Universal Serial Bus

In information technology, Universal Serial Bus (USB) is a serial bus standard to interface devices to a host computer. USB was intended to allow many peripherals to be connected using a single consistent interface socket and to get better the plug-and-play capabilities by allowing hot exchange, that is, by allowing devices to be connected and disconnected without rebooting the computer or rotating off the device. Other suitable features comprise providing power to low-consumption devices without the require for an external power provide and allowing many devices to be used without requiring manufacturer exact, individual device drivers to be installed.

USB is intended to replace many legacy varieties of serial and similar ports. USB can connect computer peripherals such as mouse, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal media players, and flash drives. For many of those devices USB has become the standard connection method.

Industry Standard Architecture

The most common bus in the PC world, ISA stands for Industry Standard Architecture, and different many uses of the word "standard", in this case it in fact fits. The ISA bus is still a foundation in even the latest computers, despite the fact that it is mainly unchanged since it was prolonged to 16 bits in 1984! The ISA bus finally became a bottleneck to performance and was augmented with extra high-speed buses, but ISA persists because of the truly huge base of obtainable peripherals using the standard. Also, there are still many devices for which the ISA's speed is more than enough, and will be for a number of times to come

The choices made in important the main characteristics of the ISA bus--its width and speed--can be seen by looking at the processors with which it was balancing on early machines. The unique ISA bus on the IBM PC was 8 bits wide, shiny the 8 bit data width of the Intel 8088 processor's system bus, and ran at 4.77 MHz, again, the speed of the first 8088s. In 1984 the IBM AT was introduced using the Intel 80286; at the moment the bus was doubled to 16 bits (the 80286's data bus width) and increased to 8 MHz (the maximum speed of the original AT, which came in 6 MHz and 8 MHz versions).