What is a Computer ?
A computer is a machine that is programmed to carry out sequences of arithmetic or logical operations
automatically, enabling it to perform a wide range of tasks.
A computer system as a "complete" system includes:
• Hardware; Software; and peripheral equipment.
Computers are used to :
• control a broad range of industrial and consumer products, including devices like microwave
ovens and remote controls, and industrial robots.
• power general-purpose devices like personal computers and smartphones.
• power the Internet, which links hundreds of millions of other computers across the world.
All computers have something in common, which is the combination of both hardware and software.
Hardware is any part of your computer that has a physical structure, such as the keyboard or mouse.
It also includes all of the computer's internal parts, which you will see shortly.
Software is any set of instructions that tells the hardware what to do and how to do it.
Examples of software include web browsers, games, and word processors.
Everything you do on your computer will rely on both hardware and software.
This presentation is all about the Hardware.
Hardware and Software
When most people hear the word computer, they think of a personal computer such as a desktop or laptop.
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.
As for personal computers, there are four main systems available, which although look very different, all function in the same manner.
Types of Computers:
The different types of computers.
Traditional Desktop Computer Tablet PC
Laptop Computer All-in-One Computer
Many people use desktop computers at work, home, and school.
Desktop computers are designed to be placed on a desk, and they're typically made up of separate components, including the computer case, monitor, keyboard, and mouse.
Types of Computers:
Traditional Desktop Computer
Traditional Desktop Computer
The second type of computer you will all be familiar with is a laptop computer, commonly called a laptop.
Laptops are battery-powered computers that are more portable than desktops, allowing you to use them almost anywhere.
All of the hardware is integrated into a single unit, it also has a touchpad and not a mouse.
Types of Computers:
Laptop Computer
Laptop Computer
An All-in-One computer is a hybrid of both desktop and laptop computers.
Similar to a desktop computer but with the case and monitor built into a single unit.
Unlike a laptop, the keyboard and mouse are connected separately, and it doesn’t have a battery.
Types of Computers:
All-in-One Computer
All-in-One Computer
Tablet computers—or tablets—are handheld computers that are even more portable than laptops.
Instead of a keyboard and mouse, tablets use a touch-sensitive screen for typing and
navigation.
The iPad, or Amazon Fire are good examples of tablets.
Types of Computers:
Tablet PC
Tablet PC
Rival Computers:
PCs and Macs
• Personal computers come in two main styles:
PC and Mac.
• Both are fully functional, but they have a
different look and feel, and many people prefer one or the other.
• A bit like Marmite.
Types of Computers:
PCs and Macs
• PCs
• This type of computer began with the original IBM Personal Computer that was introduced in 1981.
• Other companies began creating similar computers, which were called IBM PC Compatible (shortened to PC).
• This is the most common type of PC,
and it usually includes the Microsoft
Windows operating system.
Types of Computers:
PCs and Macs
• Macs
• The Apple Macintosh computer was introduced in 1984, and it was the first widely sold personal
computer with a graphical user interface, or GUI (pronounced gooey).
• All Macs are made by one company
(Apple), and they almost always use
the Mac OS X operating system.
Here are a few common examples of today's specialised computers, though we don’t always think of them that way.
Smartphones:
Many cell phones can do a lot of things computers can do, including browsing the Internet and playing games.
Wearables:
Wearable technology is a general term for a group of devices— including fitness trackers and smartwatches—
that are designed to be worn throughout the day.
Game consoles:
A game console is a specialized type of computer that is used for playing video games on your TV.
TVs:
Many TVs now include applications—or apps—that let you access various types of online content. For example, you can stream video from the Internet directly onto your TV.
Types of Computers:
Other Types Of Computers
Computer Hardware: The Outer Shell
The computer case is the metal and plastic box that contains the main components of the computer, including the motherboard, central processing unit (CPU), and power supply.
The front of the case usually has an On/Off button and one or more optical drives.
Computer Hardware: The Monitor
The monitor, or screen, is your visual link to the computer, and works with a video card, located
inside the computer case, to display images and text on the screen.
A monitors usually has a LCD (liquid crystal display) or LED (light-emitting diode) display, which are
often very thin, and called flat screen monitors
Computer Hardware: The Keyboard
The keyboard is one of the main ways to communicate with a computer, and is used to input instructions or write documents.
There are many different types of keyboards, including for different languages, but most are very similar and allow you to accomplish the same basic tasks.
Computer Hardware: The Mouse
The mouse is another important tool for connecting with computers, and is known as a pointing device, it lets you point and select objects on the screen, click on them, and move them.
Computer Hardware: The Mouse
There are two main mouse types:
1. The optical mouse uses an electronic eye to detect movement and is easier to clean.
2. The mechanical mouse uses a roller ball to detect movement and requires regular cleaning to work properly.
Electronic Eye
Roller Ball
mechanical mouse optical mouse
Computer Hardware: Mouse Alternatives
There are other devices that can do the same thing as a mouse. Many people find them easier to use, and they also require less desk space than a traditional mouse.
The most common mouse alternative is the:
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 usually an integral part of a laptop computer.
Computer Hardware: Mouse Alternatives
The other alternative is the:
• Trackball: A trackball has a ball that can rotate freely. Instead of moving the device like a mouse, you can roll the ball with your thumb to move the pointer.
