Input / Output / Storage / Communication Devices

Input / Output / Storage / Communication Devices By Muhammad Mustaqim 12B1

Input devices

Keyboard • Used to input data into the computer • Advantage • They are very common; all computers have one and they are easy to use. • Disadvantage • Easy to make mistakes if you can’t type quickly. • Mouse Enables you to control the movement of the on screen curser by moving it around a surface • Advantage • Easy to learn to use • Accurate for selecting things • Disadvantage • Need a flat space next to the computer.

Joystick • Similar to a tracker ball in operation except you have a stick which is moved rather than a rolling ball. • Advantage • Immediate feel of direction. • Disadvantage • Some people find them more difficult to use than mice. • Microphone • Used to input sound • Advantages • Some systems can understand most peoples voices with voice recognition software • Disadvantages • Some systems need to be trained to understand each different voice.

Digital Camera • Looks very similar to a traditional camera. However, unlike photographic cameras, digital cameras do not use film • Advantage • No film needed. • Images can be digitally manipulated • Disadvantage • Need to print out photographs • Scanner • Another way in which we can capture still images or text to be stored and used on a computer. • Advantage • Can input things from paper documents • With OCR software, text can be scanned in • Disadvantage • Images can take up a lot of memory space.

Output devices • Once the computer has processed all the information from the inputs then it must display or output the information in some way. • This is when we use Output devices that enable us to see or hear the information stored in the computer.

Monitors • Cathode Ray Tube: monitors are fairly large and they are not as common as LCD’s nowadays. CRT’s work by using an electron gun situated at the end of the tube. • Advantage • They give a better quality display. • Robust and hard to damage • Disadvantage • They produce a lot of heat. • Liquid Crystal Display : monitors are thin and are more commonly used. They work by using electronically charged crystals. • Advantage • Produce less heat • Take less space • Disadvantage • Easily damage

Speakers Most computers are fitted with a small internal speaker which can produce beeping sounds to alert you if you make an error. Advantages • They can help blind people to use the computer because text can be converted into sound Disadvantages • High quality external speakers can be expensive Headphones/Earphones Headphones or earphones consist of a small pair of loudspeakers which are worn over or in the ears. Advantages • Portability • The sound can be heard by the user and won’t disturb others Disadvantages • Often not aware of surroundings • Risk of permanent hearing loss

Storage devices • A data storage device is a device for recording (storing) information(data). • There is internal and external storage devices Internal R.A.M • Random access memory is a form of computer data storage. • Temporary, short-term working memory • It’s also known as ‘volatile memory’ because the data disappears if the power is switched off. R.O.M • Read only memory • It is permanent, long term memory which cannot be erased or changed in any way • It’s also known as ‘non-volatile memory because it doesn’t disappear after the computer is switched off.

External Hard Disk An external storage device which can contain a lot of data. Advantages • Main Backing storage for files and programs • Can store lots of data compared to the floppy disc Disadvantages • Slow to access • Data can be damaged easily or reformatted CD-ROM Advantages • Data cannot Be erased – you cannot lose your data • Easy to carry around • Cheap to produce Disadvantages • Fragile • Can scratch easily – this effects the data when the laser reads it • Slower to access than a hard drive

Communication devices These are devices that can communicate with other people who are out of range or long distances. Mobile phones The work using the transmission of electromagnetic radio waves. They have a transceiver that is only powerful enough to transmit or receive date from the nearest mobile Advantages • They can be used while travelling if a public phone is unavailable. • They can be used to send photos and videos. Disadvantages • They cost more than a landline • They have a limited battery life

Global Positioning System GPS work by making use of satellites that orbits the earth. They can be used by runners or drives to pinpoint their speed and position Advantage • Greater accuracy for measuring distances Disadvantages • They are expensive • Transmission can be slow Handheld & PDA’s They refer to any type of small computers that can be carried in one hand. They are used by pros whose job requires them to be travelling some or much of the time Advantage • They are easier to carry than a laptop Disadvantages • They are expensive as laptops • Its difficult to enter much text

Storage and memory • Across • 3. This can only store 0 and 1 • 4. Magnetic tape can also be known as magnetic ......... • 7. WORM stands for 'write once read ....‘ • 8. This contains 1024 kilobytes • 9. RAM stands for Random ...... Memory Down • 1. A byte is made up of how many bits? • 2. Memory that loses its data when the power is switched off is known as ........ • 3. When you make a copy of your work onto a storage device, it is known as making a ...... • 5. When your computer first starts up, it is using its ... • 6. A hard disk is measured in .........

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Input / Output / Storage / Communication Devices