Personal Computer Hardware Basics

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Personal Computer Basics

Contents
What is a computer?
Computers simplified
Different types of computers-Desktops, Laptops, Different types of computers
Desktop Computer Hardware Basics
• Computer Case (Cabinet)
• Motherboard
• Chipset
• CPU: clock speed, Over-clocking, Data bus, Cache
• Memory
• Hard Drive
• Solid State Drive
• Power supply unit
• Expansion cards: Video Card/Network cards
• Removable media
• Keyboard: Mechanical/Optical
• Mouse, Moue alternatives
• Peripherals for connecting with computer: Printer, Scanners, Speakers /Headphones,
Microphones, Web Cameras, Gaming devices Joystick, Game pad, Game controller
• Monitor: TFT,LED, LED v/s LCD
• Power Cord
• The other features which are available on Laptops vis-à-vis Desktops
• Ports









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What is a computer?
A computer is an electronic device that manipulates information, or "data." It has the ability to store,
retrieve, and process data. You can use a computer to type documents, send email, and browse the
internet. You can also use it to handle spreadsheets, accounting, database management,
presentations, games, and more.
Computers Simplified?
All types of computers consist of two basic parts :
• Hardware is any part of your computer that has a physical structure, such as the computer
monitor or keyboard.
• Software is any set of instructions that tells the hardware what to do. It is what guides the
hardware and tells it how to accomplish each task. Some examples of software are web
browsers, games, and word processors such as Microsoft Word.
Different types of computers?
When most people hear the word "computer" they think of a personal computer such as a desktop
or laptop computer. However, computers come in many shapes and sizes, and they perform many
different functions in our daily lives. When you withdraw cash from an ATM, scan groceries at the
store, or use a calculator, you're using a type of computer.
Desktop Computers
Many people use desktop computers at work, home, school, or the library. Most desktop computers
are easy to upgrade and expand, or add new parts. Another benefit of desktop computers is the
cost. Some desktop computers have a built-in monitor to save space. These are often called all-in-
one desktop computers.
Laptop Computers
The second type of computer that you may be familiar with is a laptop computer, or laptops as they
are often referred to. Laptops are battery or AC-powered personal computers that are more
portable than desktop computers, allowing you to use them almost anywhere.
Since a laptop is smaller than a desktop, it's more difficult to access the internal components. That
means you may not be able to upgrade them as much as a desktop. However, it's usually possible to
add more RAM or a bigger hard drive.
Other Types of Computers
Today, there lots of everyday devices that are basically specialized computers, even though we don't
always think of them as computers. Here are a few common examples:
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• Tablet Computers: These use a touch-sensitive screen for typing and navigation. Since they
don't require a keyboard or mouse, tablet computers are even more portable than laptops.
The iPad is an example of a tablet computer.
• Mobile Phones: Many mobile phones can do a lot of things a computer can do, such as
browsing the internet or playing games. These phones are often called smartphones.
• Game Consoles: A game console is a specialized kind of computer that is used for
playing video games. Although they are not as fully-featured as a desktop computer, many
newer consoles, such as the Nintendo Wii, allow you to do non-gaming tasks like browsing
the internet.
• TVs: Many TVs now include applications (or apps) that let you access various types of online
content. For example, you can view your Facebook news feed or watch streaming movies
on Netflix.
Desktop Computer Hardware Basics
The basic parts of a desktop computer are the computer case, Motherboard, Chipset, CPU, Memory
monitor, keyboard, mouse, power supply and power cord.
Computer Case (Cabinet)
The computer case is the metal and plastic box that contains the main components of the computer.
It houses the motherboard, central processing unit (CPU), the power supply, and more. Computer
cases come in different shapes and sizes. Based on their form factors, they are nowadays referred to
as Tower PC’s, Slim Form Factors or Ultra Small Form factor devices.
Motherboard

The motherboard is the main component inside the case. It is a large rectangular board with
integrated circuitry that connects the other parts of the computer including the CPU, the RAM, the
disk drives (CD, DVD, hard disk, or any others) as well as any peripherals connected via the ports or
the expansion slots.

