Hardware Components (input, output, memory & storage)

Hardware Components

1.       Input Hardware

2.       Output Hardware

3.       Processing Hardware

4.       Storage Hardware

5.       Communication Hardware

6.       Others

I. Input Hardware

Before a computer can process your data, you need some method to input the data into the machine. The device you use will depend on what form this data takes (be it text, sound, artwork, etc.).Consist of devices that take data and programs from the computer can process.

I.1. Text Input devices

The input of text into a computer system is one of the most common and important channels for humans to interact with a system.

a)      Keyboard

o   Used to enter text information into the computer. Used to type commands directing the computer to perform certain actions. Commands are typically chosen from an on-screen menu using a mouse, but there are often keyboard shortcuts for giving these same commands.

In addition...

o   keys of the main keyboard

used for typing text

o   numeric keypad

 for entering numerical data efficiently

o   editing keys

 used in text editing operations

Return/Enter · Backspace · Insert · Delete · Tab · Space bar

o   function keys

 to easily invoke certain program functions

F1 – F12 Function Key Usage

F1 Help. Click F1 Key can load the help file of the program.

F2 Rename. Select a folder or file, click F2 to rename it.

F3 Search. On desktop, click F3 to load the search form.

F4 In Internet Explorer, click F4 will list the URL Address field.

F5 Refresh. Use it to refresh the web page in Internet Explorer.

F6 In Internet Explorer, click F6 will jump to address bar.

F7 It can be used to insert ^C in command prompt.

F8 When windows startup, it can load the startup menu.

F9 In Windows Media Player, it can increase the volumn.

F10 In Windows Media Player, it can decrease the volumn.

F11 In Internet Explorer, click F11 will switch to Full Screen mode.

F12 In MS-Word, it will show out the “Save-As” dialog.

Laptop computers, which don’t have room for large keyboards

Often include a “fn” key so that other keys can perform double duty (such as having a numeric keypad function embedded within the main keyboard keys).

b)      Terminal

o   Electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system. Consist of keyboard, a video Display screen and a communication line to a mainframe computer.

B.1) Dumb Terminal

o   Used to input data to and receive information from a computer system. It cannot do any processing. Example is a Airline Ticket

B.2) Smart Terminal

o   Can do input and output and has some limited processing capability. Example is ATM.

B.3) Intelligent Terminal

o   Is a stand alone with its own input, output, processing and storage capacity and its own software. It is essentially a full-ledge micro computer with a communications link. Ex. Workstation.

I.2 Pointing Devices

A device with which you can control the movement of the pointer to select items on a display screen

a)      Mouse

o   A mouse is a small handheld device pushed over a horizontal surface. A mouse moves the graphical pointer by being slid across a smooth surface.

b)      Trackballs

o   Consist of a ball housed in a socket containing sensors to detect rotation of the ball about two axes, similar to an upside-down mouse: as the user rolls the ball with a thumb, fingers, or palm the mouse cursor on the screen will also move. 

c)       Touch Screens

o   Form of a light-sensitive wand used in conjunction with a computer's CRT TV set or monitor.

d)      Light pens

o   Similar to a touchpad, but controlled with a pen or stylus that is held and used like a normal pen or pencil. The thumb usually controls the clicking via a two-way button on the top of the pen, or by tapping on the tablet's surface.

e)      Digitizing tablets

o   Similar to a touchpad, but controlled with a pen or stylus that is held and used like a normal pen or pencil. The thumb usually controls the clicking via a two-way button on the top of the pen, or by tapping on the tablet's surface.

f)       Pen-based systems

o   Computer that uses pattern-recognition software to enable it to accept handwriting as a form of input.

I.3 Game Controllers

A game controller is a device used with games or entertainment systems used to control a playable character or object.

a)   Steering Wheel

o   Larger version of a paddle. Used in most racing arcade games

b)   Joystick

o   Control device you would find on an arcade game at your local arcades. Allows an individual to easily move an object in a game such as navigating a plane in a flight simulator.

c)    Gamepad or  Joypad

o   Game controller held in the hand, where the digits (especially thumbs) are used to provide input. Gamepads generally feature a set of action buttons handled with the right thumb and a direction controller handled with the left.

d)   Paddle

o   A paddle is a game controller with a round wheel and one or more fire buttons, where the wheel is typically used to control movement of the player object along one axis of the video screen. A paddle controller rotates through a fixed arc (usually about 330 degrees); it has a stop at each end.

