Describe parallel protocols PCI, PCI-X.
1 Answer


PCI stands for Peripheral Component Interconnect/Interface bus.

It is popular for higher bandwidth processor independent which can function as peripheral bus. It is introduced by Intel in 90‟s

It is 32 bit local bus and extended up to 64 bit by processor it requires.

It has high speed I/O subsystem performance.

The PCI is designed to meet economically the i/o requirement of modern system.

It supports ten i/o devices and provides 3 types of synchronous parallel interface

It has two versions: 32 bit (33 MHz) ,64 bit (66 MHz)

The data transfer rate for synchronous is 132 mbps and for asynchronous it is 528 mbps.

The PCI driver can access hardware automatically or by programmer can assign address.

The automatic detection and assignment of addresses of various devices simplifies the addition and removal of the system peripheral.

PCI is designed to support variety of microprocessor best configuration including single and multi-processing system.


It is an extension of PCI bus and supports 64 bit, 100MHz transfer.

PCI – X is revised to double the maximum clock speed to improve the data exchange transfer between processor and peripherals.

The data exchange rate is 1.06 gbps.

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