Chipset

The Chipset is made up of two main chips: the Northbridge and Southbridge chips. Popular chipset
manufacturers include nVidia, Intel, AMD, SiS, VIA, and ATI. The Northbridge chip handles the faster
communication needs of the computer like communication with CPU, video card slot, RAM, and the
Southbridge chip. The Northbridge is also known as the Memory Controller Hub (MCH), or
Integrated Memory Controller (IMC). The Southbridge controls the slower I/O or in-and-out devices
like Communication with hard drive and expansion slots, USB, system clock. The Southbridge chip is
sometimes referred to as the I/O Controller Hub (ICH), or Platform Controller Hub (PCH).Recently, in
newer configurations, the northbridge and southbridge have been consolidated into a single IC, the
"Platform Controller Hub" (PCH), effectively an enhanced southbridge and with the 16x PCIe
interface controller being integrated into the CPU itself.

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CPU (Processor)

The CPU (Central Processing Unit) executes most of the instructions & commands and performs
calculations to carry out tasks which enable a computer to function, and is sometimes referred to as
the "brain" of the computer. It is usually cooled by a heat sink and fan. Most new CPUs include an
on-die Graphics Processing Unit (GPU).
A processor's speed is measured in gigahertz (GHz), or billions of instructions per second(the actual
speed of the computer depends on the speed of many different components - not just the
processor)

Present Industry Technology – Currently 3rd Generation CPU’s are used which are based on Intel’s
22nm architecture.
Upcoming Technology –Coming Apr-May’13, Intel plans to announce it’s 4th generation of CPU’s
which promises atleast 10% CPU performance increase over current generation along with
noticeable improvement in Graphics capability.

What is a Dual Core Processor?
A dual core processor is a CPU with two separate cores on the same die, each with its own cache. It's
the equivalent of getting two microprocessors in one.

What is Clock Speed?
Clock speed is a measure of how quickly a computer completes basic computations and operations.
It is measured as a frequency in hertz. A megahertz is one-million cycles per second, while a
gigahertz is one-billion cycles per second. So a computer with a clock speed of 800MHz is running
800,000,000 cycles per second, while a 2.4GHz computer is running 2,400,000,000 cycles per second.

What is Overclocking?
Overclocking is the practice of making computer components operate beyond their stock
performance levels by manipulating the frequencies at which the component is set to run, and,
when necessary, modifying the voltage sent to the component to allow it to operate at these higher
frequencies more stably.

What Is a Data Bus?
A data bus transfers data from one component to another on a motherboard. This can include
transferring data to and from the memory, or from the central processing unit (CPU) to other
components. Every data bus is designed to handle so many bits of data at a time. The amount of
data a data bus can handle is called bandwidth.

There are three main buses in most computers:


1) PCI Bus- The PCI bus connects your expansion cards and drives to your processor and other sub
systems. On most systems the bus speed of the PCI bus is 33MHz. If you go higher than that, then
cards, drives, and other devices can have problems. The exception to this is found in servers. In some
servers you have a special 64-bit (extra wide) 66MHz PCI slots that can accept special high-speed
cards. Think of this as a double sized passing lane on a major road that allows higher cars to go
through.

2) AGP Bus-The AGP bus connects your video card directly to your memory and processor. It is very
high speed compared to standard PCI and has a standard speed of 66MHz. Only one device can be
hooked to the AGP bus as it only supports one video card so the speed is better compared to the PCI
bus, which has many devices on it at once.
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3) Front Side Bus (FSB) - The Front Side Bus is the most important bus to consider when you are
talking about the performance of a computer. The FSB connects the processor (CPU) in your
computer to the system memory. The faster the FSB is, the faster you can get data to your
processor. The faster you get data to the processor, the faster your processor can do work on it. The
speed of the front side bus depends on the processor and motherboard chipset you are using as well
as the system clock. ). If you think of the CPU as the brain of the computer, and the memory, hard
disk and other components as organs, the front side bus would be akin to the main nervous system
that links the organs to the brain.

