What You Need to Know About Bus Drivers

In computer architecture, a bus is a subsystem which is used to transfer data between different components of the computer. The bus makes it possible for all the components of the system to connect to the CPU and the memory of the system. A bus transfers information which is changed into electrical pulses, and each bus will represent either a 1 or 0 bit. A bus can be many various sizes, and the size will depend on how many bits are transferred. Common bus sizes in reference to bits can be four, eight, twelve, sixteen, and more up to one hundred and twenty eight bits.

These common bus terms can be useful for PC users who are not experienced in the subject:

The Bus Speed is the speed of bus, and this is calculated in MegaHertz (MHz). This refers to the data traveling speed.

The bus capacity refers to what the bus can transfer or carry. This is derived by taking both sides of the bus and multiplying by the bus speed. This equation can be affected by other factors which may cause it to slow down.

The Internal Bus is the bus that is inside the processor. This bus does work such as transferring the data, any instructions, and any other essential information between internal PC components.

The External Bus is a bus located outside of the processor, but is still inside the PC. This bus performs tasks like data transfer that occurs between various computer components.

The Data Bus is the one which does the actual transferring and carrying of the data. These buses can be internal or external, and internal buses move data inside the processor, while external buses will move data between the processor and the computer memory.

Address buses are made up of information concerning the destination where the data is being sent.

Multiplexing occurs when a data bus and an address bus are combined to form one single bus.

ISA stands for Industry Standard Architecture, and these buses were developed by IBM and released in 1981. The first ISA buses were only eight bit, and they carried a data speed of only 4.77 MHz. In 1984, ISA buses were released that carried sixteen bits, and had a speed of 8.3 MHz.

MCA stands for Micro Channel Architecture, and these thirty two bit buses were introduced in 1987. These buses were considered a failure and other manufacturers never accepted them.

Extended Industry Standard Architecture, also called EISA, buses are thirty two bit and have a speed of 8.3 MHz. These buses were created by a coalition of competitors which included Epson, Hewlett Packard, NEC, Olivetti, Tandy, WYSE, AST Research, Compaq, and Zenith Data Systems. The EISA buses were a response to the failed MCA bus. EISA buses are backwards compatible with ISA buses, and can automatically configure and set up the adaptor card.

VESA Local Bus stands for Video Electronics Standards Association Local Bus. This bus was first released in 1992 for Intel. The bus can transfer thirty two bits, and has a speed of 33 MHz.

Peripheral Component Interconnect buses, also called PCI buses, were first introduced by Intel in the year 1993. There are two versions of PCI buses available, both a thirty two bit 33 MHz version, and a sixty four bit 66 MHz version. PCI buses offer support for Plug and Play devices, and this has made them popular. PCI buses will automatically check for any errors that occur during the data transfer, and they also use a burst mode, which makes it possible to send many data sets to one single address at the very same time, which increases the bus speeds. These buses are one of the most commonly used computer buses in the world today.

USB buses, also called Universal Serial Buses, are one of the latest buses to become available. USB buses are external buses, and were first available in the year 1996. Many companies combined efforts to help develop USB buses, and these companies include Microsoft, Compaq, IBM, DEC, Intern, NEC and Northern Telcom. USB buses have the ability to transfer up to twelve megabits per second, and with a single IRQ can support up to one hundred and twenty seven devices.

The USB driver stack for Windows XP and Windows 200 are completely different. For a Windows 2000 system to support USB, a new parallel driver stack is required. This new stack will contain Usbport.sys, Usbhub20.sys and Usbehci.sys. Hccoin.dll, which is a host controller-specific coinstaller, is also included to make sure that the correct Windows Update installation is provided in the Windows 2000 scenario.