Hardware software
- 1. PAAVAI COLLEGE OF EDUCATION Paavai Nagar, Nh-7,pachal, Namakkal - 637018 POWER POINT PRESENTATION 2011-2012
- 2. PAAVAI COLLEGE OF EDUCATION Paavai Nagar, Nh-7,pachal, Namakkal - 637018 POWER POINT PRESENTATION NAME : S.MANIKANDAN OPTIONAL : COMPUTER SCIENCE AND MATHS ROLL NO : 038
- 3. HARDWARE
- 4. Unofficial ICT Hardware Categories • Input • Output • Processing • Storage • Communication
- 5. Input Devices • Let users enter data into an information system. • Keyboard, keypad • Mouse, touchpad • Bar code reader • Touch screen • Data tablet • Scanner, camera • Voice recognition
- 6. Input Devices • Keyboard, keypad – QWERTY layout. Designed to be as inefficient as possible to stop fast typists jamming the early typewriters – Dvorak – more efficient key layout puts most commonly used keys on the home row. Rare!
- 7. Input Devices • Mouse, trackball – Designed for GUI OS – Ball mouse superseded by optical – RSI concerns – Trackball = stationary upside-down mouse • Touchpad – When mice are impractical – On laptops
- 8. Input Devices • Bar code reader – Reads bar codes – converts them to numbers – Common in supermarkets, libraries, parts warehouses etc – Much faster and more accurate than hand-typing product codes
- 9. Input Devices • Touch screen – Touch sensitive – Tablet computers – iPhone – Railway ticket machines – Information kiosks – Bank ATMs – Easy for public to use – Can mimic any sort of interface: buttons are only images
- 10. Input Devices • Data tablet – Far better than a mouse for art – Works like a pen – Pressure-sensitive
- 11. Input Devices • Scanner, digital camera – Digitises analogue documents or pictures – Scans page like a photocopier – Use OCR (Optical Character Recognition) to interpret and digitise printed text – Resolution determines how detailed the resulting digital image is. • 1200 dpi resolution = 1200 dots per inch (2.54cm)
- 12. Output devices 1 Display the results of processing. • Monitor – CRT – LCD, TFT – Plasma – Data projector
- 13. CRT monitor • Now extinct!
- 14. LCD monitors • LCD = Liquid Crystal Display • Thin, saves desk space • Lighter than CRT • Less power consumption than CRT • Getting cheaper • Refresh rates getting better • Blacks often just grey • Colour richness not as good as CRT
- 15. Data Projector • Very portable • Very large display • Struggles in brightly lit rooms • Colours are often dull • Excellent for group presentations • Lamps fail with age
- 16. Output devices 2 • Printer – Laser – Inkjet – Thermal – Dot matrix, Impact • Speakers • Indicators, LEDs
- 17. Inkjet Printers • Cheap to buy, very expensive to replace ink • Line-by-line printing
- 18. Dot matrix printers • The only printer type that strikes the paper… • Only they can produce duplicates with pressure-sensitive paper • E.g. supermarket receipts - two or three copies (white customer copy, yellow shop copy) in only one print operation
- 19. Storage hardware Stores & retrieves data and software. • Hard disk • Solid state disk • Flash RAM, RAM, ROM • CD, DVD • Tape, floppy disk
- 20. Hard Disk Drive • ‘HDD’ • Magnetic storage • Multiple aluminium platters stacked on a spindle • Average HDD platters 3½” (inches) • Laptop platters 2½” • MP3 players 1”
- 21. USB Flash Drives • NAND memory • Normal RAM (Random Access Memory) loses its memory contents when power is turned off • Normal ROM (Read Only Memory) has its contents burnt at the factory and they cannot be changed later
- 22. USB Flash drives • Small, light, rugged (sealed, no moving parts) • Cheap ones can be rather slow • Typical capacity from 64M to 64G. • Easily lost or left behind - possible security issues • Some USB Flash drives can be encrypted
- 23. CD, DVD • Aluminium layer embedded in a 5¼” polycarbonate plastic disc • Laser burns data digitally as pits • Data also read by laser beam • Continuous, spiral data track extends from innermost to the outermost track, covering the entire disc surface
- 24. CD, DVD • Sensitive to scratches, heat • Immune to magnetic effects • Not “perpetual storage” as originally believed. – Disks degrade over time, become unreadable – Gold disks seem to last longer The laser lens in a CD drive
- 25. THANK YOU BY S.MANIKANDAN