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UNIT 1. Storage Device. It is the amount of data that can be stored in the storage unit. A large capacity is desired. As compared to secondary storage units, primary storage units have less storage capacity.
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Storage Device • It is the amount of data that can be stored in the storage unit. A large capacity is desired. As compared to secondary storage units, primary storage units have less storage capacity. • Any storage unit of a computer system is characterized and evaluated based on following properties – storage capacity, access time, cost per bit of storage, volatile and random access.
Types of storage device • Optical storage device- CD • Optical storage device- DVD • Optical storage device- Blu-Ray • Magnetic storage device- Floppy disk • Magnetic storage device- Hard disk • Solid state device- Flash memory & Memory stick
Optical storage device- CD • CD-ROM : CD Read only memory. When you buy a CD from a store, you can read it, but you can’t save any thing on it. • CD-RW : CD Read Write. You can save your data over and over again, like a floppy disk. • Advantages : • Small and portable • Very cheap to produce • Most computers can read CDs. If there is no CD drive, a DVD drive can usually read them • Disadvantages : • Fairly fragile, easy to snap or scratch • Smaller storage capacity than a hard drive or DVD • Slower to access than the hard disk.
Optical storage device- DVD • DVD-ROM : A new type of read only compact disc that can hold a minimum of 4.7GB. • DVD-RW : The data on a DVD-RW disc can be erased and recorded over numerous times without damaging the medium. • Advantages : • Very large storage capacity • DVD players can read CDs • DVDs are now mass produced so they are relatively cheap • Disadvantages : • DVDs do not work in CD drives • There is no single standard of DVD • They can be easily damaged by breaking or scratching
Magnetic storage device- Floppy disk • Floppy disk : It can only store up 1.44Mb of data. All disks must be formatted before data can be written to the disk. Formatting divides the disk up into sections or sectors onto which data files are stored. • Advantage : • Small & light – easy to carry • Cheap • Useful for transferring small files • Disadvantage : • Easy to be damage • Small storage capacity • Many new computer don’t have floppy disk drives
Magnetic storage device- Hard disk • Hard disk : the main storage device in computer. It is a bit like a filing cabinet: all of your data files and applications software are stored on it. It contains a number of metal platters which have been coated with a special magnetic material. The data is stored in this magnetic material.
Solid state device- Flash memory & Memory stick • Flash Memory : Memory sticks are available from 1 Gb up to 8 Gb. They are typically small, lightweight, removable and rewritable. They consist of a small printed circuit board which is encased in plastic or metal casing. They usually have a removable cap which covers and protects the part of the stick which is inserted into a USB port. • Advantage : • Hold more data than CD • More reliable than floppy disk, because they have no moving part • More compact and portable than floppy disks or CDs/DVDs. • Disadvantage : • Lost easily • The metal part which is inserted into the USB port can be snapped off if they are handled roughly • More expensive than floppy disks, CDs and DVDs
What are Output Devices ? Output Device is any hardware component that can convey useful information to one or more people.
DISPLAY DEVICES Output Devices that visually convey useful information in text, graphics and video. • Information on display device sometimes called soft copy. Monitor houses display device that is packaged as a separate peripheral
LCD MONITORS Liquid Crystal Display is a flat panel display. It uses the light modulating properties of liquid crystals. It can be found on Notebook, PC monitor, Mobile devices etc.
CRT MONITORS Contains Cathode Ray – Tube (CRT). Screen coated with tiny dots of phosphor material. • Each dot consists of a red, blue, and green phosphor. Common sizes are 15, 17,19,21 and 22 inches • Viewable size is diagonal measurement of actual viewing area.
PRINTERS Output devices that produces text and graphics on a physical medium. Result is hard copy, or printout. Two Orientations : Portrait and Landscape
INK – JET PRINTERS Forms characters and graphics without striking paper. Sprays tiny drops of liquid ink onto paper. It prints with black & white and coloured ink.
