In this article, let see basic and primary computer hardware devices are addressed with a focus on their use and functionality of the computer.
Introduction to Computer Hardware
Computer hardware is one of the two main parts of the computer. This is the collection of physical parts of a computer system. This includes the computer housing, the monitor, the keyboard, and the mouse. It also includes all parts of the computer case, such as the hard disk drive, motherboard, video card, and many more. The computer hardware is what you can touch physically. The computer can not work without material. Some hardware components are easy to recognize, such as the computer housing, keyboard, and monitor, while some are inside the computer housing. Most hardware devices work as input or output devices that are typically housed outside the main computer chassis.
Generally, the concept of hardware includes computer components, physical and tangible parts of the computer, that is, electrical, electronic, and mechanical parts that include a computer. The basic operating principle is given in the picture below:
Operating principle: The data is entered into a computer via input devices, and then processed and stored in a system unit, and are finally displayed by the output device.
Input and output function
In IT, the input/output (I / O) refers to the communication between an information processing system such as the computer and the external world possibly human or another information processing machine. The inputs are the signals or data received by the system and the outputs are the signals or data that sent it. Keyboards and mouse are considered computer input devices, while the monitor and printers are considered to output devices of a computer. Computer communication devices such as modems and network cards generally serve as input and output. Note that the designation of a device as input or output depends on the point of view. The mice and keyboards take physical entry movements that the human user generates and convert them to a signal a computer can understand. The output of these devices is entered for the computer. Similarly, printers and monitors take as input signals than a computer output. They then convert these signals to representations that human users can see or read.
Input devices
Input devices allow the user to enter information into the system or control how it works. Most personal computers have a mouse and keypad, but laptop systems usually use a touchpad instead of a mouse. Other entry devices include webcams, microphones, joysticks, and image scanners.
Keyboard
The keypad is the most commonly used input device and is an adaptation of the typewriter.
The keypad is used for data entry and transmitting controls. They can also be wired or wireless.
Computer keypads contain several types of keys to enter data and emission commands. A keyboard has a digital buffer and additional numeric function keys (F1 - F12). The function keys provide special functions depending on the software you use. A numeric keypad is a
A QWERTY keyboard is the layout of the standard typewriter keypad, used for computer keyboards. This is the most frequently used input device for all computers. The keyboard provides a set of alphabetic, digital, punctuation, symbol, and control keys. Some of the key keys and their keyboard features include:
ENTER or RETURN - Moves the cursor down one line and to the left margin.
DELETE or DELETE - Deletes the character at the cursor and/or the characters to the right of the cursor and all highlighted (or selected) text.
BKSP or BACKSPACE - Deletes the character to the left of the cursor and all highlighted text.
SPACE BAR - Moves the cursor right one space at a time. SHIFT KEY - Use the upper case keys to type upper case letters and to type the top character on keys with two characters on them.
CAPSLOCK - Locks the keypad to type in uppercase letters (an indicator lights up when the caps lock is on).
TAB - Moves cursor right five spaces.
ESC or ESCAPE - Cancels a menu or dialog, command, or operation.
ARROW KEYS - Moves the cursor in the document without changing the text.
FUNCTION KEYS or F KEYS - Access commands alone or in combination with the three command keys; SHIFT, CTRL, and ALT.
Command keys or special keys: Command keys normally do nothing on their own but work in combination with other keys. The Ctrl or Ctrl key is often used to access commands. It is pressed in combination with other keys, acts as a shortcut to execute commands and to select commands from drop-down menus. The Alternative or Alt key is often used to access menus. The Shift key is used to type CAPITAL LETTERS.
NumLock - This key toggles the right keyboard between entering numbers and using it as cursor keys.
Previous page (PgUp) and Next page (PgDn). These keys move the cursor to the previous screen (PgUp) or to the next screen (PgDn).
Disks
A disk is a round plate on which data can be encoded. There are two main types of discs: magnetic discs and optical discs. Magnetic discs allow you to save and erase data an unlimited number of times. Examples of magnetic disks are floppy disks (floppy disks), hard disks, and flash disks. Hard drives are placed inside the computer and were originally called "fixed drives" or "Winchesters".