What is Cache Memory?
Cache memory is extremely fast memory that is built into a computer’s central processing unit
(CPU), or located next to it on a separate chip. The CPU uses cache memory to store instructions that
are repeatedly required to run programs, improving overall system speed. The advantage of cache
memory is that the CPU does not have to use the motherboard’s system bus for data transfer.

There are different levels of cache:
L1-cache is the fastest cache and it usually comes within the processor chip itself.
The L1 cache typically ranges in size from 8KB to 64KB and uses the high-speed SRAM (static RAM)
instead of the slower and cheaper DRAM (dynamic RAM) used for main memory.

L2 cache comes between L1 and RAM(processor-L1-L2-RAM) and is bigger than the primary cache
(typically 64KB to 4MB).

L3 cache is not found nowadays as its function is replaced by L2 cache. L3 caches are found on the
motherboard rather than the processor. It is kept between RAM and L2 cache.

So if your system has L1,L2 and L3 cache data fetching will be L1->L2->L3->RAM
ie. If data is not there in L1 it will check L2 then L3 then RAM

Memory

The Random-Access Memory (RAM) is your system's short-term memory. Whenever your
computer performs calculations, it temporarily stores the data in the RAM until it is needed.
This short-term memory disappears when the computer is turned off. If you're working on a
document, spreadsheet, or other type of file, you'll need to save it to avoid losing it. When you save
a file, the data is written to the hard drive, which acts as long-term storage. RAM is measured
in megabytes (MB) or gigabytes (GB). The more RAM you have, the more things your computer can
do at the same time. If you don't have enough RAM, you may notice that your computer is sluggish
when you have several programs open
Present Technology – 1333 MHz
Upcoming Technology – 1666MHz

What is DDR RAM?
Double-Data-Rate Synchronous Dynamic Random Access Memory, better known as DDR SDRAM or
DDR RAM for short, is a type of very fast computer memory. DDR RAM is based on the same
architecture as SDRAM, but transfers twice the data in the same amount of time.

DDR3 RAM?

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DDR3 SDRAM, an abbreviation for double data rate type three synchronous dynamic random access
memory, is a modern kind of dynamic random access memory (DRAM) with a high
bandwidth interface. The primary benefit of DDR3 SDRAM over its immediate predecessor, DDR2
SDRAM, is its ability to transfer data at twice the rate,enabling higher bandwidth or peak data rates.
Compared to DDR2 memory, DDR3 memory uses 30% less power.
It works at 1.5 Volts

Upcoming technology: DDR3L: ”L” Refers to low voltage. It operates at 1.35Volts

The Read-Only Memory (ROM) stores the BIOS that runs when the computer is powered on or
otherwise begins execution, a process known as Bootstrapping, or "booting" or "booting up". The
BIOS (Basic Input Output System) includes boot firmware and power management firmware. Newer
motherboards use Unified Extensible Firmware Interface (UEFI) instead of BIOS.
Buses connect the CPU to various internal components and to expansion cards for graphics and
sound. Current PCI Express: for expansion cards such as graphics, sound, network interfaces, TV
tuners, etc. PCI: for other expansion cards. SATA: for disk drives.

Hard Drive

What is a Hard Drive?
The hard drive is the data center of the computer. This is where the software is installed, and it's
also where your documents and other files are stored. The hard drive is long-term storage, which
means the data is still saved even if you turn the computer off or unplug it.
When you run a program or open a file, the computer copies some of the data from the hard
drive onto the RAM so that it can access the data more easily. When you save a file, the data is
copied back to the hard drive. The faster the hard drive is, the faster your computer can start
up and load programs.

Present Industry Usage (Technology) – 5400/7200 RPM (2.5” for Notebooks and 3.5” for Desktops)

The upcoming trend: the primary competing technology for secondary storage is flash memory in the
form of solid-state drives (SSDs).

