Discuss the major differences, advantages and disadvantages between bus I/O and channel I/O
Solution
Bus I/O:
A bus is a shared communication link between I/O to processor and to memory.
Advantages of Bus I/O system:
1. Easy to add additional devices
2. Peripherals can be moved between computer systems with same bus standards.
3. Low cost
Disadvantages of Bus I/O system:
1. The bus speed is liminted by lenght of the bus and Number of devices connected to the bus.
2.The bandwidth of the bus can limit the maximum I/O throughput.
3. It creates a communication bottleneck.
Channel I/O: It is a high performance architecture which can be implemented as I/o controller or DMA controller
In this architecture, a separate low cost processor is used to handle I/O tasks.
Therefore communication is initiated by CPU and the data transfer is carried out by the controller without intervention of the CPU.
Thus the major advantage is imporvement of overall processor performance by making CPU busy with other processes.
Channel I/o provides high data transfer rate.
It takes few cycles for each transfer.
Disadvantages are:
DMA controller is required hence more expensive.
In this method synchronization mechanism is required to acheive correctness of data transfered.
Differences:
Bus I/o: low cost
Channel I/O : Expensive
Bus I/O: low data rate
Channel I/O: high data rate of transmission
Bus I/O: Shared bus among devices,
Channel I/O: separate processor is required to carry out data transmission
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Discuss the major differences- advantages and disadvantages between bu.docx
1. Discuss the major differences, advantages and disadvantages between bus I/O and channel I/O
Solution
Bus I/O:
A bus is a shared communication link between I/O to processor and to memory.
Advantages of Bus I/O system:
1. Easy to add additional devices
2. Peripherals can be moved between computer systems with same bus standards.
3. Low cost
Disadvantages of Bus I/O system:
1. The bus speed is liminted by lenght of the bus and Number of devices connected to the bus.
2.The bandwidth of the bus can limit the maximum I/O throughput.
3. It creates a communication bottleneck.
Channel I/O: It is a high performance architecture which can be implemented as I/o controller
or DMA controller
In this architecture, a separate low cost processor is used to handle I/O tasks.
Therefore communication is initiated by CPU and the data transfer is carried out by the
controller without intervention of the CPU.
Thus the major advantage is imporvement of overall processor performance by making CPU
busy with other processes.
Channel I/o provides high data transfer rate.
2. It takes few cycles for each transfer.
Disadvantages are:
DMA controller is required hence more expensive.
In this method synchronization mechanism is required to acheive correctness of data transfered.
Differences:
Bus I/o: low cost
Channel I/O : Expensive
Bus I/O: low data rate
Channel I/O: high data rate of transmission
Bus I/O: Shared bus among devices,
Channel I/O: separate processor is required to carry out data transmission
