
 Modern and fastest expansion slot, introduced in 2003.
 Replaces both PCI and AGP slots.
 Designed for high-performance components like gaming GPUs, high-speed
SSDs, and network adapters.
 Uses a serial connection, allowing for higher bandwidth and scalability.
 Operates at speeds of 1 GB/s - 16 GB/s per lane.

4.ISA (Industry Standard Architecture)

o Very old standard, used in early PCs.
o Speed: Up to 8 MB/s (16-bit, 8 MHz).
o Rarely found in modern systems.
5.M.2 Slot
o Compact slot for SSDs and other devices.
o Uses PCIe or SATA interfaces.
o Uses: High-speed storage (NVMe SSDs), Wi-Fi cards.
6.CNR (Communication and Networking Riser)
o Designed for modems and network cards.
o Rarely used today.
7.AMR (Audio/Modem Riser)
o Used for audio and modem cards.
o Obsolete.
BIOS:
The BIOS (basic input/output system) is firmware stored on a non-volatile memory
chip (typically EEPROM or Flash memory) on the motherboard. It is the first
program that runs when you turn on your computer.
First Software to Run: When the computer is turned on, BIOS initializes and tests
the hardware components (a process called POST - Power-On Self-Test) before
loading the operating system.
Low-Level Interface: BIOS provides a low-level interface for configuring hardware
settings and managing system resources.

Function of BIOS:
1. Power-On Self-Test (POST)
o Checks the integrity and functionality of hardware components (e.g.,
CPU, RAM, storage devices).
 o If an error is detected, BIOS emits beep codes or displays error
messages.
2. Hardware Initialization
o Initializes and configures hardware components (e.g., CPU, RAM,
GPU, storage devices).
o Ensures all hardware is ready for the operating system to take over.
3. Bootstrap Loading
o Locates and loads the operating system from the boot device (e.g., hard
drive, SSD, USB).
o The boot order can be configured in the BIOS settings.
4. Hardware Configuration
o Provides a setup utility (BIOS Setup) to configure hardware settings,
such as:
 System date and time.
 Boot order.
 CPU and memory settings.
 Enabling/disabling hardware components (e.g., USB ports,
network adapters).
5. Low-Level Hardware Control
o Manage communication between the operating system and hardware
devices.
o Provides basic input/output operations for devices like keyboards,
displays, and storage.
6. Security Features
o Includes password protection to restrict access to the BIOS settings.
o Supports hardware-based security features like Secure Boot and TPM
(Trusted Platform Module).
Types of BIOS:
1. Legacy BIOS (Older Systems)
o Works in 16-bit mode (limited features and slow).
o Only support drives up to 2TB (MBR partitioning).
o Cannot boot from GPT-partitioned drives.
2. UEFI (Unified Extensible Firmware Interface) (Modern Systems)
o Works in 32-bit or 64-bit mode (faster and more powerful).
o Support drives larger than 2TB (GPT partitioning).
o It has a graphical interface with mouse support.
o Provides security features like Secure Boot (prevents malware from
modifying boot files).
CMOS Chip
 CMOS (Complementary Metal-Oxide Semiconductor) is a type of memory
chip that stores important computer settings, such as the system clock (date
and time), even when the computer is powered off.
 The CMOS chip is powered by a CMOS battery, a small cylindrical battery
that keeps these settings intact when the system is unplugged.
 CMOS memory is used to store BIOS settings, including boot order, hardware
configuration, and system preferences, allowing the system to load custom
configurations upon startup.
 The CMOS battery is designed to last for several years, but if it runs out of
power, the system may lose the stored settings, resulting in errors like
incorrect time or failure to boot.
 CMOS chips are widely used in analog circuits, such as image sensors, which
are used in cameras and scanners.
 It also plays a role in data conversion and in highly integrated transceivers for
communication systems, such as in mobile devices and network equipment.
  CMOS technology is energy-efficient, as it consumes very little power,
making it ideal for battery-powered devices and systems.

Integrated Circuits (IC): IC is also very important component of motherboard.

Integrated circuit is used for data processing and storage
USB Port: You can attach hardware like a mouse and keyboard to your computer
using the USB port.
Heat Sink: The heat created by the computer processor is absorbed and dispersed
by the heat sink. Its main function is to cool down the CPU by absorbing the heat
while the system is running.
Power Connector: The purpose of the power connector is to give power to the
motherboard.

Switched Mode Power Supply (SMPS)

The disadvantages of LPS such as lower efficiency, the need for large value of capacitors to reduce
ripples and heavy and costly transformers etc. are overcome by the implementation of Switched
Mode Power Supplies.

The working of SMPS is simply understood by knowing that the transistor used in LPS is used to
control the voltage drop while the transistor in SMPS is used as a controlled switch.
Working
The working of SMPS can be understood through the following stages:

1. Input Stage
The AC mains supply (typically 50Hz) is directly fed to a rectifier and filter circuit without using
a transformer. The rectifier converts AC to unregulated DC voltage, while the capacitor filters
out fluctuations. This unregulated DC is then supplied to the switching section.

2. Switching Section
A high-speed switching device, such as a Power Transistor or MOSFET, rapidly turns ON and
OFF to regulate the power transfer. This switching process controls the voltage supplied to the
transformer, which is significantly smaller and more efficient than those used in LPS.

