Unit 1 - LO1 Understand Computer Hardware Flashcards
1.1 Computer Hardware
Input devices
Input devices enable a user to communicate with the computer.
Keyboard
+ Enables fast input of text
+ Easy to use
- Users with hand problems will find it hard to operate
- Entering data is low in comparison to an OMR
- Takes up desk space.
Mouse
\+ Faster to use a mouse than a keyboard \+ Enables rapid navigation \+ Small - Hard to use without a flat surface - Users with hand problems will find it hard to operate. - Easily damaged
Scanner
+ Images can be stored
+ Much faster and accurate than typing
+ Possible to recover damaged documents
- Quality can be limited depending on scanner quality
Sensors
\+ Accurate \+ Constantly on \+ Responds immediately \+ Doesn't need humans to operate - Faulty sensors can give incorrect results
Microphones
+ Faster to read text than to type it
+ Possible to manipulate sound using software
- Sound files can take up a lot of memory
- Voice recognition software isn’t as accurate as typing
Graphics Tablet
+ It is possible to modify drawings before they are input
+ Accurate method of drawing
- More expensive than other pointing devices
VDU/ Screen
\+ Faster entry of options \+ User friendly \+ Cannot be tampered with/ corruption - Limited number of options available - Can lead to health problems - Screens can get very dirty
Barcode reader
+ Faster than typing in information
+ Only the central database needs to be updated
- Expensive
- Barcodes can be swapped on items
- Computer technology and staff training needed
Output devices
Output devices allow the computer to communicate with the user
VDU/ Screen
+ Relatively cheap
+ Reliable
+ Most computing devices come with one
- Unsuitable for users with eye problems
Printters
+ Fast to use
+ Printer can be shared across network
- Maintenance and ink costs can become pricey
Plotters
+ They are accurate
+ Produce far larger printouts
- Slow
- Relatively expensive
Speakers
+ Usually long lasting and durable
+ Often provided with device
- Can take up desk space
- Not personal, everyone can hear it
Braille terminal
+ Effective output alternative for the visually impaired
- Cannot be used by any other users
Infrared
IR emitters send out IR light which travels through the glass scree
Infrared
. IR emitters send out IR light which travels through the glass screen
. IR sensors receive this light
. When the screen is touched the IR light scatters
. IR sensors will detect the less intense light and calculate the location of the touch
Resistive
. Uses a glass panel covered by a thin flexible film
. Both are covered in charged electrodes
. When the film is touched the two metallic coatings make contact, resulting in a change of electrical current
. This identifies the change point
Capacitative
. Uses a glass panel with a clear electrode layer on top
. When a finger touches the screen, some of the electrodes transfers to the finger
. This reduction is detected
Communication devices
Communication devices allow one computer device to connect to another.
Hub
Sends packets to all devices on the network.
+ Cheap so can be used as a temporary backup
- Slow as it cannot send and receive packets at the same time
Switch
Collects the MAC address of all devices on a network and send packets directly to them.
+ Faster and more efficient than a hub
- Expensive
Router
Forwards packets over a network
+ Monitors condition of the network to adapt to changes
- Has to be connected to more than 2 networks
Modem
Converts digital signals into analogue signals.
+ Can receive calls in absence of the user
- Can leave you vulnerable to malware and hackers gaining access to your devices
Wireless access point
Allows multiple devices to send and retrieve wireless communication.
+ Allows for a broader range of communication
- Allows for interception
Hybrid device
Combines the functionality of many communication devices.
+ Allows for the flexibility of a wireless network while providing speed for accessing large files
- Expensive
