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.
what is the purpose of the memory data register ( MDR )
This register will temporarily store data being fetched from or written to the CPU
what are registers in the cpu ?
they are high speed memory locations , each used for specific purposes.
what is the purpose of the instruction register ( IR ) in the fetch execute cycle ?
Temporarily stores the current instruction to be decoded and then executed.
what is the purpose of the accumulator during the fetch execute cycle ?
When calculations take place on data, the results are initially stored in the accumulator before being transferred and stored in main memory.
what three factors influence the speed of processing ?
Clock Speed
* This measures the number of instruction cycles the CPU can deal with in a second
* Measured in GHZ (higher number the better)
cache
* Temporarily stores frequently used instructions and data.
* It is quicker to search cache memory than RAM thus increasing processor speed.
processor core
* Can be defined as a single processor.
* More advanced CPUs contain more than one which will increase their ability to run many programs at the same time e.g. quad core processor has 4 processors.
what is high defintion ( HD ) storage media
- HD storage media uses laser technology to store and retrieve data at high datatransfer speeds to and from optical discs.
- they can store over 50Gb of data ( more than ten times the amount that can stored on a DVD )
- instead of a red laser ( used on a DVD ) they use a blue laser, which burns much smaller pits into the surface.
- this increases the densisty and therefore the storage capcacity.
what are solid state-state storage device ?
- A solid-state storage device is refered to as “flash memory” and non-volatile.
- USB memory sticks are a type of solid state storage.
- they are compact portable have a large storage capacity and do not require a software driver to be installed. ( and so are described as “plug and play” devices )
what are memory cards ?
- These are electronic flash memory storage devices.
- they are used in a range of digital devices, inluding mobile phones, digital cameras and MP4 players.
- For example , in mobile phones a SIM ( subscriber identity module ) card is used to store data.
what are smart cards ?
- bank cards use a form of flash memory known as “chip and pin”.
- cards contain a small embedded integrated circuit (IC) , which allows data to be written to and read from the card using a smart card reader.
what is RAM ( random access memory )
- memory can be read from and written to (volatile)
- stored programmes and data that the user is curently using
- the size of the RAM can influence the speed of the processor (the larger the RAM capacity the faster the processor)
what is the ROM ( read only memory )
- memory can be read from but not written to (non-volotile)
- used to store programs that the computer frequently required e.g the booting up program runs automatically for windows when u turn it on.
