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
Pascal (programming language) R. Hoare. Pascal programs start with the program keyword with a list of external file descriptors as parameters<ref name="iso/iec 7185:1990 6.10">Pascal ISO 7185:1990 6.10</ref> (not required in Turbo Pascal etc.); then follows the main block bracketed by the begin and end keywords. Semicolons separate statements, and the full stop (i.e., a period) ends the whole program (or "unit"). Letter case is ignored in Pascal source. Here is an example of the source code in use for a very simple "Hello world" program: A type in Pascal, and in several other popular programming languages, defines a variable in such a way