Types of buses in Microcomputer
Types of buses:
SCSI: The small computer system interface (SCSI) standard is defined by the American National Standards Institute (ANSI) for connecting daisy-chaining multiple I/O devices, such as scanners, hard disks, and CD-ROMs, to the microcomputer. SCSI is a standard interface for all types of microcomputers. It is used in Macintosh, RISC workstations, and minicomputers, as well as higher-end IBM-compatible computers.
There are currently several different computer buses on the market that are designed for microcomputers. Some of the computer BUS are ISA, MCA, EISA, VESA PCI, FireWire, USB, and PCI Express. Universal serial bus (USB) and PC Express are covered in more detail because they are more advanced than other buses.
The industry-standard architecture (ISA) bus was introduced by IBM for the IBM PC using an 8088 microprocessor. The ISA bus has an 8-bit data bus and 20 address
lines at a clock speed of 8 MHz. The PC AT type uses the 80,286 processor which has a 16-bit data bus and 24-bit address lines and is compatible with the PC.
Microchannel Architecture Bus: The microchannel architecture (MCA) bus was introduced by IBM in 1987 for its PS/2 microcomputer. The MCA bus is a 32-bit bus that can transfer four bytes of data at a time and runs at a 10 MHz clock speed. It also supports 16-bit data transfer and has 32-bit address lines. Microchannel architecture was so expensive the non-IBM vendors developed a comparable but less expensive solution called the EISA bus.
EISA Bus: The extended ISA (EISA) bus is a 32-bit bus that also supports 8- and 16-bit data transfer bus architectures. EISA runs at 8-MHz clock speeds and has a 32-bit address line.
VESA Bus: The video electronics standard association (VESA) bus, which is also called a video local bus (VL-BUS), is a standard interface between the computer and its expansion.
As applications became more graphically intensive, the VESA bus was introduced to maximize the throughput of video graphics memory. The VESA bus provides fast data flow between stations and can transfer up to 132 Mbps.
PCI Bus: The peripheral component interconnects (PCI) bus was developed by Intel Corporation. PCI bus technology includes a 32-/64-bit bus that runs at a 33/66 MHz clock speed. PCI offers many advantages for connections to hubs, routers, and network interface cards (NIC). In particular, PCI provides more bandwidth: up to 1 gigabit per second as needed by these hardware components.
The PCI bus was designed to improve the bandwidth and decrease latency in computer systems. Current versions of the PCI bus support data rates of 1056 Mbps and can be upgraded to 4224 Mbps. The PCI bus can support up to 16 slots or devices in the motherboard. Most suppliers of ATM (asynchronous transfer mode) and 100BaseT NICs offer a PCI interface for their products. The PCI bus can be expanded to support a 64-bit data bus.