Hard drives are measured in gigabyte (GB), terabyte (TB), petabyte (PB), exabyte (EB), etc. The relationships between these units are:
- 1 TB = = 1000 or 1024 GB
- 1 Po = = 1000 or 1024 TB
- 1 EB = = 1000 or 1024 PB
Optical discs record data by burning pinholes on the surface of the disc with a laser. To read the disc, another laser beam illuminates the disc and detects holes by changes in the reflection pattern. Optical discs come in three basic forms: CD-ROM (read-only), WORM (write-once, multi-read), and erasable optical disc (EO disc). Note that CD-ROMs (Compact Disk - Read Only Memory)) and WORM disks are not erasable while EO disks can be read, written, and erased like magnetic disks. The machine that reads or writes information to a disk is called a disk drive.
Optical disc
CD-R (Compact Disk-Recordable Drive) is a type of disk drive that allows you to create CD-ROMs and audio CDs. To create CD-ROMs and audio CDs, you will need not only a CD-R drive but also a CD-R software package. CD-RW DISK (CD-ReWritable disk) is a type of CD disc that allows you to write to it in multiple sessions. One of the problems with CD-R discs is that you can only write to them once. The capacity of the most widely available CD format is expressed in 74 minutes or 650 MB.
Mouse
The mouse controls the pointer on your computer screen, which is housed in a housing the size of a palm. When you move it on your desktop, the corresponding arrow, commonly known as a pointer, moves on the computer screen. Using the mouse can eliminate many keystrokes. The flashing bar, called the cursor, is where work will take place on the computer screen.
To move the cursor with the mouse, place the pointer where you want the cursor to appear and click the mouse. The ordinary mouse has two buttons: the left one is used to select objects and text, and the right one is used to access menus. Sometimes a mouse comes with a middle button or scroll wheel between the left and right buttons.
In particular, the mouse is important for graphical user interfaces (GUIs) because you can just point and click. You can never do wrong by right-clicking on something. The different mouse operations include:
- Point - Move the mouse so that the mouse pointer rests on the required object such as an icon, the name of a menu, a button in a dialog box, a character in a document, a shape in an image, etc. Click - Press and release the left mouse button. One click selects an object, a command, or a program.
- Double-click - A double-click is a rapid succession of two clicks in the same place.
- Dragging - Dragging allows you to move items in windows or on the desktop. Point at an object, press and hold a mouse button, move the mouse to a new position, and release the mouse button. (is sometimes called drag and drop).
So, generally, a mouse is an input device that makes it easier to work with the graphical user interface (GUI). The mouse transmits the movements of the hand and the screen displays the movements of the cursor (mouse pointer). They are divided into mechanical and optical (concerning a transfer movement), and wired and wireless (concerning connection). The trackball, unlike a mouse, is not movable. Hand movements are transmitted to the screen by rolling the ball on the top of the device.
Scanners
The optical scanner looks like a small copier and acts as an input device. They work by reading light reflected from the surface of an object such as a photograph, numbers, or printed materials such as text. The scanner comes with software that allows it to have control over the scanned image.
Scanners allow you to transfer images, photographs, or images to your computer. A scanner "scans" the image top to bottom, one line at a time, and transfers it to the computer as a series of bits or as a bitmap. With optical character recognition (OCR) software, you can convert printed documents into text that can be used in your word processor. Typically, the scanner is used to load data (image, text, etc.) from printed material into a computer. The result of scanning is an image, but with special programs, if we scan the text, we can get a text accordingly. The software used to recognize text from an image is called a text recognition tool.
Other types of input devices include:
The touchpad is used for the transmission of hand movement, but unlike working with a mouse, the user is the one who determines the cursor position by touching the touchpad.
Lightpen allows handwriting on the screen and can be used as a mouse. It requires an appropriate type of monitor.
The joystick is mainly used in computer games. Unlike a mouse, it has many buttons that allow you to control game objects.