Computer Hardware.
• Power Supply Unit: PSU
The power supply unit or PSU, in a computer
converts the mains power from the wall socket to the type of power needed by the computer.
It sends power through cables to the motherboard and other components.
The PSU is enclosed with air vents and fans to disperse the large amount of heat generates.
Inside every PC are all manner of computer chips and circuit boards, most of which are connected to a large circuit board called a “motherboard”, so named because it's the main or "mother" for all internal components that enable your system to function.
On a traditional desktop PC, the motherboard is located near the base of the computer, (making it accessible to upgrade), and contains several slots, into which you can plug additional boards that
perform specific functions.
Computer Hardware.
The Motherboard: Home to Almost Everything
Computer Hardware.
• Microprocessors: CPU
Buried within the motherboard, is a microprocessor chip known as the Central Processing Unit or CP, this unit controls your entire computer system.
This is the BRAIN inside your system.
Microprocessors carry out all the various instructions that enable your computer to compute.
Every device and program connected to your
computer either issues or receives instructions that the microprocessor then processes.
This is the workhorse of your system because it affects just about everything your computer does.
Computer Hardware.
• Random Access Memory: RAM
Random Access Memory or 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.
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.
Because of this, many people add extra RAM to their computers to improve performance.
Computer Hardware.
• Hard Disk Drives: Long-Term Storage
The hard drive is where your software, documents, and other files are stored.
The hard drive is long-term storage, which means the data is still saved even when you turn the computer off or unplug it.
I/O System
• When you click the button on your mouse, a message is sent to the computer with
information about its screen position.
• When your mouse click is received, it's
handled by the input/output subsystem, or
Gateway to the CPU.
I/O to CPU
• The Input/Output System provides a way for the computer to interact with the other hardware.
• It also acts as a buffer to keep the CPU from being overwhelmed by outside
distractions.
• Because the I/O subsystem has decided that your mouse click is important, it will generate an instruction to the CPU.
"Hey, CPU! I’ve got
a mouse click"
Central Processor
• The CPU, or central processing unit, is the brains of the whole computer.
• The CPU’s “full time job” is to fetch and
carry out instructions it receives from the
I/O System.
Your computer's CPU is the mighty multitasker!
• While you're typing, maybe 60 words a minute, the CPU is fetching and executing billions of instructions a second.
• Yes, billions every second:
• Instructions to move your mouse around on the screen, to run that clock widget on your desktop, play your internet radio,
manage the files you're editing on the hard drive, and much, much more.
Meanwhile the computer
keeps working . . .
"Hey, CPU! I’ve got a mouse click"
Play Video
• When the CPU receives the call to action from the I/O System, it realises that it needs to know how to deal with this mouse click, so it looks up the address for the mouse program, which is held in memory, and sends a request for instructions stored there.
• Each instruction in the mouse program is duly fetched and executed.
The Mouse has been clicked !!!!
Play the Video
• Because the mouse was clicked when the cursor was positioned over a button on the monitor.
• The CPU now has to ask memory for the monitor program to find out what that button was for, and then has to ask memory for the Button Program, and light up the button to show that it’s been clicked.
• Because the Button Instruction was to show a video, the CPU asks the monitor program again for the necessary information needed to show the video associated with the button.
• After all of this action, generated from a single click of the mouse, has been processed, it can now show the video on the monitor.
Play Video “The Mouse Clicked
The Video Button"
• There was a lot of processing going on even before you saw the button on the screen light up because you clicked it.
• Now you can understand that the simple task of clicking your mouse meant that the computer had to make use of most of the critical components which are part of the computer's architecture:
• Peripherals (keyboard, mouse and screen)
• The basic input-output system,
• The CPU,
• Programs, and memory.
Without giving it a second thought !
As you can see !
Lets take a look at the ports on the side of your laptop, there will be at least four different ones.
These are the links to the world outside the computer.
In the image on the right are the more modern type of sockets or ports which are used on both desktop and laptop PCs.
You may have something else.
An explanation is on the next
page. Audio USB HDMI Network
USB
SD Card Reader
Computer Hardware.
• Ports and Sockets
Computer Hardware - Ports and Sockets
USB, short for Universal Serial Bus, is a standard type of connection for many different kinds of devices.
HDMI or High Definition Multimedia Interface is the most frequently used HD signal for transferring both high
definition audio and video over a single cable.
Ethernet - Networking cables are used to connect one network device to other network devices, such as the
Broadband Router, or to connect two or more computers to share printers, scanners etc.
Also worth mentioning is - WIFI which stands for Wireless Fidelity, originally a brand name, and is used to connect computers and other electronic equipment to the internet without using wires. WIFI has largely replaced the use of Ethernet cables.
SD Card Reader – If you have a digital camera, it is most likely that you have an SD Card on which to save your images. This slot allows you to insert the SD Card, just like an extra Hard Drive, and enables you to transfer your
photos onto the real Hard Drive inside your computer.
After looking at the myriad of hardware units, and you compare a Desktop to a Laptop - they are not so very different really, except that the Laptop is tidier and a lot less complicated.
Computer Hardware - Conclusion.
