Computing - Computer Organisation and Architecture
What is a computer system?
Any device that can take a set of inputs and process them into useful outputs.
What are the three key stages in a computer system?
What are the 4 main components of a motherboard?
- CPU
- Main memory
- Address, control and data buses
- I/O controllers
How do components of a motherboard communicate with one another?
Using a bus.
What are the three types of bus?
- Control
- Data
- Address
Why can’t external devices be connected directly to the processor?
Because the external devices are produced by different manufacturers so they will work differently.
Why are I/O controllers neccessary in a motherboard?
So that the motherboard can act as an interface between the device and the computer.
What is the main function of an I/O controller?
Converts signals from peripheral devices into a format the computer can accept, and vice versa.
What burden does an I/O controller take from the CPU?
The I/O controller manages data flow to and from a device so the CPU can get on with other tasks.
What is the control bus?
Sends control signals to and from the processor to I/O controllers and memory.
What is the data bus?
Sends data between different components in the CPU.
What is the address bus?
Sends memory addressed from the processor to components.
What does uni-lateral mean?
Data can only sent one way.
What does bi-lateral mean?
Data can be sent both ways.
What is a memory read control signal?
Cause data from the addressed location to be placed on the data bus.
What is a memory write control signal?
Cause data on the data bus to be written into the address location.
What is a bus request control signal?
Indicates that a device is requesting the use of the data bus.
What is a bus grant control signal?
Indicates that the CPU has granted access to the data bus.
Who sends a bus grant control signal?
CPU.
What is a clock signal?
Used to synchronise operations in the CPU.
What is a bus in hardware?
A series of wires that transfer data signals between internal components.
What are the common number of lines in a bus?
- 8
- 16
- 32
- 64
What is a line in a bus?
One individual wire in a bus.
What is a word in computing?
Chunks of equal units in memory.
Words can be accessed by?
A unique memory address.
What would be the memory capacity in bytes of a machine with an $8$-line address bus and a word length of $8$ bits?
What are the common number of words in memory?
- 8 bits
- 16 bits
- 32 bits
- 64 bits
What type of direction does a data bus have?
It is bi-drectional.
What makes a data bus bi-directional?
Data can be sent both ways along the bus.
What is the “width” of a data bus?
The amount of lines/wires it contains.
If you have a 16 line bus and a 32 bit word, how many memory access and data transfer operations will there be?
2 operations.
How does bus width affect overall system performance?
Because it affects how many operations there have to be to retrieve memory.
What type of direction is an address bus?
Uni-directional.
What affect oes the width of an address bus have on the system.
It determines the number of maximum possible memory addresses of the system.