I.4 Imaging and Video Input Devices

Video input devices are used to digitize images or video from the outside world into the computer. The information can be stored in a multitude of formats depending on the user's requirement.

a)   Image Scanners

o     A device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image.

b)   Webcam

o     A webcam is a video camera which feeds its images in real time to a computer or computer network, often via USB, ethernet or Wi-Fi.

c)    Fingerprint reader

o     Automated method of verifying a match between two human fingerprints. Fingerprints are one of many forms of biometrics used to identify individuals and verify their identity.

d)   3D Scanner

o     device that analyzes a real-world object or environment to collect data on its shape and possibly its appearance 

e)   Smart Cards and Optical Cards

o     A smart card is a plastic card about the size of a credit card, with an embedded microchip that can be loaded with data, used for telephone calling, electronic cash payments, and other applications, and then periodically refreshed for additional use.

f)    Voice Recognition Devices

o     Program capable of recognizing a user's speech. Voice recognition processing unit which recognizes the input voice.

I.5 Audio-Input Devices

In the fashion of video devices, audio devices are used to either capture or create sound. In some cases, an audio output device can be used as an input device, in order to capture produced sound.

a)   Microphone

o     Is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal.

Used in many applications such

o     tape recorders,

o     karaoke systems,

o     hearing aids, 

o     motion picture production,

o     megaphones,

o     in radio and television broadcasting

o     in computers for recording voice,

o     speech recognition

b)   Midi-Keyboard

o     A MIDI keyboard is typically a piano-style user interface keyboard device used for sending (MIDI) signals or commands over a USB or MIDI cable to other devices connected and operating on the same MIDI protocol interface

I.6 Sensors

A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument

I.7 Human Biology Input Devices

Human-biology input devices include biometric systems, which use biometrics the study of body characteristics, to identify people through biological characteristics, and line-of-site systems, in which people point their eyes at a screen.

o  Biometrics

ü   Science of measuring individual body characteristics. Biometric security devices identify a person through a fingerprint, voice intonation, or other biological characteristic.

II. Output Hardware

o   Devices that translate information processed by the computer into a form that humans can understand. Output hardware converts machine-readable information into people-readable form. Three types of output are softcopy, hardcopy, and other.

II.1 Permanent or Hard Copy

Hardcopy refers to printed output.

A. Printers

o  Output device that prints characters, symbols, and perhaps graphics on paper or another hardcopy medium. Two types of printers are impact printers and nonimpact printers.

Impact Printer

ü  Printer that forms characters or images by striking a mechanism such as a print hammer or wheel against an inked ribbon, leaving an image on paper. One type is the dot-matrix printers, which contains a print head of small pins

Non-impact Printer

ü  Nonimpact Printers form characters or images without direct physical contact between printing mechanism and paper. Three types of nonimpact printers are:

®     Laser Printer

A laser printers creates images with dots like a photocopying machine; the printer uses a page description language, software that describes the images to the printer. 

®     Ink-jet Printer

An ink-jet printers sprays electrically charged droplets of ink at high speed onto paper.

®     Thermal Printer

A thermal printer uses colored waxes and heat to burn dots onto special paper. 

B. Plotters

o  A special kind of printer, which may be ink-jet or electrostatic, produces high-quality graphics, such as maps, that are too large for regular printers.

C. Multi-function Printer

o  Another category of printer is the multifunction printer, which combines printing, scanning, copying, and faxing in one device.

II.2 Temporary or Soft Copy

o   Refers to nonprinted data, such as that shown on a display screen.

A.      CRT (cathode ray tube) - CRT (cathode-ray tube) is a vacuum tube. 

B.      Flat-panel display (LCD) - A flat-panel display consists of two plates of glass separated by a layer of a substance in which light is manipulated. One technology is liquid crystal display (LCD) in which molecules of liquid crystal create images by transmitting or blocking light. Flat-panel screens are either active-matrix display in which each pixel on screen is controlled by its own transistor and so the image is brighter and sharper, or passive-matrix display, in which a transistor controls a row or column of pixels. Two common color and resolution standards:

•       SVGA (the most common)-- which can produce 16 million possible colors, and 

•       XGA-- which can produce 65,536 possible colors.

•        

C.      Plasma Display Devices- A plasma display panel (PDP) is a type of flat panel display common to large TV displays 30 inches (76 cm) or larger. They are called "plasma" displays because the technology utilizes small cells containing electrically charged ionized gases, or what are in essence chambers more commonly known as fluorescent lamps.

D.      Multimedia Projectors- Processes a specific video signal and projects a corresponding image on a large screen using a lens system. This machine transfers images from a videotape, film reel, or DVD and enlarges the image to a movie screen or blank wall.

E.       Audio- Output (voice and sound –output) -These devices allow people to listen to music and other sound types, and manipulate audio elements such as volume, tone and pitch. Audio output devices come in the form of personal headsets, music players and computer speakers.

