For each implementation there is a library package called System which includes the definitions of certain configuration-dependent characteristics. Values of type Name are the names of alternative machine configurations handled by the implementation. The largest possible number of binary digits in the mantissa of machine numbers of a user-defined ordinary fixed point type. Tick A period in seconds approximating the real time interval during which the value of Calendar.
Clock remains constant.
The number of bits per storage element. The number of bits per word. Address represents machine addresses capable of addressing individual storage elements. An implementation may add additional implementation-defined declarations to package System and its children. However, it is usually better for the implementation to provide additional functionality via implementation-defined children of System.