Contents 1. Hardware... 2 2. Software... 4 3. Networks... 5 St Ignatius Girls JL - Form 3
1. Hardware RAM - The RAM (Random Access Memory) within your computer is where the operating system is loaded to when you switch on your computer and also where your applications are copied to when you start an application, such as a word processor or spreadsheet program. When you create data, (e.g. letters and pictures), these are initially created and held in RAM. They are copied to hard disk ONLY WHEN you save the data. As a rule of thumb, the more RAM installed in the computer the better. These days you will commonly find over 1 Gigabyte of RAM installed. ROM - The ROM (Read Only Memory) chip is a special chip held on the computer's mother board (system board). It contains software that is required to make your computer work with your operating system, for instance it is responsible for copying your operating system into RAM when you switch on your computer. The System Unit - The "system unit" is the name given to the PC box that contains the various elements of the PC. Within the system unit one finds the mother board, which contains all the main components, such as the CPU. The system unit also houses items such as the hard disk drive, the floppy disk drive and CD-ROM drives. System units come in two varieties, the tower version which stands up tall on your desk, or a desktop version, which sits flat on your desk with your monitor on top of it. What are input devices? Input devices allow you to input information to the computer. Keyboard, mouse, joystick, trackball, digital camera, webcam, scanner are examples of input devices. What are output devices? Output devices are used by a computer system to give you information. Printer, monitor, speakers are examples of output devices. What is a storage device? A computer storage device is any type of hardware that stores data. Main types of storage media include CD, DVD, USB flash drive, memory card, internal hard disk, external hard disk, network drive and online file storage. Hard Disk Drive - Hard disks are the main, large data storage area within your computer. Hard disks are used to store your operating system, your application programs (i.e. your word processor, games etc) and your data. They are much faster than CD-ROMs and floppy disks and can also hold much more data. The CPU (Central Processing Unit) The CPU performs most of the calculations within the computer and is responsible for the smooth running of your operating system (such as Microsoft Windows) as well as your application programs (such as games, word-processors, spreadsheets and databases). In many ways, the CPU is the single most important item within your computer that governs the overall speed of your computer. The CPU's speed is measured in Megahertz (MHz) or Gigahertz (GHz). The higher the MHz rating of your CPU the faster your computer will run. St Ignatius College Girls JL Page 2 of 8
Computer Performance Factors affecting overall computer speed include: 1. CPU Clock speed: The computer clock speed governs how fast the CPU will run. The higher the clock speed the faster the computer will work. The clock speed is given in megahertz (MHz). The original IBM PC ran at 4.77 MHz whereas modern PCs will run at over 3000 MHz, which gives you an idea of how far things have progressed since the introduction of the original PC. The higher the MHz speed the faster the computer. 2. RAM size: As a rule the more memory (RAM) you have the faster the PC will operate. 3. Graphics card: Graphics card s processor and memory may effect the performance of the computer system. 4. Hard disk speed and storage: The speed of a Hard disk is defined by the disk access time, which is measured in milliseconds. The smaller this access time the faster the hard disk will store or retrieve (get) data. The data storage capacity of hard disks continues to increase as new products are released. The disk storage capacity is measured in Gigabytes (GBytes). 5. Free Hard Disk Space: To get the most out of your Windows based PC, you not only need a fast hard disk but also a large hard disk with plenty of "free space". This is due to the fact Windows is constantly moving data between the hard disk and RAM (Random Access Memory). Microsoft Windows will create many so-called temporary files that it uses for managing your programs. In fact, if you have very little free hard disk space you may find that Microsoft Windows will not be able to run your programs at all. 6. Defragmenting Files: The more files become fragmented the slower the PC will work. If you are running Windows you may find that if you click on the Start menu, select Programs, and then select the Accessories / System tools group, there is a de-fragmentation program. Running this periodically may noticeably speed up the operation of your PC. When you use a PC, over a period of time the files get broken up into separate pieces that are spread all over the hard disk. De-fragmentation means taking all the broken up pieces and joining them back together again. Types of Computers Desktop computers: o Size: They fit on a desk, but are too big to carry. Users: Home users, large and small offer users. Education, Doctors. In fact just about everyone needs to know how to operate a PC these days. Laptop computers: o Portable, light weight and fit into most briefcases. o They can run on batteries as well as main power. o Notebook computers are smaller laptops. Users: Business users, people on the move, educational users. Tablet PC is a wireless personal computer that allows a user to take notes using natural handwriting with a stylus or light pen on a touch screen. Users: Personal Digital Assistants (PDA): o They combine: pen input, writing recognition, personal organisational tools, communication capabilities in a very small package. Users: Mostly business users. St Ignatius College Girls JL Page 3 of 8
