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S2 Computer Literacy

S2 Computer Literacy. Computer Hardware. Overview of Computer Hardware. Motherboard CPU RAM Harddisk CD-ROM Floppy Disk Display Card Sound Card LAN Card. Motherboard. It is the main circuit board that links all the hardware components together .

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S2 Computer Literacy

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  1. S2 Computer Literacy Computer Hardware

  2. Overview of Computer Hardware • Motherboard • CPU • RAM • Harddisk • CD-ROM • Floppy Disk • Display Card • Sound Card • LAN Card

  3. Motherboard • It is the main circuit board that links all the hardware components together. • There are many chips or IC (Integrated Circuit) on the motherboard which contains millions of transistors.

  4. CPU (Central Processing Unit) • It interprets and performs instructions of a computer program. • The most determining factor in how powerful a computer is. • A CPU in a common PC system is known as the microprocessor.

  5. A model of Computer

  6. CPU • A CPU consists of two parts, the ALU and the CU. • Both the ALU and the CU contains registers, which are • high-speed memory • temporarily hold data and instructions during processing.

  7. Different kind of CPU • Common features • Clock rate > 2GHz • Intel • Celeron • Pentium 4 • Xeon • AMD • Duron • Athlon XP • Sempron • Athlon 64 • Differences • Word Size • Cache Memory Size • Front Side Bus • No. of transistors

  8. RAM • RAM –Random Access Memory • RAM is volatile • data is lost when the power to the computer is turned off • The instructions and data for the job performing are written to RAM and read from it as needed.

  9. Secondary Storage • CPU can only process data in RAM • But RAM is volatile, processed data cannot be stored in RAM • Secondary Storage device is needed • It is a non-volatile storage media which has a big storage size.

  10. Secondary Storage

  11. Magnetic Media - Floppy • Floppy • 1.44 MB • Plastic disk with magnetic coating • Reading and writing speed is slow • Data easily lost • Some new kind of floppy called SuperDisk and ZipDisk have larger capacity, but need special drives to read the disk

  12. Magnetic Media – Hard disk • Hard disk • Huge storage capacity • A set of circular metal plates with magnetic coating • Read/write head inside • Rotate at a very high speed for faster data access

  13. Magnetic Media – Hard disk • Inside the Hard disk

  14. Optical Media - CD • CD –Compact Disk, using laser technology • Normally it can store 640MB data. • It is cheap and durable. • Data is stored by "burning" pits and lands on the metal coating. • A laser beam is projected to the disc surface and the reflection will be read to detect the patterns of pits and lands.

  15. Optical Media - CD • The way CD read data • The way CD drive rotate the disc

  16. Optical Media – CD-R/CD-RW • CD-R (CDRecordable) and CD-RW (CDRewriteable) • Both of them allow users to write data onto a CD-R or CD-RW disc. • CD-R • can be written only once • CD-RW • can be write and overwritten for many times.

  17. Optical Media – DVD-ROM • It is similar to CD-ROM but its capacity varied from 4.7GB to 17GB. • A DVD-ROM drive is needed to read data from a DVD-ROM. • As its capacity is large, film companies use them to publish high quality film.

  18. Optical Media – DVD R/DVD RW • It is similar to CD-R and CD-RW, but has a much higher capacity. • There are different standard • DVD+R, DVD-R • DVD+RW, DVD-RW • DVD-RAM • Different disc drives and different discs are not compatible • Most DVD writers support RW standard • DVD-R, DVD-RW seems to be the most popular standard

  19. Semi-conducting Media • It is sometimes called flash memory, where it uses semi-conductor chips to store data. • No mechanical movement involved in data transfer, so it is: • Quiet in operation • Not easy to be damaged • Used in portable devices such as: • PDA (Personal Digital Assistant) • MP3 player • Digital camera

  20. Semi-conduction Media • Flash Thumb Drive • CF card • SD card • Card Reader • Memory Stick

  21. Measuring SecondaryStorage device • Access time • The average time it takes the device to locate data on the storage medium and read it. • Lower access time indicates higher speed. The unit is usually in ms.

  22. Measuring SecondaryStorage device • Data Transfer Rate • The amount of data that a storage device can move from the storage medium to the computer per second. • Higher data transfer rate indicates higher speed. The unit is usually measured in MB/s.

  23. Measuring SecondaryStorage device • Storage Capacity • It is the maximum amount of data that can be stored on a storage medium. • The unit is usually measured in KB, MB, and GB.

  24. Measuring SecondaryStorage device

  25. Input Device • An input device is any hardware that allows a user to enter data and commands into a computer.

  26. Input Device – Touch Screen • A pressure sensitive display that allows users to select options with fingers or stylus. • Not designed for inputting large amount of text. • It is often used in information kiosk, PDA and tablet PC.

  27. Scanner • Just like a photocopier, it sends bright light on the document and detects the light reflected from the source document. • The data detected are converted into a digital graphics.

  28. Barcode Reader • Books in library and goods in supermarket are given a unique bar code. • A bar code reader will be used for check out. • It is highly accurate and fast.

  29. Voice Input • A user can use a microphone to input sound into a computer. • A technology called voice recognition can be applied to analyze the speech into text.

  30. Output Device • An output device is a hardware that presents digital information in a form that human being can understand.

  31. Output Device – CRT Monitor • It is heavy and occupies a lot of desk space.

  32. Output Device – LCD Monitor • LCD monitors are thinner in size but more expensive than CRT monitor. • Notebook computer, tablet PC have an integrated LCD monitor.

  33. Output Device – Inkjet Printer • It spraystiny ink drops onto paper from an ink-filled print cartridge. It can produce low-cost colour printout.

  34. Output – Laser Printer • a laser beam to produce an electronically-charged image on a drum, causing toner to stick to the drum whether the laser hits. • toner is transferred to the paper as the drum presses against it and a heating process follows which fixes the toner onto the paper. • This technology is similar to that used in a photocopying machine.

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