Basic computer hardware and software.

Basic Computer HardwareInstructorsSyed Asim Raza RizviPhysical devices that make up the computer are called hardware. Computers hardware devices fall into the following categories: Input and Output, Devices Expansion Cards Storage Devices & Processing Devices Hardware DefinitionInput DevicesAn input device is any hardware component that allows you to enter data and instructions into a computer

Keyboard The keyboard is used to type information into the computer or input information. The keys on computer keyboards are often classified as follows: Alphanumeric keys -- letters and numbers Punctuation keys -- comma, period, semicolon, and so on. Special keys -- function keys, control keys, arrow keys, Caps Lock key, and so on.

Input Devices (contd)MouseMost modern computers today are run using a mouse controlled pointerScannerA scanner converts text/image into a digital file, allowing the computer to read and/or display the scanned object. Touch ScreenIts a touch sensitive display device. Some models of desktop computers and notebook computers, including netbooks and Tablet PCs, and many mobile devices have touch Screen

Input Devices (contd)TouchpadIts a small, flat, rectangular pointing device that is sensitive to pressure and motion. Some touchpads have one or more buttons around the edge of the pad that work like mouse buttons.

TrackballA trackball is a stationary pointing device with a ball on its top or side. To move the pointer using a trackball, you rotate the ball with your thumb, fingers, or the palm of your hand. For users who have limited desk space.

Input Devices (contd)Optical Character Recognition usually abbreviated toOCR, is theelectronicconversion of scanned or photographedimagesof typewritten or printed text into computer-readable text. It is widely used as a form of data entry from some sort of original paper data source, such as passports, documents, business card, or any number of printed records

Optical Mark Recognition reads hand-drawn marks such as circles or rectangles. Used in paper based IELTS/TOEFL exams.

Input Devices (contd)Bar Code Reader is an optical reader that uses laser beams to read a bar code, or identification code. When you go shopping

Magnetic Stripe Card Reader reads text printed with magnetized ink. You can see it under the checks given by your bank.

Automated Teller Machine is a self-service banking machine that connects to a host computer through a network.

A Biometric device translates a personal characteristic into digital code that is compared with a digital code stored in the computer to identify an individual. A fingerprint reader captures curves and indentations of a fingerprint. A face recognition system captures a live face image

Output DevicesOutput devices are hardware components that convey information to one or more people

Output Devices (contd)MonitorA monitor is a video display screen and the hard shell that holds it. PrinterA printer is an output device that produces text and graphics on a physical medium such as paper. Types of printers are as followsInk-jet printerPhoto printerLaser printerMultifunction peripheral (all-in-one device)ProjectorA data projector is a device that takes the text and images displaying on a computer screen and projects them onto a larger screen so that an audience of people can see the image clearly. Speakers, Headphones, & Earbuds These are three commonly used audio output devices. An audio output device is a component of a computer that produces music, speech, or other sounds.

Output Devices (contd)

Expansion CardsSound CardA sound card is an expansion card or integrated circuit that provides a computer with the ability to produce sound like music and voice that can be heard by the user.

Video CardVideo cards plug into the motherboard and are used to display video.VRAM is video memory that enhances the refreshment rate of the image. Video cards have chipsets that can increase the speed of video display.

Network Interface CardAllow computers to connect together to communicate with each other. Network cards have connections for cable, thin wire or wireless networks.

Secondary StorageStorage: A location where information can be held permanently or temporarily for later use. The hard-drive is a mechanical storage device typically located internally. CharacteristicsFast recording and recovery of dataLarge storage capacityMagneticSpeed is measured in R.P.M.s (Revolutions per minute)

Data Storage Devices: Secondary StorageData Storage Devices: Secondary StorageCD-ROM (compact disk read only memory)Compact disks or CDs can store large amounts of information. One disk will store 650 Mb or about 70 or 80 minutes of music. One type is a CD-ROM which stands for Compact Disk Read Only Memory. Another type is a CD-RW which stands for Compact Disk - Read/Write.Digital Versatile DiscDVD disks can store over 4 gigabytes. DVD recorders allow you to store large files, such as movies, on a single disk. DVD+RW (TE)

Data Storage Devices: Secondary StorageFloppy diskette is magnetic storage device for small amounts of data (1.44MB). A USB flash drive, sometimes called a thumb drive, is a flash memory storage device that plugs into a USB port on a computer or mobile deviceAn ExpressCard module is a removable device mobile device that fits in an ExpressCard slot

Data Storage Devices: Primary StoragePrimary StorageRAM (random access memory) stores data that is processing. This type of memory is erased when the computer is turned off. ROM (read only memory) contains special instructions for the computer to operate.Cache memory increases the speed of the processor by recording and anticipating instructions.

Data Storage Devices: Primary StorageComputer memory is binary (0 or 1) (on or off).The byte is the standard unit of measurement.A byte is composed of 8 bits (binary digits).Typical units of measurement:1 KB (kilobyte) = 1000 bytes 1 MB (megabyte) =1000 kilobytes or 1 million bytes1 GB (gigabyte) =1000 megabytes or 1 billion bytes 1 Tb(Terabyte)= 1000 gigabytes or 1 trillon

Processing Unit (contd)CPU (Central Processing Unit) also called the Microprocessor or The Brain of the Computer.Processor speed: The speed at which a microprocessor executes instructions. This is usually measured in megahertz (MHz)/ Gigahertz(GHz).Currently the processors (i3,i5, and i7), made by Intel, are the most common CPU though there are many other companies that produce processors for personal computers. Examples are the CPU made by Motorola, Cyrix and AMDComputer chip: also called the microprocessor may contain an entire processing unit.

Processing Unit (contd) Computer chips contain millions of transistors. They are small pieces of semi-conducting material (silicon). An integrated circuit is embedded in the silicon. Computers are made of many chips on a circuit board.

Ports and PeripheralsPorts are an interface between the computer and another peripheral device such as a disk drive, mouse, printer, modem, monitor, camera, FLASH drive or keyboard.Examples: Serial Parallelhot-wire USB

Ports and Peripherals (contd)Peripherals are devices that plug into a computer and are not housed internally.Examples: PrintersScannersCameras

Comparison Between Secondary StorageType of Secondary StorageCapacityTransfer SpeedPortableCategoriesHard Disk DriveVery High (100 GB)Very FastNo-CD (Compact Disk)High (650 MB)FastYesCD-ROMCD-RW

DVD (Digital Versatile Disk)Very High (4 GB)FastYesDVD + RWFloppy DiskLow (1.44 MB)SlowYes-USB FlashVery HighFast Yes-