Brief USB Overview and USB History

USB Overview In the past, connecting multiple peripheral devices to computer has been a real problem. There were too many different port types (serial port, parallel port, PS/2 etc.) and their use imposes limitations such as no hot-pluggability and automatic configuration. There are very limited number of ways to attach the peripheral devices in the original IBM PC implementation due to the requirements in terms of non-shareable IRQ lines and I/O address space. The main reason that Universal Serial Bus was implemented to provide a replacement for those legacy ports on a computer to make the addition of the peripheral devices quick and easy for end user.