Advantages of PCI bus | Disadvantages of PCI bus
This page covers advantages and disadvantages of PCI bus. It mentions benefits or advantages of PCI and drawbacks or disadvantages of PCI (Peripheral Component Interconnect).
What is PCI bus?
• PCI bus is developed by Intel (later PCI-SIG) with the ideas from previous bus architectures such as ISA (Industry Standard Architecture) and VLB (VESA Local Bus).
• This conventional PCI is a local computer bus used to attach hardware devices in a computer.
• Attached devices are either in the form of ICs fitted on motherboard or an expansion card which fits into slot.
• Devices on the bus master appears to be connected directly whose addresses are assigned in the address space of the processor.
• PCI is a parallel bus which is synchronous to single bus clock.
As shown in the figure, multiple devices can communicate simultaneously in parallel. Initially PCI bus was developed with 33 MHz speed and later on 66 MHz and 133 MHz have been developed.
The windows 95 feature called "Plug and Play" utilizes PCI bus concept. Following benefits make it one of the fastest I/O bus.
Benefits or advantages of PCI bus
Following are the benefits or advantages of PCI bus:
➨It uses 64 bit addressing scheme.
➨It works on synchronous bus architecture.
➨It supports linear burst mode data transfer.
➨It offers large bandwidth and higher speed.
➨It supports full bus mastering.
➨It supports plug and play.
➨PCI uses shared bus topology in order to allow for communication among different devices on the single bus. Once a device becomes master, it can use PCI bus to communicate with CPU or memory.
Drawbacks or disadvantages of PCI bus
Following are the drawbacks or disadvantages of PCI bus:
➨It supports maximum five devices on single PCI bus and hence requires PCI to PCI bridge to support more than 5.
➨It is a parallel bus and hence it has bandwidth limitations. Moreover available bandwidth is shared by all the devices on single PCI bus.
➨PCI bus can not be easily scaled up in frequency or scaled down in voltage.
➨PCI clock frequency is inadequate.
➨Lack of isochronous data transfer.
➨It does not support advanced power management.
➨PCI does not support built in hot plugging or hot swapping of peripherals.