The microphone is a device that converts sound into an electrical signal, which can be stored on a computer. It is mainly used for sound recording, communication between players in online games, in combination with a web camera in a video conference, for converting voice to text on a computer (speech to text processing ( for example, text files or e-mails), etc.
The webcam is a camera that stores the video signal in a format suitable for video transfer over the Internet in real-time.
The digital camera, unlike the analog, stores photographs in numerical format. It can be directly connected to a computer and photographs can be downloaded. The quality of the photos is expressed in megapixels. More megapixels mean better quality of photography; however, more memory is occupied.
Output Devices
Output devices display information in human-readable form. These devices can include monitors, printers, speakers, projectors, etc.
CRT Monitor
The monitor is an output device that displays information on the screen as you type. Monitors come in many different types, sizes, and color screens. It connects to the computer's video output called Video Display Unit (VDU). Common monitor interfaces are cathode ray tube (CRT) and flat-panel liquid crystal display (LCD).
Flat screens are small and do not flicker, they consume very little power, so they are ideal for laptops.
Compared with CRT monitors, LCD monitors use less electric power, do not emit radiation, and their price is higher, but due to smaller dimensions, more attractive design, and good quality image, they push CRT monitors out of the market. Monitor size is expressed as the diagonal screen size and measured in inches (''). Image quality is expressed by the notion of the resolution, which is several horizontal and vertical dots (pixels) (eg 1920x1080).
Printers
HP Printer EPSON CANON
A printer is a device designed to print your computer-generated documents onto paper. Printers vary in quality, speed, graphics capabilities, fonts, and even paper usage. Some printers print one character at a time; some print one line or an entire page at a time. Data can be sent to a printer through a serial or parallel port.
The three most popular types of printers are dot-matrix, inkjet (bubble jet), and laser printers. Printers are also categorized into impact and non-impact. The impact printer produces characters by using a mechanical print head which strikes the ink ribbon against the surface of the paper, leaving an impression of the character on the paper. Dot-matrix printer is a type of impact printer. Line printers produce line-by-line output and can print in a range of 1200 to 6000 lines per minute. The most common line printer is the impact type. Non-impact printers don't use a typing device to produce characters on paper, and because these printers don't hammer against the paper, they are much quieter. Examples in this category include inkjet printers, thermal printers, and laser printers.
Printers can also be distinguished between the local printer (connected directly to the computer) and the network printer (connected directly to the network using a network card). Dot-matrix printers are the oldest, with the lowest print price per paper, they are slow, make a lot of noise when printing, and are mostly suitable for printing text. Laser printers are similar to photocopying devices in terms of technology. They have exceptional print quality, speed, and silence. The disadvantages of laser printers are their high price and the high price of toners.
Inkjet printers have high print quality (a little lower than laser printers), they are quiet when printing, and have a low initial investment. The price of ink, especially color ink, can cost as much as the printer itself. Printing technology is based on dispersing the ink from the container onto the paper. The plotter is used for printing large drawings (up to A0). They are extremely expensive and used only for professional purposes, such as in design companies for printing technical drawings (blueprints). The thermal printer, as the name suggests, leaves an impression on the paper by using heat. They use heat-sensitive paper, have small dimensions; are quiet when printed, and are relatively inexpensive. They are generally used for printing receipts and hence are referred to as POS printers (sales printers). In addition, they are used as printers for calculators and, due to their small dimensions, as portable printers.
Projectors
The projector is a device used to project a computer image or other images from independent devices, such as DVD players, Blue-ray players, etc. on a canvas or a wall
Input/Output Devices
Storage devices, due to the need to write and read data, are classified as input/output devices. The touch screen (ie. Other devices that perform both I / O operations include CDs, DVDs, and flash disks.
Common Input/Output Ports
Universal Serial Bus (USB) is used to connect various devices (mouse, keyboard, USB key). The serial port is used for example to connect a mouse (labeled COM1 or COM2). The parallel port is used to connect a local printer (LPT1 or LPT2). The network port is used to connect computers to a network.