1. UNIT 1

2. 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.

3. 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

4. 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.

5. 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

6. 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

7. 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.

8. 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

9. What are Output Devices ?
Output Device is any hardware component
that can convey useful information to one or more people.

10. 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

11. 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.

12. 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.

13. PRINTERS
Output devices that produces text and graphics on a physical medium.
Result is hard copy, or printout.
Two Orientations : Portrait and Landscape

14. 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.

15. 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.

16. LASER PRINTER High Speed, High Quality nonimpact printer.
Print text and graphics in High Quality resolution, ranging from 1200 to dpi.
Typically cost more that ink-jet printer, but is much faster.

17. 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

18. 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.

19. PLOTTER Sophisticated printer used to produce high- quality drawings.
Large – format printer creates photo realistic quality colour prints.

20. 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.

21. 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.

22. 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.

23. 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.

24. OTHER OUTPUT DEVICES INTERACTIVE WHITEBOARD
TOUCH-SENSITIVE DEVICE THAT DISPLAYS THE IMAGE ON A CONNECTED COMPUTER SCREEN
ALSO KNOWN AS SMART BOARD

25. Input

26. Characteristics of Computers
Speed – MIPS/BIPS
Accuracy
Reliability – No human Intervention
Storage Capacity
Diligence – same result forever

27. 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

28. 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

29. Applications… In Science
To analyze large data acquired over a period of time
To do complex floating point arithmetic
Image Processing
Research

30. 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

31. 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

32. 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

33. 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

34. A typical computer CPU Input Output Memory Monitor Keyboard Printer
Mouse
Joystick
Stylus
Monitor
Printer
Projector
Memory
Primary, Secondary & fixed, portable

36. Hardware and Software Hardware Software Whatever we see physically
Set of instructions written using a language
Application Vs System software
Natural Vs Artificial Languages

37. 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

38. Software Classification
1. Application Software
2. System Software

39. Application Software

40. System Software

41. 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

42. Personal computer

43. Workstation

44. Videogame console

45. Server

46. Client

47. Mainframe computer

48. Supercomputer

49. Handheld computer

50. PDA

51. Smart phone

52. Portable media player

53. Microcontroller