Ambient pressure concept of pressure becomes irrelevant, and it is undefined at a gravitational singularity. The SI unit of pressure is the pascal (Pa), which is a very small unit relative to atmospheric pressure on Earth, so kilopascals (kPa) are more commonly used in this context. The ambient atmospheric pressure at sea level is not constant: it varies with the weather, but averages around 100 kPa. In fields such as meteorology and underwater diving, it is common to see ambient pressure expressed in bar or millibar. One bar is 100 kPa or approximately ambient pressure at sea level. Ambient pressure may in
BBC Micro expansion unit MHz. It runs the non-graphical Panos operating system. Various programming languages are available including C, FORTRAN, Lisp, and Pascal, in addition to a version of BBC BASIC. The processor comes with 1 MB of RAM as standard. The processor is also inside the "Acorn Cambridge Workstation" this time using 10 MHz parts and 4 MB of RAM, sold as part of the Acorn Business Computer line. The Universal Second Processor Unit was an adapter for BBC Master internal co-processor boards, to allow them to be used as external co-processors. It comprised a power supply, interface logic and a connector that