Computer Architecture

Computer Architecture
Architecture is how things are designed and built, when referring to computers it can be for the circuits within each individual component or the way those components process data, this helps to develop standards making it easier for devices to effectively communicate and work efficiently.

Busses
A bus is a collection of parallel wires which data is transmitted through on a computer, it connects all the computer components to the CPU and only one device can use the bus at any time. Busses consist of two parts, the address bus which indicates where the data will go and the data bus which carries the data on.

For a device to read or write to the buss firstly the address for the device must be placed on the address bus, then the device will know that the data is meant for it and not any other devices on the same bus. The device will also use a clock signal to keep synchronised with the CPU and a read/write signal to indication whether the device to be read from or written to.

The width of the bus determines the maximum data that can be transferred through it at any one time, a 32-bit bus can carry 32 individual bits at any time but no more.

Accelerated Graphics Port (AGP)
AGP is designed around PCI but with a focus on graphical interfaces to improve the performance of 3D graphics, it also features a direct point to point channel to main system memory so that a GPU can use system RAM instead of the cards VRAM.

In order to use AGP the chipset must first support it, the motherboard should have an AGP bus, the OS needs to support it and the graphics card needs to support AGP.

AGP was the successor to PCI for graphical devices as it provided higher bandwidth and direct memory access. The most recent version is AGP 3.5 and has been phased out in preference to PCI Express due to even higher data bandwidth.