Hardware of Personal Computers

What are Basic Hardware of a Personal Computer?

• Monitor • Motherboard • CPU (Microprocessor) • Primary storage (RAM) • Expansion cards • Power supply • Optical disc drive • Secondary storage

(Hard disk) • Keyboard • Mouse

What is a Hardware?

• Hardware is the general term that is used to describe physical artifacts of a technology.

Classification of Hardware

What is an Input Device?

• A hardware mechanism that transforms information in the external world for consumption by a computer.

Input Devices

Keyboard for the input of text and characters and also to control the operation of a computer .

Mouse a pointing device by detecting two-dimensional motion relative to its supporting surface.

Scanner a device that analyzes images, printed text, or handwriting, or an object and converts it to a digital image .

Input Devices

Microphone an acoustic to electric transducer or sensor that converts sound into an electrical signal.

WebCam a real-time camera (usually, though not always, a video camera) whose images can be accessed using the World Wide Web.

Digital Camera an electronic device used to capture and store photographs electronically in a digital format

What is a Processing Unit?

• A central processing unit (CPU), is the component in a digital computer that interprets computer program instructions and processes data.

• There are 2 major CPU manufacturers for personal computers. Intel http://www.intel.com/ AMD http://www.amd.com

Figure 3. Intel Celern 2.66GHz CPU (Front)

Figure 4. Intel Celern 2.66GHz CPU (Back)

How fast is a CPU?

• When you choose a CPU, you should consider its speed.

• The speed of a CPU is determined by 2 main factors.

• Clock frequency

• Amount of cache memory

• The higher the value, the faster the CPU will be.

The clock frequency of a CPU

What is a motherboard?

• A motherboard is the central circuit board making up a personal computer.

CPU

RAM slot

Motherboard

• A personal computer is built with the CPU, main memory, and other essential components on the motherboard.

• Other components such as external storage, controllers for video display and sound, and peripheral devices are typically attached to the motherboard via edge connectors and cables.

• In modern computers it is increasingly common to integrate these "peripherals" into the motherboard.

What is a Video Card?

• A video card is to generate and output images to a display.

A Video Card

• If the video card is integrated in the motherboard, it will use the computer RAM memory (lower throughput). If it is not integrated, the video card will have its own video memory which is called Video RAM or VRAM.

• The VRAM capacity of most modern video cards range from 128 to 2048 MB (workstation graphics cards).

• In 2006, the VRAM was based on DDR technology, standing out DDR2, GDDR3 and GDDR4. The memory clock rate is between 400 MHz and 1.6 GHz.

• A very important element of the video memory is the Z-buffer, which manages the depth coordinates in 3D graphics.

What is a Sound Card?

A sound card is a computer expansion card that can input and output sound under control of computer programs.

• Many computers have sound capabilities built in on the motherboard, while others require these expansion cards if audio capability is desired.

What are Types of Storage Devices?

What is Primary Storage?

• Primary storage is computer memory that is directly accessible to the CPU of a computer without the use of computer's input/output channels.

• Primary storage is used to store data that is likely to be in active use.

What is ROM?

• Read-only memory (ROM) is a class of storage media used in computers.

• Data stored in ROM cannot be modified.

• ROM is a non-volatile storage. Data remains unchanged even after switching off the computer. E.g. EPROM, EEPROM

What is RAM? • Random access memory

(RAM) is a type of data storage used in computers.

• It takes the form of integrated circuits that allow the stored data to be accessed in any order (random).

• Data stored in RAM can be modified.

• RAM is a volatile storage. Data will lose after switching off the computer. E.g. DDRam, DDR-2 Ram

What is Secondary Storage?

• Secondary storage is computer memory that is not directly accessible to the CPU of a computer, requiring the use of computer's input/output channels.

• It is used to store data that is NOT in active use.

• It is usually slower than primary storage but it always has higher storage capacity.

• It is non-volatile. Data remains unchanged even after switching off the computer.