F.       Video output (Film Recorder) - Is a graphical output device for transferring digital images to photographic film. Used to produce the master copies of movies that use computer animation or other special effects based on digital image processing.

G.     Action - Consists of processing data that initiate some form of action or process control activity.

•       CAD/ CAM (Computer-aided design/ Computer-aided manufacturing/ machining)

Computer-aided Manufacturing

®     The use of computer software to control machine toolsand related machinery in the manufacturing of work pieces. Refer to the use of a computer to assist in all operations of a manufacturing plant, including planning, management, transportation and storage.

Computer-aided Design

®     Is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer.

•       Robotic System

®     Robots are comprised of several systems working together as a whole. The type of job the robot does dictates what system elements it needs. Robotic systems continue to evolve, slowly penetrating many areas of our lives, from manufacturing, medicine and remote exploration to entertainment, security and personal assistance.

The general categories of robot systems are:

1.       Controller - The controller is the robot's brain and controls the robot's movements. 

2.       Body- The body of a robot is related to the job it must perform. 

3.       Mobility- How do robots move? It all depends on the job they have to do and the environment they operate in.

4.       Power- Power for industrial robots can be electric, pneumatic or hydraulic

5.       Sensors- Sensors provide the raw information or signals that must be processed through the robot's computer brain to provide meaningful information

6.       Tools - As working machines, robots have defined job duties and carry all the tools they need to accomplish their tasks onboard their bodies. 

III. Processing Hardware

o  The main chip in the computer is the central processing unit CPU. It is called the CPU because its main function is to process instructions, manage the flow of information through the computer system, and perform calculations. It is the heart of the computer and communicates with the output, input and storage devices to perform tasks that are important to the functioning of the computer.

CPU Central Processing Unit

®  Control Unit - Tells the rest of the computer system how to carry out a program’s instruction

®  Arithmetic/ Logic Unit (ALU) - Performs arithmetic operations and logical operations and controls the speed of those operations.

Types of Computer Memory

o  RAM (Random-access memory)

ü  Volatile, temporary storage, the contents are lost when the computer is turned off.

ü  The two main forms of modern RAM are static RAM (SRAM) and dynamic RAM.

®     Static RAM (SRAM)

A form of volatile memory similar to DRAM with the exception that it never needs to be refreshed as long as power is applied. (It loses its content if power is removed).

®     Dynamic RAM (DRAM)

A form of volatile memory which also requires the stored information to be periodically re-read and re-written, or refreshed, otherwise it would vanish.

o  ROM (Read-only memory)

ü  Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware 

ü  Non-Volatile; a permanent software is installed during manufacturing; used to hold system programs and language.

How Data and Programs are Represented in the Computer

o  computer works with binary number system that is consist of only two digits zero and one.

o  Inside the computer binary number is represented by an electrical pulse.

o   All the data enters into the computers first converts into the binary number system.

Binary Rules!!!

o  Computers represent numbers in a system called binary numbers

ü Binary Numbers – numbers formed out of digits 0 and 1. Corresponds to computer electrical circuits being ON or OFF (1 = ON &0 = OFF). Computers describe a number as a power of two since each switch can be just one of two positions – ON or OFF.

Bit = Binary Digit = 0 or 1

Binary System – Bit, Byte, Word

o  1 byte holds one character of data. Computers ‘think’ in binary numbers and store all data (letters, numbers, symbols, images, etc.) in patterns of 0s and 1s.

o  Word Size

ü Number of bits that are manipulated as a unit by a CPU. Today, it is normally 32 or 64 bits.

What are Three Popular Coding Systems to Represent Data?

o  ASCII—American Standard Code for Information Interchange, most widely used for computers; originally a 7-bit character encoding system, now an 8-bit character encoding.

o  Unicode—coding scheme capable of representing all

world’s languages

o  EBCDIC—Extended Binary Coded Decimal Interchange Code, now an 8-bit character encoding commonly used in mainframes.

SAMPLE:

How is a Letter Converted to Binary Form and Back?

 

IV. Storage Hardware

Storage capacity of computers is expressed in bits, bytes, kilobytes, megabytes, gigabytes, terabytes, petabytes, or exabytes.

