In the language of computers, the term buses actually refer to the system present within the hardware of the computer. This system is helpful in moving the data and without these buses; the computer can do calculations but lack the capability of moving the resulting information to any of the output device. There are various categories and types of computer buses and they are also known as peripheral component interconnect or PCI. The main function of the computer buses is of data sharing, addressing, power, and timing etc.
There are three main types of computer buses such as address buses, data buses, and control signals. The address buses actually convey an address provided by the CPU from one place to other within the computer. On the other hand, the data buses are convey information from one unit to another and is also called as bi-directional bus which means that the information can be conveyed in either direction. The third main type of computer buses is of control signal, which plays a vital role in carrying the control signals from ALU to the memory and back from the memory to the ALU and finally to the output unit.
Besides the main types of computer buses, there are some expansion types of computer buses. These expansion types generally include ISA, EISA, MCA, VESA, PCI, PCMCIA, AGP, and SCSI. The most commonly used type of expansion bus is of ISA and it was originally patterned to for usage in the IBM pc. Micro channel architecture or MCA is the type of computer bus that was basically formulated by IBM and as a substitute for ISA. A large number of technical improvements were made in this type of computer bus and the plug-in cards used in it were software configurable. However, this computer bus was unable to support the ISA cards which made it quite unpopular.
EISA or extended industry standard architecture was formulated by a group of producers and was considered to be a great alternate to MCA. The expansion slots of the EISA were two times deeper than that of ISA slot. But, the disadvantage of this type of computer bus was that it was very expensive and was generally found on network servers and work stations having high-ends. Local bus also named as VESA bus was actually devised to help the video specifications of the standardized PCs. In addition, the slots of VESA bus consisted of an additional set of connectors and hence the cards were bigger.
The peripheral component internet or PCI is considered to be one of the most recent growths in bus architecture and is the present standard for the expansion cards of PC. In addition, it also supports bus mastering and has the processing ability which helps the CPU to spend less time in processing data. The accelerated graphic port or AGP is the type of computer bus which is quite helpful in rendering enhanced quality and quick performance of videos on computers. this bus has the capability to hold almost 3D images by using the main memory of the PC.