Computer Hardware - Chapter 5 Flashcards
What is the purpose , advantage and disadvantages of a microphone
Purpose
- accepts sound input or human voice into a computer system.
- a voice recognition system can convert sound to text.
Advantages
- faster to speak using a microphone than typing
- hands free ( you can do other activities at the same time )
Disadvantages
- the recognition rate of spoken words can be low if there is background noise.
- sound files require more storage than text files.
What is the purpose, advantages and disadvantages of a mouse
Purpose
- used to control the cursor on a visual display unit.
- uses built in sensors to detect movements and send corresponding signals back to the computer.
- includes buttons used to make selections on the screen.
Advantages
- easy to use and requires little or no training.
- quicker to select menus and icons to using a keyboard.
Disadvantages
- experienced users to find it slow compared to using “hot keys”.
- need a flat surface (additional surface) to function properly.
What is the purpose, advantages and disadvantages of a graphics digitiser
Purpose
- allows a user to hand-draw images, which are captured by the computer.
- consists of a flat electronic sensitive surface and a stylus pen.
Advantages
- more natural to draw diagrams with a stylus than with a mouse.
- using a stylus produces more accurate and detailed drawings.
Disadvantages
- not suitable for selecting menus and pointing at menu items.
- more expensive than a mouse.
What is the purpose, advantages and disadvantages of a touchscreen ?
Purpose
-Looks similar to normal computer screens, with a touch sensitive surface.
- when the screen is touched the position is calculated as a (x,y)
Co- ordinate.
Advantages
- user does not require much ICT competence compared to using a keyboard.
- users can select and enter options much faster than using a keyboard.
Disadvantages
- limited number of options are available on screen.
- screens can become dirty quickly.
What is the purpose, advantages and disadvantages of a speaker.
Purpose
- allows sound to be outputted.
- may be internal or external speaker.
- in addition to the hardware, a sound card needs to be fitted inside the computer.
Advantages
- useful for visually impaired users: text or figures can be spoken by the computer.
- natural way to communicate with users
Disadvantages
- external speakers require additional desk space compared to using headphones.
- speakers can distract other users in the same office who are doing other tasks.
What is the purpose, advantages and disadvantages of a laser printer ?
Purpose
- a laser beam is used to scan the image of the page to be printed into a drum by building a pattern of static electricity.
- this attracts toners ( printer ink ) to reproduce the page.
Advantages
- faster to print in bulk compared to an ink jet printer
- produces a high-quality test and graphic output
Disadvantages
- colour laser printers are expensive to purchase and use.
- because they are non-impact printers, multipart stationary cannot be used.
What is the purpose, advantages and disadvantages of a 3D printer ?
Purpose
- gradually prints a solid 3D object one layer at a time.
Advantages
- time taken to produce and object is much faster than conventional methods.
- can print on a variety of surfaces e.g plastic, metal, ceramic.
Disadvantages
- Limited form of printing as it can only print a prototype ( not full scale ).
- non - economical for large scale manufacturing.
What is the purpose, advantages and disadvantages of a hard disc drive ?
Purpose
- consists of a number of rigid discs stacked on a spindle and enclosed in a sealed unit.
- formatting a disc divides the surface area not a number of tracks and sectors.
- as the discs rotate at high speeds the read/write heads move back and forth across the surface.
Advantages
- the cost per gigabyte is cheaper than the other forms of external storage.
- storage capacity is much greater compared to solid-state storage devices.
Disadvantages
- due to moving parts such as read/write heads, they are prone to breaking down.
- access speeds are slower than ‘flash’ memory devices.
What is the CPU ?
The CPU, central processing unit is the processor or ‘brains’ of the computer. this is where data is processed and calculations take place.
The CPU processes programs and data using the fetch execute cycle.
What is the fetch-execute cycle
a computer program that locates a program instruction from memory , decodes the instructionand carries out the action required this process is then repeated for the rest of the program instructions.
what is the role of the control unit
- decides which instruction to carry out next
- fetches it from memory
- decodes the instruction and executes (or obeys) the instruction
- repeats the process (fetch-execute cycle)
what is the role of the arithmetic and logic unit ( ALU )
- carries out arithmetic calculations e.g. addition, multipaction, subtraction, division.
- performs logical comparisons to assist with decision making by using the opperators AND,OR and NOT.
what is the of the immediate access store
( IAS ) ?
- stores all programs and data temporarily while they are in use
- during the fetch execute cycle, instructions are fetched from their specific storage location in the IAS using an adress
- each memory location has a unique address assigned to it.
what is the role of the program counter (PC) during the fetch execute cycle ?
Stores the address of the next instruction to be executed
what is the purpose of the memory adress register during the fetch execute cycle ?
the address of the current instruction or data being executed is temporarily stored in the MAR.
