Flashcards in Chapter 2 - Computer Hardware Deck (31)
What are the two components of the CPU?
- arithmetic and logic unit carries out all of the arithmetic and logic calculations
- control unit uses electrical signals to control the flow of data within the CPU
What is the function of the CPU?
1. Fetch the instructions stored in memory
2. Decode the instruction to find out what processing to do
3. Execute the instruction
How do you increase the performance of a CPU?
Increase the clock speed, cache size and number of cores.
What is clock speed?
Number of cycles of the fetch execute cycle completed in one second, determined by an electronic clock chip, measure in Gigahertz GHz.
What is multiple processor core?
More than one CPU working together to process more data simultaneously.
What is hardware?
Physical components of a computer system, anything that can be seen or touched.
What is a disadvantage of a multiple processor core?
More complicated operating systems are needed to manage them.
What is RAM?
Random access memory which is volatile (data is lost when power is turned off)
What is ROM?
Read only memory which is non volatile
When can the computer access and change RAM + ROM
It can access RAM any time
It can never access ROM (programmed during manufacture
What does RAM + ROM store?
RAM: Programs and data being used by the computer
ROM: instructions and data required to start up the computer (boot sequence + boot loader)
What does RAM + ROM contain?
Ram: operating system
Rom: boot program
Is Ram + ROM large or small?
Ram: Large 4GB+
Rom: smal 1/2MB
What is the purpose of a CPU?
It carries out all the processing in a computer.
What is virtual memory?
It I part of the hard rice an is used as an extension to RAM.
What is cache memory?
Very expensive memory which has access times similar to CPU (fast)
Why is there a need for cache memory?
The CPU cannot access main memory at the same speed as re processor clock chip - transferring data from main memory (RAM) to the CPU causes delays. Data that is in use is transferred to cache memory to make access to it faster.
How does the CPU interact with cache memory?
CPU check cache to see if data needed is there a it requests data
If data is not in cache, CPU requests data from RAM
Data requested from main memory is copied to cache
Data is sent to CPU
How does RAM affect the performance of a computer?
Adding RAM reduces the use of virtual memory and improves the performance of a computer.
This is because data is passed between RAM and virtual memory and access to virtual memory is slower.
When is virtual memory used?
When the computer does not have enough RAM to hold all the data and programs required.
Why is data represented in binary form in computers?
Because it is easy to tell the state of the switch on (0) or off (1).
What is flash memory?
A type of ROM which can be rewritten, it is used as a portable medium for toeing and transferring data.
Why is there a need for secondary storage?
Because secondary storage is non volatile and there is a need to store data and programs when the power is switched off.
What are three examples of secondary storage and what are they?
Magnetic hard disk: store operating system, installed programs and data
Optical disk: excellent for transferring files or distributing software
Flash memory/solid state: consumes little power
What 5 things should be considered when choosing secondary storage?
Capacity, speed, portability, durability and reliability
Which is most expensive of all secondary storage?
Magnetic hard drive
Why is there a need for input and output devices?
Computers process data we supply as inputs to provide us with required outputs, if a computer cannot accept inputs an provide outputs then it is of little value
Examples of input devices?
Keyboard ( used for data entry)
Mouse (controls a pointer on the screen)
Touch screen (allows user to interact directly with icons to control the device)
Bar code scanner (reads light which is reflected back to identify a product)
Examples of output devices?
Monitor (displays text, image, video)
Printer ( produce shard copy on paper)
Speaker (produces sound)
Actuator (creates physical movements in response to computer commands)