What is a Solid State Drive?
An SSD (solid-state drive or solid-state disk) is a storage device that stores persistent data on solid-
state flash memory. SSDs actually aren't hard drives at all, in the traditional sense of the term, as
there are no moving parts involved. Instead, an SSD has an array of semiconductor memory
organized as a disk drive, using integrated circuits (ICs) rather than magnetic or optical media.

This arrangement has many advantages. Data transfer to and from solid-state drives is much faster
than electromechanical disk drives. Seek time and latency is also substantially reduced. Users
typically enjoy much faster boot times as well. In general, SSDs are also more durable and much
quieter, with no moving parts to break or spin up or down. SSDs do, however, have slower write
times and a set life expectancy, as there is a finite number of erase/write cycles before performance
becomes erratic.

Present Industry Usage (Technology) – 32 GB
Upcoming Technology – 128 GB/250GB

Power supply unit (computer)

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The power supply unit in a computer converts the power from the wall outlet to the type of power
needed by the computer. It sends power through the cables to the motherboard and other
components. Power supply units used in computers are nearly always switch mode power supplies
(SMPS). The SMPS provides regulated direct current power at the several voltages required by the
motherboard and accessories such as disk drives and cooling fans.

Expansion cards

Most computers have expansion slots on the motherboard that allow you to add various types
of expansion cards. These are sometimes called PCI (Peripheral Component Interconnect) cards.
You may never have to add any PCI cards, as most motherboards have built-in video, sound,
network, and other capabilities. However, if you want to boost the performance of your computer or
update the capabilities of an older computer, you can always add one or more cards. Below are
some of the most common types of expansion cards:

Video card

The video card is responsible for what you see on the monitor. Most computers have a GPU
(Graphics Processing Unit) built into the motherboard, instead of having a separate video card. If
you like playing graphics-intense games on the computer, you can add a faster video card to one of
the expansion slots to get better performance.

The prevalent graphics cards in industry are DDR3/DDR4/DDR5 types with a memory clock rate of
700-2400/2000-3600/900-5700 MHz and Bandwidth of 5.6-156.6/128-200/130-230 GB/s
respectively.

Network Card

The network card allows your computer to communicate over a network and access the internet. It
can either connect with an Ethernet cable or through a wireless connection (often called Wi-Fi).
Many motherboards have built-in network connections, and a network card can also be added to an
expansion slot.


Removable media

What is an Optical Drive?
An optical drive is a piece of equipment that uses a laser to read or write information on a disc.
Optical drives are often associated with computers, but they can stand alone as appliances. For
instance, a Digital Versatile Disc (DVD) player, Blu-Ray® disc (BD) player, and Compact Disc (CD)
players are considered optical drives even though they may not be in a computer system.

Optical discs are the most common way of transferring digital video, and are popular for data
storage as well.
Floppy disk drives for reading and writing to floppy disks, an outdated storage media consisting of a
thin disk of a flexible magnetic storage medium. These were once standard on most computers but
are no longer in common use. Floppies are used today mainly for loading device drivers not included
with an operating system release (for example, RAID drivers). USB flash drives plugs into a USB port
and do not require a separate drive. USB flash drive is a typically small, lightweight, removable, and
rewritable flash memory data storage device integrated with a USB interface. Capacities vary, from
hundreds of megabytes (in the same range as CDs) to tens of gigabytes (surpassing Blu-ray discs but
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also costing significantly more). Memory card readers for reading from and writing to Memory cards,
a flash memory data storage device used to store digital information. Memory cards are typically
used on mobile devices. They are thinner, smaller and lighter than USB flash drives. Common types
of memory cards are SD and MS. Tape drives read and write data on a magnetic tape, and are used
for long term storage and backups.

Present Industry Usage (Technology) –DVD Super Multi Drive
Upcoming Technology – Blu Ray

Keyboard
The keyboard is one of the primary ways we communicate with the computer and enter data. There
are many different types of computer keyboards such as wired, wireless, ergonomic, multimedia,
and more. Although there may be differences in the location of some keys or features, keyboards
are very similar and allow you to accomplish basically the same tasks.