 Primary Storage – RAM

Secondary Storage – or auxiliary storage is any storage device designed to retain data and instruction (programs) in a relatively permanent form.

o  Tape storage (magnetic tapes, cartridge tape units)- Magnetic tape has been used for data storage for over 50 years. Modern magnetic tape is most commonly packaged in cartridges and cassettes. The device that performs actual writing or reading of data is a tape drive. 

o  Diskette Storage (floppy disks or diskette) - A floppy disk is a data storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a square or rectangular plastic carrier lined with fabric that removes dust particles.

o  Hard Disks – rigid metal platters that hold data as magnetized spots. A hard disk drive (HDD) is a non-volatile, random access digital data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure

o  Floptical Disks- a cartridge disk that relies on a combination of magnetic and optical technology. An outdated medium-capacity removable disk storage system, first introduced by Iomega in 1994.The name is a portmanteau of the words 'floppy' and 'optical'.

o  Optical Disks - An optical disc is a flat, usually circular disc which encodes binary data (bits) in the form of pits and lands on a special material on one of its flat surfaces.

Compact Disc

The Compact Disc (also known as a CD) is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively

—  CD-ROM- Compact disk read-only memory

—  CD-R – compact disc recordable

—  CD-RW- compact disc re-writable

—  DVD-R – digital versatile disc recordable

—  DVD-RW- digital versatile disc re-writable

—  WORM discs- write-once –read – many

—  Bl u-ray – mainly used in high definition video and data storage.

ü The disc has the same physical dimensions as standard DVDs and CDs. The name Blu-ray Disc is derived from the blue laser (violet-colored)) used to read and write this type of disc.Because of the beam’s shorter wavelength (405 nm), substantially mare data can be stored on a Blu-ray Disc than on DVD format, which uses a red (650 nm) laser. A two-layer Blu-ray Disc can store 50gigabytes, almost six times the capacity of a two-layer DVD, or ten times that of a single-layer DVD.

—  Lightsccribe – LightScribe is an optical disc recording technology that uses specially coated recordable CDand DVD media to produce laser-etched labels with text or graphics, as opposed to stick-on labels and printable discs.

V. Communication Hardware

Communication hardware ffacilitates the connections between computers and between groups of connected computer (networks)

Modem

-           (modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information.

Fax modem

-          Enables a computer to transmit and receive documents as faxes. A fax modem is like a data modem but is designed to transmit and receive documents to and from a fax machine or another fax modem.

Network Interface Card

-          Also known as a network interface controller, network adapter, LAN adapter). A computer hardware component that connects to a computer network using broadband connection.

Wireless Network Interface Card

-          Used for wireless connection to a LAN or the internet.

Peripheral

-          A piece of a computer hardware that is attached to a host computer to expand its capabilities. The term is used to describe those devices that are optional in nature. The term is also applied to devices that are hooked up externally, typically through some form of computer bus like USB. Typical examples include joysticks, printers and scanners.

Computer port

-          In computer hardware, a port serves as an interface between the computer and other computers or peripheral devices. Physically, a port is a specialized outlet on a piece of equipment to which a plug or cable connects. Electronically, the several conductors making up the outlet provide a signal transfer between devices. The term "port" is derived from a Latin word "porta" (gate, entrance, door).

Parallel

-          Parallel ports send multiple bits at the same time over several sets of wires.A type of interface found on computers for connecting various peripherals. Also known as Printer Port and Centronics Port.The IEEE 1284 standard defines the bi-directional version of the port.

Serial

-          Serial ports send and receive one  bit at a time via a single wire pair (Ground and +/-). Serial communication physical interface through which information transfers in or out one bit at a time (contrast parallel port).While such interfaces as Ethernet, FireWire, and USB all send data as a serial stream, the term "serial port" usually identifies hardware more or less compliant to the RS-232 standard, intended to interface with a modem or with a similar communication device.

PS/2

-          used for connecting some keyboards and mice to a PC compatible computer system. Its name comes from the IBM Personal System/2 series of personal computers, with which it was introduced in 1987. The PS/2 mouse connector generally replaced the older DE-9RS-232 "serial mouse" connector, while the PS/2 keyboard connector replaced the larger 5-pin/180° DIN connector used in the IBM PC/AT design. 

IEEE 1394

-          The IEEE 1394 interface is a serial bus interface standard for high-speed communications and isochronous real-time data transfer, frequently used by personal computers, as well as in digital audio, digital video, automotive, and aeronautics applications. The interface is also known by the brand names of FireWire (Apple), i.LINK (Sony), and Lynx (Texas Instruments).

USB Universal Serial Bus

-          A serial bus standard to interface devices to a host computer designed to allow many peripherals to be connected using a single standardized interface socket and to improve the plug-and-play capabilities by allowing devices to be connected and disconnected without rebooting the computer or turning off the device. Other conventional features include providing power to low-consumption devices without the need requiring manufacturer specific, individual device drivers to be installed

Ethernet

-          Port used to connect a computer to a wired network. A family of frame-based computer networking technologies for local area networks (LAN).