Type of Computer Bus

Type of computer bus-

What is computer bus?

Inside computers, there area unit several internal parts. so as for these parts to speak with one another, they create use of wires that area unit called a ‘bus’.

A bus could be a common pathway through that data flows from one computer part to a different. This pathway is employed for communication functions and it’s established between 2 or additional computer parts. we have a tendency to area unit reaching to check totally different computer bus architectures that area unit found in computers.

Functions of Buses in Computers-

Summary of functions of buses in computers-

1. Information sharing –  Each form of buses found terribly} very computer transfer information between the computer peripherals connected to it. The buses transfer or send information either among the serial or parallel technique of data transfer.

This allows for the exchange of 1, 2, four or even eight bytes of data at a time. (A memory board unit could also be a cluster of eight bits). Buses square measure classified depending on what proportion bits they will move at constant time, that suggests that we’ve 8-bit, 16-bit, 32-bit or even 64-bit buses.

2. Addressing –  A bus has address lines, that match those of the processor. this allows information to be sent to or from specific memory locations.

3. Power –  A bus provides power to varied peripherals connected to it.

4. Temporal order –  The bus provides a system clock signal to synchronize the peripherals attached to it with the rest of the system.

Bus Technology-

Computers have 2 main bus types:

1. System Bus:-  This can be the bus that connects the C.P.U. to the most memory of the motherboard. System bus is additionally known as front-side bus, memory bus, native bus or host bus.
2. Several I O buses-  (I O short for input/output), connect varied peripheral devices to the C.P.U.. These devices hook up with the system bus through a ‘bridge’ enforced within the processor’s chipset. alternative names for the I/O bus embrace “expansion bus”, “external bus” or “host bus”.

Expansion Bus varieties-

These area unit a number of the common growth bus varieties that are utilized in computers:

1. ISA –  The industry normal design.
2. EISA –  Extended the industry normal design.
3. MCA –  Micro Channel Architecture
4. VESA –  Video natural philosophy Standards Association.
5. PCI –  Peripheral part Interconnect specific (PCI-X) Computer.
6. MCIA –  Pc Memory Card The industry Association (Also known as PC bus).
7.  AGP –  Accelerated Graphics Port interface – little computer Systems Interface.

ISA Bus – The eight Bit and sixteen Bit ISA Bus. This is the foremost common form of early growth bus, that was designed to be used within the original IBM computer. The IBM PC-XT used associate 8-bit bus style. this suggests that the information transfers happen in 8-bit chunks (i.e., one computer memory unit at a time) across the bus. The ISA bus ran at a clock speed of four.77 MHz. For the 80286-based IBM PC-AT, associate improved bus style, that may transfer 16-bits of knowledge at a time, was proclaimed. The 16-bit version of the ISA bus is typically called the AT bus (AT-Advanced Technology). The improved AT bus additionally provided a complete of twenty four address lines, that allowed 16MB of memory to be addressed . The AT bus was backward compatible with its 8-bit precursor and allowed 8-bit cards to be utilized in 16-bit growth slots. When it initial appeared, the 8-bit ISA bus ran at a speed of four.77MHZ – identical speed because the processor. enhancements done over the years eventually created the AT bus ran at a clock speed of 8MHz. Comparison Between eight and sixteen Bit ISA Bus- Comparison of 8-bit, & 16-bit ISA Bus as utilized in Early Computers. Comparison of 8-bit bus- 8-Bit ISA card (XT-Bus) 8-bit information interface 4.77 megahertz bus 16-bit ISA Bus- 1. 16-Bit ISA (AT –Bus card) 2. 16-bit information interface. 3. 8-MHZ bus . 4. 62-pin connecto. 5. 62-pin connecter. 6. 36-pin AT extension affiliation       EISA Bus- EISA (Extended trade normal Architecture) This is a bus technology developed by a bunch of manufactures as another to MCA. The bus design was designed to use a thirty two-bit information path and provided 32 address lines, giving access to 4GB of memory. Like the MCA, EISA offered a disk-based setup for the cards, however it still ran at 8MHz so as for it to be compatible with ISA. MCA (Micro Channel Architecture)- IBM developed this bus as a replacement for ISA after they designed the PS/2 computer in 1987. The bus offered variety of technical enhancements over the ISA bus. for example, the MCA ran at a quicker speed of 10MHz and supported either 16-bit or 32-bit information. It additionally supported bus mastering – a technology that placed a mini-processor on every growth card. These mini-processors controlled a lot of of the information transfer permitting the C.P.U. to try to to alternative tasks. One advantage of MCA was that the plug-in cards were computer code configurable; this suggests that they needed minimal  intervention by the user once configuring. The MCA growth bus didn’t support ISA cards and IBM set to charge alternative makers royalties to be used of the technology. This created it unpopular  and it’s currently obsolete technology. VESA Bus- It was additionally called the native bus or the VESA-Local bus. VESA (Video natural philosophy Standards Association) was fabricated to assist standardize PCs video specifications, therefore resolution the matter of proprietary technology wherever totally different makers were trying to develop their own buses. The VL Bus provided 32-bit information path and ran at twenty five or thirty three megahertz. It ran at identical clock frequency because the host C.P.U.. Features of the VESA native bus card:-

1. 32-bit interface.
2. 62/36-pin connecter.
3. 90+20 pin VESA native bus extension.

PCI (Peripheral part Interconnect)- Peripheral part Interconnect (PCI) is one among the most recent developments in bus design and is that the current normal for laptop growth cards. Intel developed and launched it because the growth bus for the Pentium processor in 1993. it’s an area bus like VESA, that is, it connects the central processing unit, memory, and peripherals to a wider, quicker information pathway. PCI supports each 32-bit and 64-bit information width; it’s compatible with 486s and Pentiums. The bus information breadth is adequate the processor, like a thirty two-bit processor would have a 32 bit PCI bus, and operates at 33MHz. PCMCIA Bus- PCMCIA bus interface cards translate the information from the PCMCIA bus to a different bus, and contrariwise. they’re accustomed connect 2 otherwise incompatible buses. PCMCIA is Associate in Nursing signifier for the non-public storage Card Association, the organization that develops and maintains standards for PCMCIA cards. AGP (Accelerated Graphics Port)- The need for prime quality and really quick performance of video on computers crystal rectifier to the event of the Accelerated Graphics Port (AGP). The AGP port connects to the central processing unit and operates at the speed of the processor bus. This suggests that video data is distributed a lot of quickly to the cardboard for process. The AGP uses the most laptop memory to carry 3D pictures. In effect, this offers the AGP video card a limiteless quantity of video memory. to hurry up the information transfer, Intel designed the port as an on the spot path to the PC’s main memory. Data transfer rate ranges from 264 Mbps to 528mbps, 800 Mbps up to one.5 Gbps. AGP instrumentation is known by its brown color. small computer system interface (Small computing system Interface) SCSI Bus- SCSI (pronounced SKUH-zee and generally informally referred to as “scuzzy”), the little computing system Interface, could be a set of yankee National Standards Institute (ANSI) normal electronic interfaces that enable personal computers (PCs) to speak with peripheral hardware like disk drives, tape drives, CD-ROM … Short for little computing system Interface, a interface normal utilized by Apple Macintosh computers, PCs and OS systems for attaching peripheral devices to a desktop.