Mouse - a pointing device that lets you point to objects on the screen, clicks on them, and move
them. There are two main types of mice: optical and mechanical. The optical mouse uses an
electronic eye to detect movement and is easier to clean. The mechanical mouse uses a rolling ball
to detect movement.

Mouse Alternatives:
Trackball - a pointing device consisting of an exposed protruding ball housed in a socket that detects
rotation about two axes.

Touchpad- A touchpad (also called a trackpad) is a touch-sensitive pad that lets you control the
pointer by making a "drawing" motion with your finger. Touchpads are very common on laptop
computers.


Peripherals for connecting with computer

Printer - A device that produces a permanent human-readable text or graphic document.

Laser printer
Laser printing is a digital printing process that rapidly produces high quality text and graphics
on plain paper. As with digital photocopiers and multifunction printers (MFPs), laser printers employ
a xerographic printing process, but differ from analog photocopiers in that the image is produced by
the direct scanning of a laser beam across the printer's photoreceptor.

Inkjet printer
Inkjet printing is a type of computer printing that creates a digital image by propelling droplets of
ink onto paper. Inkjet printers are the most commonly used type of printer,
[1]
and range from small
inexpensive consumer models to very large professional machines that can cost tens of thousands of
dollars

Dot matrix printer
Dot matrix printing or impact matrix printing is a type of computer printing which uses a print head
that runs back and forth, or in an up and down motion, on the page and prints by impact, striking an
ink-soaked cloth ribbon against the paper, much like the print mechanism on a typewriter. However,
unlike a typewriter or daisy wheel printer, letters are drawn out of a dot matrix, and thus, varied
fonts and arbitrary graphics can be produced.
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Thermal printer
Thermal printing (or direct thermal printing) is a digital printing process which produces a printed
image by selectively heating coated thermochromic paper, or thermal paper as it is commonly
known, when the paper passes over the thermal print head. The coating turns black in the areas
where it is heated, producing an image. Two-color direct thermal printers can print both black and
an additional color (often red) by applying heat at two different temperatures.

Scanners: A scanner allows you to copy an image or document and save it to your computer as a
digital (computer-readable) image. Many scanners are included as part of an all-in-one
printer/scanner/copier, although you can also buy a separate flatbed or hand-held scanner.

Speakers/Headphones: Speakers and headphones are output devices, which means that they are
devices that communicate information from the computer to the user. They allow you to hear sound
and music. Depending on the model, they may connect to the audio port or the USB port. Some
monitors also have built-in speakers.

Microphones: A microphone is a type of input device, or a device that receives information from a
user. You can connect the microphone to the computer and use the computer to record sound or to
communicate with another computer user over the internet. Many computers come with built-in
microphones.

Web Cameras: A web camera, or webcam, is a type of input device that can record videos or take
pictures. It can also transmit video over the internet in real time, allowing you to do video chat or
video conferencing with somebody in a different part of the world. Webcams are used often in
business, and they also help many friends and families stay connected.

Gaming devices Joystick - a hand-operated pivoted stick whose position is transmitted to the
computer.

Game pad - a hand held game controller that relies on the digits (especially thumbs) to provide
input.

Game controller - a specific type of controller specialized for certain gaming purposes.

Monitor

The monitor works with a video card, located inside the computer case, to display images and text
on the screen. Newer monitors usually have LCD (liquid crystal display) or LED (light-emitting diode)
displays. These can be made very thin, and they are often called flat panel displays. Older monitors
use CRT (cathode ray tube) displays. CRT monitors are much bigger and heavier, and they take up
more desk space.

What is a TFT Monitor?
A TFT monitor uses thin-film transistor technology for the ultimate LCD display. A TFT monitor has
as many no. of transistors as many pixels are there. Prior to TFT, LCD displays could not keep up with
fast moving images. A mouse dragged across the screen, for example, from point A to point B, would
disappear between the two points. A TFT monitor can track the mouse, resulting in a display that can
be used for video, gaming and all forms of multimedia.

