Computer hardware servicing 102 chapter3 PC Overview
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The document provides an overview of the key components inside a personal computer. It discusses the system unit which houses the main components including the motherboard, processor, memory, video card, sound card, ports, drive bays, and power supply. The processor executes instructions to perform tasks while the memory temporarily stores data and instructions. Other components like the hard disk, video card, and monitor allow for permanent storage, graphics processing, and visual output.
Computer hardware servicing 102 chapter3 PC Overview
- 2. COMPUTER Y our computer looks like a box accompanied by a screen, keyboard, and mouse, but there’s a lot hidden inside that box.
- 3. What’s Inside Your Computer? What is the system unit? Box-like case containing electronic components used to process data. It is the case that holds the computer’s critical components.
- 4. Motherboard Main circuit board in system unit Contains the important components of the computer. Also called system board
- 5. The System Unit What are common components inside the system unit? power supply Processor Memory Adapter cards drive bays Sound card Video card processor ports memory Ports Drive bays Power supply video card sound card
- 6. A computer with nothing but a processor, memory, and power supply isn’t very useful because it can’t communicate with you or with other computers. Each of the other core components exist to either store information or let the processor communicate: ✦ Bus — Connects the processor to the memory, I/O channels, and display. ✦ I/O channels — Connects the bus (and therefore the processor) to the disk, keyboard, mouse, network, and any other devices ✦ Disk — Stores large amounts of information, retaining that information even when the power is off. ✦ Display — Draws images and characters on a monitor, giving programs a way to output in a way you can read
- 8. Processor and Instructions A special signal inside the computer, called the clock signal (or just the clock), synchronizes components in the computer, providing the cadence to which the entire assembly marches. The clock times every action by the processor and sets the synchronization requirements for all the other components. Every instruction executed by the processor starts on the beginning of a clock cycle and lasts for one or more clock cycles.
- 9. Executing instructions is the work the processor does. The tasks the processor carries out — tracking actions you take with the keyboard, joystick, or mouse; rendering and presenting the graphics on the display; moving information from disk to memory and back; communicating with your network; running your desktop accessories; or keeping the current print job going — each require some number of instructions to complete. The number of instructions required divided by the number of instructions per second determines how long each task takes.
- 10. Buses ✦ Front side bus — The front side bus (FSB) connects the processor to a chipset, one or two chips responsible for joining all the different buses together. The two major processor manufacturers, Intel and AMD, each use a different design for the FSB. Because of that, you can’t directly plug an Intel chip into an AMD socket, and vice versa. ✦ Memory bus — The memory bus connects the chipset to the memory modules. ✦ Graphics bus — All high performance graphics chips interface to the chipset through an Accelerated Graphics Port (AGP) bus. ✦ Expansion bus — The expansion bus connects adapter cards and I/O buses to the chipset.
- 12. Memory RAM is our working memory storage. All the data, which the PC uses and works with during operation, are stored here.
- 13. The memory module operates the individual chips in parallel. The key parameters defining a memory module are these: ✦ Capacity — A memory module holds a specified number of bytes, with one address corresponding to each byte. The capacity of a memory module is the number of bytes it holds. ✦ Width — A memory module built from multiple chips in parallel can be as wide as the module designer wants, with the width being the number of bits (8 to a byte) that the memory accesses at one time. Common widths for memory modules used in current computers are 32, 36, 64, and 72 bits, depending on whether or not your computer checks data transfers from memory for reliability. ✦ Access time — There is a minimum interval the memory requires from the time it’s told to read a number to the time when the number is available for the processor to use. Smaller access times mean the memory is faster and more expensive, but faster memory does not make your computer run faster. ✦ Cycle time — Another interval, the cycle time, specifies the minimum time from one memory operation to the next. The memory requires a small delay for it to recover between when it transfers data on the bus and when it starts the next operation. The cycle time is the access time plus that small recovery delay.
- 14. Hard Disk is the most popular storage device used to store various kinds of data in most computers. is a data storage device used for storing and retrieving digital information using rapidly rotating disks. An HDD retains its data even when powered off. It is the computer’s main storage media device that permanently stores all data on the computer. The hard drive was first introduced on September 13, 1956 and consists of one or more hard drive platters inside of air sealed casing.
- 15. Aside from its capacity, the important characteristics of a disk all relate to performance. The key disk performance characteristics are: ✦ Rotation rate — Rotation rate is the speed at which the disk platters turn under the heads, measured in revolutions per minute (RPM). ✦ Access time — Access time is how long it takes from when the processor requests data from the disk until it’s available. ✦ Sustained transfer rate — The data transfer rate a disk can sustain is the rate at which the combination of disk and I/O channel can, over period of time, maintain a data transfer.
- 17. Video cards and Monitors Monitor device connected to a computer that displays information on a screen. Video Card the electronic components required to generate a video signal that is sent to the video display through a cable. The video adapter is usually located either on the computer's main system board or on an expansion board.
- 18. Pixel A pixel (short for “picture element”) is one of thousands of tiny spots in a grid on a display screen or printed sheet. These spots, or blocks, are individually colored in order to show images on computer screens, and represent the smallest elements that may be manipulated to create graphics.
- 19. Resolution the clarity or fineness of detail attained by a monitor or a printer in producing an image. In relation to computer monitors, resolution is defined as the number of pixels per unit of measurement (such as inch or centimeter) on a video display. The word resolution is commonly used to denote the total number of pixels displayed horizontally or vertically on the video display.