TOPIC 5 PC or handheld computer hardware components

TOPIC 5 PC or handheld computer hardware components

Subject Outcomes Describe the characteristics of personal computer hardware components Compare and select personal computer hardware components Test personal computer hardware components.

Unit 1 – The characteristics of personal computer hardware components Learning Outcomes Identify the purpose of a component using examples as well as providing an outline of its functions. Outline the operating principles of a component. Outline the relationship between components by describing the interaction between them. Describe the resources required for the installation to ensure that they are available at the time of installation and are in working order. NB!! Each component has a specific function and is easy to replace. Understanding the relationship between components makes troubleshooting easier.

Identifying the purpose of a component The component of a PC consist of input/output devices, printed circuit boards and a CPU. The case is usually supplied with a power supply unit (PSU). The function of the PSU is to supply power to all the other components of the PC. A power cable is plugged into the PSU, which then distributes the power. A cooling fan is the only moving part of the PSU.

Input /Output devices A device that provides input to the computer is called Input device which is in two forms; • • Data such as numbers, characters or pictures Control information, such as programmes and commands. A device that presents data to the external world is an output device. Both Input /Output devices can be divided into two categories being storage devices and non-storage devices. Storage devices are both input and output devices. Some non-storage devices are only used for input, and some only used for output, example is Touch-screen monitors.

Input /Output devices… Some applications for monitor as an input device are; • Some automatic teller machines • Self-service ticket dispensers • Information screens in shopping complexes • Monitors connected to some point-of-sale equipment Keyboards allow input of characters. Printers are used for output. It consists of characters (both alphabetic and numeric and pictures)

Printed circuit boards A printed circuit board is a flat board on which chips and other electronic components are mounted. They are made of non-conducting material, such as plastic or fibreglass. To avoid damage, a PCB should always be held by the edges and protected from dirt and static electricity. Examples of printed circuit boards are; • the main board • sound cards • video display adapters • network and communication cards

Printed circuit boards… The main board is also called the motherboard. This is because it houses other cards – they are all plugged into the main board. The motherboard contains the following; • processor and memory • BIOS and CMOS • I/O ports (for devices such as keyboards, mouse and printer) BIOS stands for Basic Input Output System CMOS stands for Complementary Metal-Oxide Semiconductor • CMOS store information such as the types of disks available, settings for time and date of the system clock, power management features.

Printed circuit boards… I/O ports on the motherboard may vary, depending on factors such as the make and model. Sound cards provide ports for audio input and output. Video display adapters, also called display cards, control output to a PC monitor. If your PC is to be used as a gaming station, it will probably need a specialized video adapter.

Central Processing Unit is the heart of the computer. This is where all computing, or processing, takes place. Apart from performing all the arithmetic and logic operations, the CPU also controls all other functions on the PC. CPU controls the following; • the instruction set (this is for commands such as move, store or add) • arithmetic logic unit (this is where all calculations are and logic decisions are made) • data paths (these are the route that the data takes place when being moved from one area to another) • registers (they are used for temporary storage of data, addresses and commands) • Cache (mainly pronounced ‘cash’. This is data where that may be used again and again are stored). Access to cache is hundreds of times faster than access to a storage device or RAM

CPU continued… Memory, in the form of chips on the motherboard, is a temporary storage area for data and programmes. The memory chips are called primary memory. Secondary memory or permanent memory, are bulk storage devices such as disks, tapes and compact disks. Major differences between Primary and Secondary memory are; • Access to primary memory is fast. • Primary memory requires electricity to maintain its contents. • Primary memory is used for temporary storage.

CPU continued… Memory is commonly called RAM, an acronym for random access memory. RAM comes in two forms ; • DRAM – dynamic random access memory (it requires constant refreshing) • SRAM – static random access memory (it does not require constant refreshing)

Relationship between components Process flow 1. PC is switched on, then power flows through the circuit, check contents of the CMOS 2. CPU then checks the I/O devices for an operating system such as Windows XP/ Linux / Mac OS. 3. Once Operating system has been found, the CPU allocates an area in primary memory for it to be loaded. 4. When you start an application programme on your PC, a request is sent to the PC for space to load the programme. 5. When the programme wants data from the I/O device, CPU must first decide if there is enough memory to hold the data.

Compare the performance measures of components Speed is one the main measures of performance for computer components. Capacity is another important measure. Other considerations are; • Cost of purchase • Expected useful life of the component • Levels of support required • Ease of installation • Remote diagnostics • Mean Time Between Failures (MTBF)

Unit 3 – Test personal Computer hardware components Testing in a computer environment is a constant activity. New software, new devices and new components are being introduced every day. Tests and testing will vary, depending on the device or component being tested. All tests results are either displayed as output to the monitor or are printed to a printer. Benchmark testing is done to establish a base for comparing components from different manufacturers.