Pressure measurement because atmospheric pressure is always changing and the reference in this case is fixed at 1 bar. To produce an absolute pressure sensor, the manufacturer seals a high vacuum behind the sensing diaphragm. If the process-pressure connection of an absolute-pressure transmitter is open to the air, it will read the actual barometric pressure. The SI unit for pressure is the pascal (Pa), equal to one newton per square metre (N·m or kg·m·s). This special name for the unit was added in 1971; before that, pressure in SI was expressed in units such as N·m. When indicated, the zero reference is
IP Pascal libraries present an idealized API for each function that applies, such as files and extended operating system functions, graphics, midi and sound, etc. The whole collection forms the basis for an implementation on each operating system and machine that IP Pascal appears on. The two important differences between IP Pascal and many other languages that have simply been mated with portable graphics libraries are that: IP modules can also be created that are system independent, and rely only on the porting platform modules. The result is that IP Pascal is very highly portable. Example: The standard "hello world" program is