PHOTO PRINTERS Colour printer that produces photo – lab quality pictures. Many photo printers have a built in card slot. Pitch Bridge is a standard technology that allows you to print pictures directly from a digital camera.
LASER PRINTER High Speed, High Quality nonimpact printer. Print text and graphics in High Quality resolution, ranging from 1200 to 2400 dpi. Typically cost more that ink-jet printer, but is much faster.
THERMAL PRINTERS Generates images by pushing electrically heated pins against heat-sensitive paper. • Dye – sublimation printer (also called as digital photo printer) uses heat to transfer dye to specially coated paper
LABEL AND POSTAGE PRINTERS Small printer that prints on adhesive–type material. Aslo prints bar codes. Postage printer has built in digital scale and prints postage stamps.
PLOTTER Sophisticated printer used to produce high- quality drawings. Large – format printer creates photo realistic quality colour prints.
AUDIO DEVICES SPEAKERS, HEADSETS AND EARPHONES Computer components that make it possible for user to hear music, speech or other sounds. Speakers and headsets are commonly used audio devices.
OTHER OUTPUT DEVICES FAX MACHINE Device that transmits and receives documents over telephone lines. Converts an original document into a digitized image. Many printers include fax capabilities.
OTHER OUTPUT DEVICES DATA PROJECTOR Device that takes text and images from computer screen and projects them onto a larger screen. DLP Projector. LCD Projector.
OTHER OUTPUT DEVICES FLASH DRIVE It is a both input and output devices. It can be used to carry data and information that can latter be displayed on a screen. It is also known as USB drive. It comes in various storage capacities.
OTHER OUTPUT DEVICES INTERACTIVE WHITEBOARD TOUCH-SENSITIVE DEVICE THAT DISPLAYS THE IMAGE ON A CONNECTED COMPUTER SCREEN ALSO KNOWN AS SMART BOARD
Characteristics of Computers • Speed – MIPS/BIPS • Accuracy • Reliability – No human Intervention • Storage Capacity • Diligence – same result forever
Applications • At Home • Mostly to check mails • Small documentation • Gaming • Music and Video • To solve homework • Photo Printouts using Good Printers • Work from Home concept
Applications.. • In Education • Schools to Universities • To Educate necessary skills demanded by Industries • To give a demo or training • Server the purpose of Teaching Aids • To convey messages using Internet
Applications… • In Science • To analyze large data acquired over a period of time • To do complex floating point arithmetic • Image Processing • Research
Applications…. • In Industry • To develop software, mostly to automate the manual work • To provide necessary solution to clients’ needs • Software is developed for the needs of networking, banking, business, retail etc
Applications….. • Entertainment • Music Industry • Games • Movies – to watch and create – 200 Linux Machines in parallel to create visualization in Titanic, the movie • IIIly Cartoons, special effects • Nowadays to promote theirs productions
Business • Banking • To store, access and modify huge amounts of data • Online business called e-business is becoming popular with a small amount of limitations • Paying bills become easy and time saving • online promotions
Applications…… • Government • “Biometrics Attendance Monitoring” • Weather Forecasting and military applications • E- governance • Online payment of taxes, Insurances • Send Messages to virtually unreachable places at present • Wireless communication
A typical computer CPU Input Output Monitor Printer Projector Keyboard Mouse Joystick Stylus Memory Primary, Secondary & fixed, portable
Hardware and Software • Hardware • Whatever we see physically • Software • Set of instructions written using a language • Application Vs System software • Natural Vs Artificial Languages
Criticality of an Application • Science – Solve a problem using computer • Commercial – Payroll management • OLTP – Ticketing Reservation Systems • Process Control Applications – Boiler Pressure Control System • Satellite Communication
Software Classification • 1. Application Software • 2. System Software
Computer Classification • 1. Personal computer • 2. Workstation • 3. Videogame console • 4. Server • 5. Client • 6. Mainframe computer • 7. Supercomputer • 8. Handheld computer • 9. PDA • 10. Smart phone • 11. Portable media player • 13. Microcontroller
