Section 1:

Types & Components of a Computer System

Hardware is the physical (internal & external) parts of the computer system – the parts that you can touch and see.

Examples: motherboard, CPU, keyboard and monitor etc. are all items of hardware.

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Software is a collection of instructions that can be ‘run’ on a computer. These instructions tell the computer what to do.

software is also defined as programs for controlling the operation of a computer or processing of electronic data.

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Computer hardware is the physical components that make up the computer system. Hardware is useless without software to run on it.

Software is instructions that tell computer hardware what to do. Software is useless unless there is hardware to run it on.

For a computer system to be useful it has to consist of both hardware and software.

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Application software is a computer software which is designed to help the user in performing single or multiple related tasks.

System software (systems software) is computer software designed to operate and control the computer hardware and to provide a platform for running application software. System software can be separated into two different categories, operating systems and utility software

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The CPU is the 'brain' of the computer. It is the device that carries out software instructions. ◦ The Pentium processor made by Intel is an example of a CPU.

CPUs usually plug into a large socket on the main circuit board (the motherboard) of a computer. The speed of a CPU is measured in Hertz (Hz).

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Any data or instructions that are to be processed by the CPU must be placed into main memory(sometimes known as primary storage).

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Random Access Memory (RAM) is the part of the computer that temporarily stores the instructions that the computer is running, and the data it is processing.

RAM is a volatile storage device. This means that if the computer’s power is turned off the contents of RAM disappear and are lost.

When a computer is in use, its RAM will contain…

1.The operating system software

2.The application software currently being used

3.Any data that is being processed

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Read-Only Memory (ROM) is used in most computers to hold a small, special piece of software: the 'boot up'program. ◦ This software runs when the computer is switched on or

'boots up'. The software checks the computer’s hardware and then loads the operating system.

ROM is non-volatile storage. This means that the data it contains is never lost, even if the power is switched off.

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Examples include external hard drives, portable flash drives, CDs, and DVDs. These devices and media must be either plugged in or inserted into a computer in order to be accessed by the system.

Because secondary storage technology is not always connected to the computer, it is commonly used for backing up data.

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An operating system is a special piece of software that manages the general operation of a

computer system:

1. It provides a user interface so that we can interact with the device

2. It manages applications that are running on the device, starting them when the user requests,

and stopping them when they are no longer needed

3. It manages files, helping us save our work, organize our files, find files that we have saved and

load files

4. It manages the device’s memory, deciding what should be loaded into memory and what

should be removed

5. It looks after device security, preventing unauthorized access to the system

6. It manages the computer’s input and output hardware such as printers, etc.

Without an operating system, a device is of little use. But, just having an operating system running

alone on a device is also not very useful - we need to have application software (such as word

processing, spreadsheets, etc.) so that we can actually do useful tasks with the computer.

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The system that people use to interact with a

computer (to give it commands, to see the results of

those commands, etc.) is known as the user interface.

There are two that you need to be aware of:

◦ Command-Line Interface (CLI)

◦ Graphical User Interface (GUI)

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Many years ago when computers were notvery powerful they could not display the colourful graphics required for a GUI.

The only interface available to most computer uses was the ‘command line’.

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The user would see nothing but a black screen. They would have to type a command to make anything happen.

e.g. To copy a text file called NOTES from a floppy disc to the hard drive the user would have to type:

> COPY A:\NOTES.TXT C:\

The user would have to learn a whole set of strange commands so that they could make use of the computer system. Plus it was not very interesting look at – no visual clues to tell you what to do next.

This meant computers used to be quite difficult to use, so this type of interface is only really suitable for expert users.

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A GUI is an interface built around visual (graphical) things:

◦ Windows are regions of the screen used to display information

Icons are small pictures that are used to represent folders, software, etc.

Menus are lists of options the user can select from

A Pointer is an arrow that can be moved around the screen and is used to select things

WIMP GUIs are quite easy to use due to the visual nature of the interface – the user

has lots of visual clues as to what things do.

However, to display all of the nice graphics required by a GUI takes a lot of computing power so quite a powerful computer is needed.

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The early 1980s saw a revolution in computing: The creation of computers that were small enough to fit on a desk, and cheap enough that everyone could have their own, personal computer, instead of having to share access to a mainframe.

◦ These computers came to be known as desktop computers, or personal computers (PCs).

◦ A typical PC contained the same basic components as a mainframe computer (CPU, RAM, storage, etc.) but at a fraction of the size &cost.

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A 'laptop' computer is a light, compact and portable

PC.

Laptops contain a rechargeable battery so that they

can be used even when not plugged in to a mains

power supply. They also have a built-in LCD monitor.

To make them as portable as possible, most laptops try

to avoid any sort of cable or wire. Instead of a mouse,

a track pad is used. Instead of a wired connection to a

network or printer, 'wireless' radio connections are

used.