3. Output Stage
The transformer output is again rectified and filtered to obtain the desired regulated DC voltage.
This output is sent to the control circuit, which ensures stable voltage by adjusting the switching
process.

4.Control Unit (Feedback Mechanism)

This section ensures voltage regulation through a feedback circuit.

 The output sensor monitors the voltage and sends feedback to the control unit.
  A comparator (error amplifier) compares the output voltage with a predefined reference
voltage.

 The chopping frequency is adjusted accordingly, controlling the duty cycle of the
switching device.

 A PWM oscillator generates a fixed-frequency Pulse Width Modulated (PWM) signal to

regulate the final output.

This feedback mechanism ensures that the SMPS maintains a stable voltage output regardless of
input fluctuations.

We can get a better idea on the complete functioning of SMPS by having a look at the following
figure.

Advantages:
 High Efficiency – SMPS achieves 80–90% efficiency, making it highly
energy-efficient.
 Lower Heat Generation – Due to minimal power dissipation, less heat is
produced.
 Compact Size – The absence of bulky transformers makes SMPS smaller and
lighter.
 Reduced Power Wastage – Unlike traditional power supplies, SMPS regulates
power efficiently without excessive losses.
  Minimal Harmonic Feedback – It reduces harmonic distortion in the main
power supply.
 Cost-Effective Manufacturing – The components used in SMPS are
affordable, lowering overall production costs.
 Multiple Output Voltages – It can provide various output voltage levels,
making it versatile for different applications.
Disadvantages:
 High-Frequency Noise – Due to rapid switching operations, SMPS generates
electrical noise.
 Complex Circuit Design – The design and implementation of SMPS are more
complicated than traditional linear power supplies.
 Electromagnetic Interference (EMI) – The switching action causes EMI,
which can interfere with nearby electronic devices.

Basic Concepts of Microprocessor

Microprocessor Overview:
A microprocessor is often referred to as the "brain" of a computer. It's a single
Integrated Circuit (IC) that executes instructions and performs operations for a
computer system. Introduced in 1971 by Intel with the Intel 4004, microprocessors
have evolved significantly in terms of performance and capability.
Block Diagram of a Microcomputer
A microprocessor consists of an ALU, control unit and register array.
Where ALU performs arithmetic and logical operations on the data received from
an input device or memory. Control unit controls the instructions and flow of data
within the computer. And, register array consists of registers identified by letters
like B, C, D, E, H, L, and accumulator.
Parts of a Microprocessor:
1. CPU (Central Processing Unit)
o The core unit responsible for data processing. It contains:
 Arithmetic and Logical Unit (ALU): Performs mathematical and
logical operations.
 Control Unit (CU): Directs the operation of the processor,
ensuring tasks are completed in order.
 Registers: Small, fast storage locations used to hold data
temporarily.
 Decoder: Decodes high-level instructions into machine language.
 Instruction Register (IR): Holds the current instruction being
executed.
2. Bus Architecture
o A system of communication pathways used for transmitting data
between components. It includes:
 Address Bus: Carries memory addresses.
 Data Bus: Carries data between components.
 Control Bus: Manages the operations of other buses and the flow
of instructions.
3. Memory
o Primary Memory (Volatile): Stores data temporarily. Types include:
 RAM (Random Access Memory): Stores data temporarily while
the system is running.
  ROM (Read-Only Memory): Stores permanent instructions that
cannot be changed.
o Secondary Memory (Non-volatile): Stores data permanently. Examples
include CDs, DVDs, external drives.

Basic Tasks of a Microprocessor:

1. Arithmetic Operations: Performing calculations like addition, multiplication,
etc., using the Arithmetic Logic Unit (ALU).
2. Data Movement: Moving data between different memory locations or I/O
devices.
3. Control Unit (CU): Keeps track of the next instruction using the Program
Counter (PC), ensuring instructions are processed in the correct order.
Characteristics of a Microprocessor:
1. Clock Speed
o Determines how fast a microprocessor can execute instructions.
Measured in MHz (Million cycles per second) or GHz (Billion cycles
per second).
2. Word Size
o Refers to the number of bits a microprocessor can handle in a single
instruction. Common word sizes today are 32-bit or 64-bit.
3. Instruction Set
o A set of machine-level commands the microprocessor can execute, such
as arithmetic, logical operations, data transfer, etc.
Types of Microprocessors on the basis of architecture:
1. CISC (Complex Instruction Set Computer)
o Features complex instructions capable of performing multiple tasks in
one go (e.g., loading data, performing arithmetic operations).
 o Examples: Intel 386, 486, Pentium.
2. RISC (Reduced Instruction Set Computer)
o Simplifies instructions to execute more quickly, often completing
operations in one clock cycle.
o Examples: IBM RS6000, DEC Alpha.
3. EPIC (Explicitly Parallel Instruction Computing)
o Executes instructions in parallel using compilers, improving
performance with fewer clock cycles.
o Examples: IA-64 (Intel Architecture-64).
Features of a Motherboard
 Supports various components (CPU, RAM, storage, expansion cards).
 Compatible with specific CPUs and memory types.
 Requires compatible video cards, sound cards, and storage devices.
 Must work with a matching power supply and case.
Functions of a Motherboard
 Acts as the backbone of the computer, connecting all components.
 Provides expansion slots for additional devices.
 Distributes power to all components from the power supply.
 Enables data transfer between the CPU, memory, and other devices.
 Houses the BIOS/UEFI firmware for system configuration.