Prof. Dr. M. H. Assal AS 26/10/2014
Computer hardware is the collection of physical elements that comprise a computer system Computer hardware can be classified as following: o Input devices o Output devices o System case o Storage Devices o Video Controllers 2
The Keyboard The Mouse Pens/Styluses Touchscreen Game Controller Barcode Image Scanner and OCR Biometric Readers Microphone and Speech Recognition Digital Camera 3
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The mouse is the most common pointing device for a desktop computer. Mouse Techniques 1. Pointing 2. Clicking 3. Double-clicking 4. Dragging 5. Right-clicking 6
Many devices today, including some desktop computers and many tablet computers and mobile devices, can accept pen input. 7
Touch screens allow the user to touch the screen with his or her finger to select commands or otherwise provide input to the computer associated with the touch screen. 8
A game controller is a device used with games or entertainment systems to provide input to a video game, typically to control an object or character in the game. 9
A barcode is an optical code that represents data with bars of varying widths or heights. 10
A scanner, more officially called an optical scanner, captures an image of an object (usually a flat object, such as a printed document, photograph, or drawing) in digital form, and then transfers that data to a computer. 11
Scanning Quality and Resolution o The quality of scanned images is indicated by optical resolution. o Resolution usually measured in the number of dots per inch (DPI). o Typical flatbed scanner has a resolution of 300 DPI. o A higher resolution results in a better image but also results in a larger file size. 12
o o Optical character recognition (OCR) refers to the ability of a computer to recognize text characters printed on a document. The characters are read by a compatible scanning device, such as a flatbed scanner and then OCR software is used to identify each character and convert it to editable text. 13
Biometric readers are used to read biometric data about a person so that the individual s identity can be verified based on a particular unique physiological characteristic (such as a fingerprint or a face) or personal trait (such as a voice or a signature). 14
Microphone: is a device used for capturing sound as electrical signals. o Microphones can accept auditory input. o A microphone requires a sound card in the PC. A Sound card can digitize analog sound signals(mic input).also it converts digital sound signals to analog form(speaker output). With speech recognition software, you can use your microphone to dictate text, navigate programs, and choose commands. Speech recognition is the translation of spoken words into text. It is also known as "automatic speech recognition", "ASR. 15
PC video cameras digitize full-motion images. Digital cameras capture still images. 16
Monitors Sound Systems Printers 17
Cathode Ray Tube (CRT) o The first computer monitors used cathode ray tubes (CRT) until the early 1980s. o The monitors were monochrome, flickered and the image quality was poor. o In 1981, IBM introduced the Color Graphics Adapter. 18
A Liquid Crystal Display (LCD) uses charged liquid crystals located between two sheets of clear material (usually glass or plastic) to light up the appropriate pixels to form the image on the screen. 19
LED (light emitting diode) technology is another flat-panel technology commonly used with consumer products, such as alarm clocks, Christmas lights, car headlights, and more., Another form of LED OLED may eventually replace LCD technology entirely. 20
A Wearable Display (such as the eyeglasses-based display) projects the image from a mobile device (usually a mobile phone or portable digital media player) to a display screen built into the glasses. 21
A video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. 22
Size: is the diagonal measurement of its face, in inches. Resolution: is the number of pixels on the screen, expressed as a matrix. o o Half HD (720p) monitors has resolution of 1280x720 Full HD (1080) monitors has resolution of 1920x1080 Refresh rate: is the number of times each second that the electron guns scan the screen's pixels. o o o Refresh rate is measured in Hertz (Hz), or cycles per second. Look for a refresh rate of 72 Hz or higher. A slower rate may cause eyestrain. Dot pitch: is the distance between the phosphor dots that make up a single pixel. 23
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Printer categories Printers produce images through either impact or nonimpact technologies. Impact ex. a dot-matrix printer Nonimpact ex. laser printers and ink-jet printers 25
Image Quality Measured in dots per inch (dpi). Most printers produce 300 1200 dpi. Speed Measured in pages per minute (ppm) or characters per second (cps). Initial Cost Consumer printers cost $250 or less, but professional printers can cost thousands of dollars. Cost of operation This refers to the cost of supplies used by the printer. 26
A Dot Matrix Printer or impact matrix printer is a type of computer printer with a print head that runs back and forth, or in an up and down motion, on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like the print mechanism on a typewriter. 27
Ink-jet printers form images by spraying tiny drops liquid ink from one or more ink cartridges onto the page, one printed line at a time. 28
Laser printers are the standard for business documents and come in both personal and network versions; they are also available as both color and black-and-white printers. 29
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Storage Devices are the data storage devices that are used in the computers to store the data. The computer has many types of data storage devices. They can be classified as: o Removable data Storage Devices USB Flash Drives External or Portable Hard Drives Memory Cards Optical Discs (Blu-ray, DVDs. CDs) o Non-removable data Storage Devices Internal Hard Drives Solid State Drives 31
Floppy Discs is a data storage medium that is composed of a disk of thin, flexible floppy) magnetic storage medium encased in a rectangular plastic shell. Magnetic tapes o It has been used for data storage for over 50 years. o Tape can be substantially less expensive than disk or other data storage options. o Modern usage is primarily as a high capacity medium for backups and archives. o In the other side, Writing and retrieving data is slow. 32
Hard Disk Drive (HDD) o It is the device used to store large amounts of digital information in computers and related equipment like ipods and games consoles. o Hard disk drives are used to store operating systems, application software and working data. o However, Hard disk drives may not be suitable for applications which need portability. 33
Portable hard discs o Useful for transferring data (programs, pictures, etc.) between computers. o Has Large storage capacity (relative to other storage devices such as floppy discs). o Hard drives have to be handled quite carefully. o More expensive than other forms of removable media. 34
Solid state storage devices o Widely used as removable storage. o They are more robust than other forms of storage. o Examples: Solid State Drives Memory sticks. Flash memory cards 35
Optical Storage Devices o o CD-ROMs are popularly used to distribute computer software, including video games and multimedia applications, though any data can be stored (up to the capacity limit of a disc). DVD is an optical disc storage format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions. 36
Disk formatting is the process of preparing a data storage device such as a hard disk drive, solid-state drive, floppy disk or USB flash drive for initial use. Formatting a disk means configuring the disk with a file system so that Windows can store information on the disk. Hard disks in new computers running Windows are already formatted. If you purchase an additional hard disk to expand the storage of your computer, you might need to format it. A. Track (The circular rings) B. Sector (Each Track has fixed # of Sectors) C. Block D. Cluster 37
A computer case (also known as a "computer chassis or simply "case") is the enclosure that contains most of the components of a computer (usually excluding the display, keyboard and mouse). A computer case is sometimes incorrectly referred to a CPU referring to a component housed within the case. 38
Video card (also called a video adapter, display card, graphics card, graphics board, display adapter or graphics adapter) is an expansion card, which generates a feed of output images to a display. 39