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Introduction to Hardware and software This handout provides you with a brief historical overview of the development of computers from Mainframes to the Personal Computer that we are familiar with today. It then moves on to introduce you to the basic terms that are commonly used when discussing PCs. It is important that you understand these terms as they will be frequently referred to in the following handouts. Key Functions of a PC Before looking at the components of Personal Computers (PCs), it is worth taking a few moments to consider the key functions that are performed by a computer: Input – Entry of raw data; for example, typing names and addresses on a keyboard or transmitting a picture from a digital camera. Processing – Manipulation of the raw data to produce useful information, the key purpose of a computer; for example, sorting or indexing the names and addresses or adding effects to the picture. Output – Transformation of the data into information, perhaps in a non-computerised format; for example, printing mailing labels from a database or displaying the picture in a brochure. Storage – Retention of the data until it is needed; for example, filing names and addresses in a database or archiving the picture in an online library. With a basic understanding of these key functions, the role of each of the components of a PC becomes much clearer. Systems components A PC system comprises various components that interact together; these components can be split into two distinct categories: hardware and software. The hardware can best be described as the physical components such as the monitor, case, hard drive and RAM. Software is less tangible, in that it is a programme consisting of a set of instructions that allow the PC to perform tasks. The main classes of software are: An Operating system is designed to control the functions of the PC and provide the user with the ability to interact with the hardware. Applications are programmes that are written to perform specific functions such as wordprocessing, image manipulation or e-mailing. Device Drives are programs designed to allow the operating system to fully utilise the abilities of a hardware device. Hardware components Before you continue on to the technical aspects of the course you must have a sound knowledge of the basic components that make up a computer system. The diagram below shows some of the common components that make up the computer system. Monitor Printer System case Modem Mouse Keyboard Figure 1 common hardware components System case - contains the components of the computer, such as the motherboard, CPU and expansion cards. System cases design fall in to three main styles: Desktop cases are designed to sit horizontally on a desktop. There is also a special variety of desktop case known as low-profile or slim line case that reduces the vertical height of the systems unit. Tower cases are designed to stand vertically. Mini and mid towers are short towers designed to take up less vertical space than a full size case. Full-sized cases tend to be used by servers, whereas the mini and mid towers tend to be used by PCs. Note: A server is a computer, which is used to manage network resources and provide centralised control. Portable systems such as laptops or notebooks combine the system unit and input/output devices into a single lightweight unit which allows people to use their computers while they are away from their desks. Desktop Tower Notebook Figure 2 computer case styles Parts of the Case Cover – The case has a cover which is removed by either undoing the screws at the back, or pressing together clips that release it. Chassis or enclosure – The chassis is the metal frame that houses the main components of the PC. Front Panel – The front panel provides access to the floppy and CD, a power on/off switch, a reset switch, and Light Emitting Diodes (LEDs) to indicate drive operation. The front cover can be removed but may require the case cover to be removed first in order to access the screws or clips that secure it. Rear Panel – The rear panel has slots through which interface card connectors appear. These slots should either by covered by an interface card or a metal strip known as a blanking plate. Drive Bays – A drive bay is an area that is designed to accommodate drive devices such as Hard Disk Drive (HDD), floppy drive or CD ROM/DVD. An ATX Mini Tower system case commonly has two drive bays which are known as the 3 ½ and 5 ¼ inch drive bays. These dimensions relate to the width of the disk media these bays were originally designed to accommodate and not the width of the bays themselves. The 3 ½ inch drive bay is commonly used to secure the HDDs and floppy disk drives. While the 5 ¼ inch drive bay is used to securer devices such as a CD ROM. Fixed storage devices - an example of a fixed storage device would be a hard disk that is secured to the internal chassis of the system case. Hard drives are made up of a collection of magnetic disks attached to a spindle. Hard disks are non volatile storage, which means that the data stored on a hard disk is retained even after the power is switched off. Figure 3 a hard disk drive Removable media drive - Most PCs have one or more forms of removable storage devices. Removable storage devices allow data to be stored and transferred easily. There are three main types of removable storage devices, magnetic such as floppy disks and tape drives; optical storage such as CDs and DVDs; and solid-state storage, such as flash memory cards and memory sticks or keys. Power supplies - convert the high voltage Alternating Current (AC) to the low voltage Direct Current (DC) required by computer circuitry. The power supply in a conventional desktop system is designed to convert the 240-volt AC current into 3.3v, 5v and 12v DC current. Figure 4 Power Supply Unit The motherboard - is a printed circuit board which contains the main structures which make up a system. The Diagram below shows a typical layout of an ATX motherboard. Parallel Port PCI Slots USB Port PS2 Port AGP Slot CPU Socket CNR Slot Power Connector RAM Sockets Chipset Battery IDE Controllers Floppy drive Controller Figure 5 typical ATX motherboard layout. The Central Processing Unit (CPU), or processor, process data, and sends the processed data to the appropriate data storage or output device. Figure 6 The Central Processing Unit (CPU) Memory - there are two main types of memory: Random Access Memory (RAM) and Read Only Memory (ROM). When people talk about memory, they are usually referring to RAM. Program data and instructions are copied from the hard drive to the RAM to allow the data to be accessed quickly by the CPU. RAM is volatile memory; this means that data is lost when the power is turned off. Figure 7 Random Access Memory (RAM) Read only memory (ROM) is a type of memory that can only be read from and provides permanent storage for data and instructions. An example of ROM is the Basic Input/Output System (BIOS) which contains a pre programmed set of instructions which are required during the boot process. Figure 8 Basic Input/Output System (BIOS) Chip The I/O expansion slots enable your CPU to communicate with peripheral devices. The bus and its associated expansion slots are needed because basic systems cannot possibly satisfy all the needs of all the people who buy them. The I/O bus enables you to add devices to your computer to expand its capabilities. The most basic computer components, such as sound cards and video cards, can be plugged into expansion slots. Figure 9 an expansion card Input devices such as the keyboard and mouse, are used to issue commands and enter information into your PC. These are not the only devices that may be used to input data; other devices such as scanners, microphones or barcode scanners are commonly used. Output devices such as monitors, printers and speakers are commonly used with PCs. Output devices are capable of representing information that has been generated within the computer in a format that humans can understand. At this point it is advisable for you to complete Lab 1.1 Identifying Components of a Computer System Summary This module you have dealt with the basic concepts of hardware and software. It is important that you have a sound knowledge of these basic concepts as you will be dealing with them in more detail later on in the course. Lab 1.1 Identifying the Components of a Computer System Objectives Upon completion of this lab you will be able to identify the various components that make up a computer system. Equipment A computer system. Introduction The ability to identify the components that are used as part of a computer system provides you with the basic knowledge required to enable you to understand the concepts and theories introduced later in the course. Task 1 In this task you are going to determine the components that make up your computer system. Look at your systems case; identify the style of case that you are using as part of your system? (Enter the details in the space provided below.) What types of output devices are attached to your computer system? (Enter the details below) Identify the additional components that make up your system? (Enter the details below) Summary In this Lab you have identified the basic components of a computer system.