BUS Review
You have seen some of the main bus technologies and bus configurations, and how plug-and-play
works.
Information is carried within and in or out of a PC on a bus.
A system bus connects the CPU with RAM, whereas an I/O bus connects the CPU with other components in a computer.
A bus contains data lines, for transmitting data, address lines for determining where the data should go, and controllines for directing data transfers.
The width andthe speed of a bus determines its transmission capacity.
There are many variations in the speed atwhich different buses operate.
The ISA bus is the I/O bus that was designed for the original IBM PC.
Since its development, several other bus standards have evolved, includingthe EISA and the MCA standards.
Local bus development speeded up data transmission by enabling specific devices
to access the CPU directly.Two of the best local buses to be developed are the VESA local bus and the PCI bus.
Most recently, bus development has produced very fast serial buses, the most well known of these being the USB and the IEEE 1394.
Most modern PCs contain a number of different buses, organized hierarchically.
The bus hierarchy consists of the processor bus, the (optional) cache bus, the memory bus, the local I/O bus, and the standard I/O bus.
Multiple bus configurations can be complex, and the motherboard chipset is important for coordinating communications between different buses.
Intel has devised a bus configuration model that divides the functions of the chipset into two distinct parts.
The so-called Northbridge chip essentially deals with the CPU and memory, while the Southbridge chip mainly deals with peripherals and the standard I/O bus (usually an ISA bus).
The aim of the plug-and-play system is to reduce or eliminate the need for user intervention in the configuration of a PC.
With a plug-and-play system, the user should be able to simply plug in any new device and it will configure itself automatically.
The three essentials of the plug-and-play system are a plug-and-play operating system, plug-and-play hardware, and a plug-and-play BIOS (basic input/output system).
Windows 2000 is an example of a plug-and-play operating system.
The three types of plug-in cards that can be configured automatically at present are PC Cards,
PCI cards, and PnP ISA cards.
The plug-and-play BIOS plays an essential part in the automatic configuration of devices, through a process of enumeration, arbitration, and configuration.
Quiz Basic Elecricity Techonology HTML