2. Software Software is the collection of instructions that makes the computer work. For instance, when you type in words via the keyboard, the software is responsible for displaying the correct letters, in the correct place on the screen. Software is held either on your computer s hard disk, CD-ROM, DVD or on a diskette (floppy disk) and is loaded (i.e. copied) from the disk into the computers RAM (Random Access Memory), when required. Your favourite computer game is software. Before playing the game, you must first install the program, usually stored on a CD. Installing the program means that you copy the program or instructions that are stored on the CD onto your computer's hard disk. Types of Software 1. Operating System Software: Operating system software allows the computer system to manage its own resources (such as memory, hard disk space, and all the peripheral devices). It tells the hardware what to do, how and when to do it. The computers in our labs are running the operating system named Microsoft Windows XP. Examples of system software are MS DOS, MS Windows, Linux. The operating system acts as a link between you and your computer hardware. It has the necessary instructions for the computer to function properly while making it easy for you to use the computer. For example, if you click on the Print command, the operating system sends the document to the printer. 2. Application Software: Application software are used after that the Operating system loads. They are used by the user for specific tasks. Examples include; Word Processor, for producing letters, documents, memos Spreadsheet, for working with numbers Database, for organizing information Web browser, for browsing websites on the internet E-mail client, for sending and receiving e-mail messages Desktop publisher, for creating booklets and brochures Accounting software, for maintaining finances St Ignatius College Girls JL Page 4 of 8
3. Networks A computer network is two or more computers connected together. They could be in the same room, in the same building, or on opposite sides of the world. There are several reasons for using a network: If you have two PCs but only one printer, the PCs can both connect up to the printer and share it. You could have a whole company full of computers but with only one printer, and everyone would be able to use it. As well as sharing things like printers, PCs on a network can also share files and data. Instead of making lots of copies of a file, like a company letter, one copy could be stored on a particular PC, and everyone could read it. To help people work together better, users can send messages to each other through their connected computers - this is called electronic mail, or email. LANs and WANs There are three main types of networks: LAN (Local Area Network): This is a small network, connecting computers spread out over a fairly small, local area - either in the same building or in a few buildings. WLAN (Wireless Local Area Network): A network in in which a mobile user can connect to a local area network (LAN) through a wireless (radio) connection. WAN (Wide Area Network): This is a larger network, connecting computers spread out over a wide area - usually around the whole country, or around the world. Connecting Computers Together LANs are connected by a system of cables that let the computers talk to each other. The computers must also have network cards installed in order to get them to connect to the network. WANs use the telephone cables (the PSDN - Public Switched Data Network), as well as satellites and other clever bits and pieces. This saves companies having to lay loads of extra cable, but it means they have to use special equipment to send their information down the phone lines. Client/server network A client/server network has one or more computers acting as a server while the other computers (i.e., clients) on the network can request services from the server. A server is the host or central computer that manages the resources on a network. A client/server network typically provides an efficient means to connect 10 or more computers together. Most client/server networks have a network administrator who is in charge of the network. A client computer is a A network operating computer that can access system is the system the resources on a network. software that organizes and coordinates the activities on a LAN. St Ignatius College Girls JL Page 5 of 8
The Internet The Internet consists of lots and lots of computers and networks all connected together by telephone lines and cables. People use it to share information with other users around the world. The Internet has three main parts:- The World Wide Web, which refers to all the web pages and websites on the internet containing information Email, which is the way in which messages can be sent over the Internet File Transfer Protocol, which is the way in which files are transferred from one computer to another over the Internet. Sometimes the phrases The Internet and The World Wide Web are used interchangeably. However, to be strictly correct, the Internet refers to all the computers and cables that make up the network, and the world wide web refers to the pages of information which are stored on those computers. The Internet is also sometimes referred to as The Information Superhighway. Intranet is a smaller, closed version of the Internet Can by accessed only by authorized persons Easily accessible via web browser An extranet