Chapter 3 - System Architecture Flashcards
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What is hardware
A component with physical presence
what is an example of hardware
- printer
- hard-drive
- mouse
- monitor
What is software
Programs that control the hardware
What is an example of software
- Operating System
- Word Processors
- Games
How does a simple computer system function
Input -> Process -> Output
What happens at the input stage of a simple computer system
Where input data that is converted into the computer’s internal representation. This is done by the input devices like keyboard and mouse
What does the control unit do?
- Controls and monitors the hardware (e.g. Printer)
- Controls the input and output of data so that the signals go to the right place at the right time
- Controls the flow of data in the CPU
What does the Arithmetic and Logic Unit do?
- Arithmetic part – performs calculations on the data
2. Logic part – deals with logic and comparisons (e.g. Is one value greater than another)
What does Immediate Access Storage do?
This holds the data and instructions needed by the control unit.
What is the purpose of the CPU?
The main purpose of the CPU is to fetch, decode and execute tasks and the CPU cycles through this pattern.
What are some processing tasks of the CPU?
Processing task involve: searching, sorting, calculations, making decisions.
What is secondary storage, and why is it useful?
Anything that stores data other than in temporary storage (RAM). This is useful as RAM is volatile so this can be used as a back-up
What can secondary storage also be known as?
External memory, auxiliary storage
What are the main uses of secondary storage?
Storing programs and data Backing up data Adding additional storage Transferring files between computers Shared network storage
Give examples of places where magnetic secondary storage is used?
Disks
Tapes
Explain magnetic secondary storage?
Stores it magnetically, depending on which way it’s positioned it will represent a 1 or a 0
Give examples of places where optical storage is used?
CD
DVD
blue-ray disks
What is optical storage?
Used the reflection of a laser to see if it is a 1 or a 0
Give examples of where solid state storage is used?
USB
Flash card
What is solid state storage?
Stores data in an electric circuit
What is a bus?
A bus is simply a set of wires along which data can be transmitted.
What does an address bus carry?
An internal channel from the CPU to memory across which the addresses of data (not the data) are transmitted
What does a data bus carry?
An internal channel that carries data between a computer’s central processing unit and its random-access memory.
What does a control bus carry?
The control bus carries commands from the CPU and returns status signals from the devices.
What is Von Neumann Architecture?
Von Neumann architecture is when there is one central memory store that holds two things:
The Instruction
The Data
What does the FETCH command do?
The CPU fetches the data from its location.
What does the DECODE command do?
The CPU has its individual command set and it uses this to work out what data is being used.
What does the EXECUTE command do?
The instruction is carried out.
What is meant by direct access?
The exact file can be accessed directly without having to read any other files
What is meant by sequential access?
Each bit of data needs to be read before the required data is located
Give an advantage of a magnetic disk
Rewritable
Give a disadvantage of a magnetic disk
Easily damaged
Low storage capacity
Noisy
Give an advantage of magnetic tape
Large storage capacity for the size of the tape
Give a disadvantage of magnetic tape
Not very durable
Needs to be protected
Give an advantage of optical storage
Quite long lasting
Portable
Give a disadvantage of optical storage
Expensive
Only readable
Easily scratched
Give an advantage of a solid state disk
Fast start up time
Silent
Durable
Give a disadvantage of a solid state disk
Expensive
Limited storage capacity
Information can only be erased and written about 100,000 times
Give an advantage of a USB pen drive
Durable
Portable
Give a disadvantage of a USB pen drive
Easy to lose
