Computer Processor Info page.    
A special register, or memory location, in the arithmetic and logic unit of the computer processor. It is used to hold the result of a calculation temporarily or to store data that is being transferred.
  •   BUS
The electrical pathway through which a computer processor communicates with some of its parts and/or peripherals. Physically, a bus is a set of parallel tracks that can carry digital signals; it may take the form of copper tracks laid down on the computer's printed circuit boards(PCBs), or of an external cable or connection.
A computer typically has three internal buses laid down on its main circuit board: a data bus, which carries data between the components of the computer; an address bus, which selects the route to be followed by any particular data item travelling along the data bus; and a control bus, which is used to decide whether data is written to or read from the data bus. An external expansion busis used for linking the computer processor to peripheral devices, such as modems and printers.
  • Parallel Processing
Emerging computer technology that allows more than one computation at the same time. Although in the 1980s this technology enabled only a small number of computer processor units to work in parallel, in theory thousands or millions of processors could be used at the same time.
Parallel processing, which involves breaking down computations into small parts and performing thousands of them simultaneously, rather than in a linear sequence, offers the prospect of a vast improvement in working speed for certain repetitive applications.