Secondary Storage

3.5” Floppy Disk

• Data can be read or write

• Data capacity: 1.44 MB

Secondary Storage

Hard Disk

• Data can be read or write

• Speed of disk rotation usually 7200 rpm

• Data capacity : 80GB, 160GB, 250GB, 300GB etc

Secondary Storage

CD-ROM CD-R CD-RW

Data can be Read only Read but write once

Read & write

Data Capacity (MB)

650 650 650

Secondary Storage

DVD DVD-R / DVD+R

DVD-RW / DVD+RW

Data can be Read only Read but write once

Read & write

Data Capacity Single layer: 4.7 Double layer:8.5

Single layer: 4.7 Double layer:8.5

Single layer: 4.7 Double layer:8.5

What are the difference between DVD-R and DVD+R? • The DVD-R format was developed by Pioneer in the

autumn of 1997. It is supported by most DVD players, and is approved by the DVD Forum.

• DVD+R was developed in 2002.

• This format is a competing format to the DVD-R format, which is developed by the DVD Forum, it has not been approved by the DVD Forum, which claims that the DVD+R format is not an official DVD format.

Secondary Storage

Secondary Storage

Secondary Storage

USB flash drives • They are flash memory

data storage devices integrated with a USB interface.

• They are typically small, lightweight, removable and rewritable.

• Data capacity: 512MB, 1GB, 2GB, 4GB, etc

Secondary Storage

Memory Cards

• e.g. SD card, CF card, xD card, Microdrive, Memory Stick

• Data can be read or write

• Data capacity: 512 MB, 1GB, 2GB, 4GB etc

Various Types of Memory Cards

SM Card

SD Card

CF Card

XF Card

Memory Stick

Microdrive

What is an output device?

• Output devices include any hardware that translate information processed by the computer into a form that humans can understand.

Output Devices A monitor is a piece of

electrical equipment which displays texts and images.

• It generated a temporary record because the record disappear when power off.

• There are 2 major types of monitors: Cathode Ray Tube (CRT) and Liquid Crystal Display (LCD)

The performance parameters of a monitor are:

1.Luminance

2.Size, measured diagonally For CRT the viewable size is one inch smaller then the tube itself.

3.Dot pitch Describes the distance between pixels of the same color. In general, the lower the dot pitch (e.g. 0.24), the sharper the picture will appear.

4. Response time The amount of time a pixel in an LCD monitor takes to go from active (black) to inactive (white) and back to active (black) again. It is measured in milliseconds (ms). Lower numbers mean faster transitions and therefore fewer visible image artifacts.

5. Refresh rate The number of times in a second that a display is illuminated.

6. Power consumption 7. Display resolution

The number of distinct pixels in each dimension that can be displayed.

Output Devices

A printer produces a hard copy (permanent human-readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper.

• There are 2 major types of printers. They are inject printer and laser printer.

• The resolution of a printer is measured in dots per inch (dpi). The higher the value, the better the quality.

Output Devices

Inkjet printers operates by propelling tiny droplets of liquid ink onto paper.

• They are the most common type of computer printer for the general consumer due to their low cost, high quality of output, capability of printing in vivid colour, and ease of use.

Output Devices

Laser printer

• Laser printers employ a xerographic printing process.

• Laser printers are available in both colour and black & white varieties.

Output Devices

• A loudspeaker is an electromechanical transducer which converts an electrical signal into sound.

References

• HP. (2007a). HP Officejet Pro K5400dn. Retrieved July 7, 2007, from http://h10010.www1.hp.com/wwpc/hk/zh/sm/WF06b/1090037-1090093-1095469-1095469-12224252-12973294-78107983.html

• HP. (2007b). HP Olaser Jet 1022. Retrieved July 7, 2007, from http://h10010.www1.hp.com/wwpc/hk/zh/ho/WF05a/1090037-1090121-1090401-1090401-1091129-12094322.html