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Smaller than a laptop and bigger than a Smartphone, the tablet is perfect to take with you on the go.

Although tablets come in a variety of shapes, sizes and feature sets, they share many similar characteristics. Nearly all have a touch-screen interface and an operating system capable of running small programs.

It has the ability to use 3G/4G technology.

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a mobile phone that is able to perform many of the functions of a computer, typically having a relatively large screen and an operating system capable of running general-purpose applications.◦ Basic Functions:

Internet

Media

Photo & Video

Apps

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Advantages/Pros:◦ Access to the Internet on speeds of up to 4G allows users to keep up to

date with the world while on the go. Application stores provide functional apps for ease of use in areas such as social networking, careers and school.

Disadvantages/Cons:◦ Becoming overwhelmed by non-stop data and the stressful obligation

to keep in touch through different mediums -- i.e., text, Facebook, email -- is a disadvantage. Smartphones are more expensive than regular mobile phones, and require data plans to be completely functional.

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New technologies arethose that are currentlybeing developed or willbe developed in the next5 to 10 years, and whichwill alter the businessand social environment.

The technologies (and their impacts on everyday life) that we are going to focus on:◦ Artificial intelligence

◦ Biometrics

◦ Robotics

◦ Quantum cryptography

◦ Computer assisted translation

◦ 3D and holographic imaging

◦ Virtual reality

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This is a computer science that is focused on creating computer systems that simulate human intelligence.

The term was first used in 1956 by a computer scientist at the Massachusetts Institute of Technology (MIT) who was focused on trying to make computers behave like humans.

AI is being developed in the following areas.

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Some of the impacts that artificial intelligence can have on everyday life are discussed in the table:

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https://www.ted.com/talks/neil_harbisson_i_listen_to_color

Biometrics is where parts of a person's body are used for identification purposes. Examples are shown in the table below:

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All of these parts of the human body are unique from person to personand can be used to authenticate identity.

Before biometric methods can be useful, people have to perform a process known as 'biometric enrolment'.

Biometrics are beginning to be used in place of passwords and physical locks as a means of security.

Biometrics have advantages over these older methods as body parts cannot be lost, forgotten or stolen as can be the case with passwords and keys.

Biometrics is still a very new technology and is not yet 100% accurate.

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Robots are used to perform a wide range of physical tasks.

They are either automated (controlled by a computer chip) or manually controlled by a human.

There are 4 different types of robots: Manufacturing robots (used to perform repetitive tasks such as

welding)

Carrier robots (used by the military to carry heavy loads over dangerous terrain)

Domestic robots (used in homes to perform cleaning tasks such as vacuuming)

Exploration robots (used to visit and send images from places such as Mars)

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Some more typical tasks that robots can be used for are described in the table below:

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Robots are increasingly being used in manufacturing due to their proven increase in productivity

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Quantum cryptography (encryption) is an emerging technology that allows messages and data to be sent with complete privacy.

Older methods of encryption were based around mathematics but quantum cryptography uses physicsinstead.

This makes the encryption impossible to break.

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CAT is where a human translator uses computersoftware to help in the translation process.◦ CAT software can reduce the amount of time that the

translation takes.

Current CAT tools are not always 100% accurate. They need a human to check for errors.

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Examples of different types of CAT tools are shown in the table:

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This is a technique where images are made to appear three-dimensional and to actually have depth.◦ The two-dimensional images need to have been shot at different angles.

Holograms work by taking two regular two-dimensional images of the same object and laying one on top of the other. ◦ This creates one single image that incorporates the angles of the original

two-dimensional images. This produces a 3D effect.

Two different types of laser beams are used to record the two-dimensional images onto a single photographic plate.

When viewing the image, human eyes see it from slightly different angles. The brain combines them into a three-dimensional image.

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Virtual reality is where computers are used to create an artificial environmentthat users can interact with as if it were real.

◦ Virtual reality is not really meant for gaming purposes. It is used for more serious purposes such as: Allowing architects to walk around a virtual version of their design (this gives a better idea of what the finished building will look like)

◦ Training soldiers in combat (flight simulation, battlefield simulation)

◦ Training surgeons (virtual patients can be operated on to provide experience to trainee surgeons).

◦ As they walk around the virtual environment users will experience things in a similar way to the real world. For example: Objects get smaller as you walk away from them (and bigger as you move closer)

◦ The direction of sounds change as you move around

◦ Objects in the virtual world appear the same dimensions as they would in the real world (for example dogs are smaller than us but elephants are bigger).

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Equipment needed to create the virtual reality experience includes the following:

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Virtual reality is still a developing technology and graphicsproduced are not very realistic yet. However, experiences in the

virtual environment can seem very real.

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