week 15 - interconectedness Flashcards
why are interconnected systems needed
To allow different components of the computer to communicate with each other
An interconection structure must support:
- Memory to Processor
- Processor to Memory
- I/O to Processor
- Processor to I/O
- I/O to or from Memory
Types of interconection structure
- Bus
- Point to Point
Bus interconection
- a shared pathway connecting two or more components
- signal transmited by one device is evalable for any other device on the bus
- only one device can tranmit at a time
- bus consists of multiple lines (bus width)
Data lines
to provide a path for moving data among system modules
- key factor in determening system performance
Address lines
to designate the source or destination of the data on the data line
- bus width determing maximum memory capasity
Control lines
to control the access to and the use of the data and address lines
- the data and address lines are shared by all components, there must be a means of controlling their use
-Command signals: Specify operation to be performed
-Timing Signals: Validity of data and address information
Bus operations
If one module wishes to send data to another:
-Obtain the use of the bus
-Transfer the data via the bus
If one module wishes to request data from another module
-Obtain the use of the bus
-Transfer a request to other module over the appropriate control and address lines
Point-to-point Interconnection
contempary system have started to use point to point interconnection
- quicker because you dont have to wait for a bus to be free to use the system
- every component has there own bus
system bus
most comon bus it is the bus that connects the different components of the computer together