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LED Backlit Monitor
LED displays are actually LCD displays that are backlit with light-emitting diodes rather than
fluorescent lights used in traditional LCD displays. This allows for greater contrast than a traditional
LCD display.


Differences between LED-backlit and conventional LCD displays
LED-backlit LCD monitors differ from conventional LCD monitors in the following:
• They can produce an image with greater dynamic contrast compared with LCD monitors.
• With Edge-LED lighting they can be extremely slim.
• Current models on the market can be less than one inch thick.
• They can offer a wider color gamut, especially when RGB-LED backlighting is used.
• Lesser environmental pollution on disposal.

Upcoming Trend:
Touch based displays will pick up in coming future.

Power Cord
The power cord is the link between the power outlet and the power supply unit in the computer
casing. If the power cord is not plugged in, the computer will not power on. To protect your
computer from voltage spikes, you can plug the power cord into a surge protector. You can also use
an Uninterruptable Power Supply (UPS), which acts as a surge protector and also provides temporary
power if there is a blackout.

The other features which are available on Laptops vis-à-vis Desktops:

• Touchpad: A touchpad (also called a trackpad) is a touch-sensitive pad that lets you control
the pointer by making a "drawing" motion with your finger. Many touchpads now
include multi-touch gestures, which allow you to perform specific tasks by making gestures
with more than one finger. For example, a pinch gesture is often used to zoom in or out.

• Battery: Every laptop has a battery which allows you to use the laptop when it's not plugged
in. Whenever you plug the laptop in, the battery recharges. Another benefit of having a
battery is that it can provide backup power to the laptop if the power goes out.
• AC Adapter: A laptop usually has a specialized power cable called an AC adapter, which is
designed to be used with that particular kind of laptop. Some of these cables use magnetic
MagSafe connectors that will safely pull out if someone trips over the power cable. This
helps to prevent damage to the cable and the laptop.

• Ports: Most laptops have the same types of ports that desktop computers have (such
as USB), although they usually have fewer ports to save space. However, some ports may be
different, and you may need an adapter in order to use them. For example, the monitor port
is often a Mini Display Port, which is a smaller version of the normal Display Port.





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Ports

In computer Hardware terminology, ‘Port’ denotes the interfaces that can be used to connect
different peripheral devices or another computer.

Port Name Used to Connect
Monitor (VGA Port) Monitor - Flat Panel or Regular
Parallel Port For printers. Not much in use now. Replaced by
USB
Serial Port Routers, Switches, Automation systems.
Replaced by USB
Power Low voltage DC Power Adapter
Phone Modem (RJ-11) Phone Line
10/100/1000 Ethernet (RJ-45 NIC) DSL Modem or Cable Modem or Network

S-Video Video In or Out
USB Printer, Keyboard, Mouse, Digital Camera
External Hard Drive, Anything with USB
connector
PS/2 Used for connecting the mouse and keyboard.
On new computers, these ports have been
replaced by USB
Stereo Sound In & Out Computer Speakers, Microphone, Stereo
Headphones
HDMI Port Consumer electronics having HDMI ports to
connect HDMI cables
e-SATA Port External HDDs advantages over the common USB
ports with higher data transfer rate.
FireWire Port High speed data transfer. It supports peer to
peer communication. Like between a scanner
and a printer is possible without the CPU
Express Card Slot Add TV Tuner Cards, Wireless Network Cards or
Sound Cards
PCIe-PCI express
PCIe X1
PCIe-X4

PCIe-X8
PCIe-X16

Eg. Network Interface cards, Sound cards
Eg. Mostly used for things like storage controllers
(RAID/SCSI/SAS/etc)
Eg. Video Card
Eg. Graphics cards
DVI Port Digital Visual Interface is a port on the computer
that makes use of full digital technique to
transfer data for high quality displays Using the
DVI Ports, digital display devices such as LCD
Monitors and LCD Projectors can display more
accurate color tones and contrast levels