is an Intranet that is partly accessible by outsiders Limited access to outsiders via web browser What You Need To access the Internet you need a modem. You also need to subscribe to an Internet Service Provider. This is a company you have to go through to get on the Internet, using a user name and password. Depending on their location, users have different options for connecting to the Internet of which; phone line, mobile phone, cable, wireless and satellite. An ISP may provide different Internet connection services of which dial-up and broadband. Internet data transfer speed is measured in bits per second (bps), kilobits per second (kbps) or megabits per second (mbps). Security For security reasons a user name (ID) and password are needed for users to identify themselves when logging on to a computer. Good password policies include: Not sharing passwords. Changing them regularly. Adequate password length. Adequate mix of letters and numbers. St Ignatius College Girls JL Page 6 of 8
Internet services for customers e-commerce is basically doing business on the Internet. Most companies have their own websites, and a lot of them allow people to do business with them this way. For example, most airline companies have a website that lets you check flight schedules, and book tickets using your credit card details. It's all done online (on the Internet) and you don't even have to get out of your chair. It is also safe, as your credit card details are encrypted as they pass over the Internet. This means they get scrambled up so that hackers cannot decode them. e-banking - Banking transactions are performed electronically without visiting the actual brick-and-mortar institution. e-government - The use of technology to enhance the access to and delivery of government services to benefit citizens, business partners and employees. Email Email can be sent over the Internet, just like in a company network. It is much, much quicker than the traditional postal system. Unlike a company network though, you can send it to anyone in the world, as long as they have access to the Internet and email software. When you want to send an email to a friend, you simply type a letter into your email software, and send it. The software sends it off down the phone line to your ISP, they forward it to your friend's ISP, which then sends it on to your friend. The next time your friend "logs on" to the Internet and checks their email, your message will be sitting waiting for them. Email is also useful for sending attachments. An attachment can be any file, e.g. a Word document, an Excel spreadsheet, a photograph that you can attach to the email and send to somebody. E-learning The delivery of a learning, training or education program by electronic means. E- learning involves the use of a computer or electronic device (e.g. a mobile phone) in some way to provide training, educational or learning material. Some of its features: flexible learning time flexible learning location multimedia learning experience cost effectiveness. St Ignatius College Girls JL Page 7 of 8
Tele-working Tele-working refers to people working at home connected to the rest of the organization via a computer network. Communication is via email or the telephone. This arrangement has advantages and disadvantages to both the employer and the employee. Some of the advantages of tele-working 1. Reduced or zero commuting time. This saves time (and money) for the employee and reduces environmental overheads, as less commuting means less car pollution. It means that the employee does not arrive at work already stressed from car jams or late train connections. 2. Greater ability to focus on one task: As there are fewer interruptions from low priority phone calls, there is a greater ability to concentrate and focus. 3. Flexible schedules: In many cases, as long as the job gets done, it does not matter when the job gets done. This means there is time for other activities, such as picking up the kids from school. It also means that work can be finished in the evening if required. If it is a beautiful day, why not take advantage of the weather, and finish your work later. 4. Reduced office desk space requirements: The cost of Office space can be very high and tele-working can help to reduce these costs if a proportion of the staff works at home. "Hot Desking" is a term used to indicate that people do not have a desk dedicated to their exclusive use. People simply sit at any desk and log on to the networked computers using their own ID, which will allow them to uniquely access their own work stored within the computer system. Hot Desking is popular where staff spends a proportion of their time working at home, or at sites outside the main office complex. Some of the disadvantages of tele-working 1. Lack of human contact: Many people site this as the single biggest factor when switching from a regular office job, to tele-working. In fact many companies now arrange company gossip networks, just so that people can keep in touch. 2. Negative impact on teamwork: If you never see the rest of the team it is hard to feel part of the team. Video links and occasional get-together meetings may compensate. 3. Self-discipline: It can take a lot to work from home and remain focused on work. It is all very well saying 'I will take the afternoon off and work this evening', but come the evening you may not feel like working. 4. Possible Employee Exploitation: If workers are isolated from each other there is the possibility for companies to take advantage. Some large companies using tele-working restrict trade union activity (or if they can, ban it altogether). St Ignatius College Girls JL Page 8 of 8