“11 An Ada program is composed of one or more program units. Program units may be subprograms (which define executable algorithms), packages (which define collections of entities), task units (which define concurrent computations), protected units (which define operations for the coordinated sharing of data between tasks), or generic units (which define parameterized forms of packages and subprograms). Each program unit normally consists of two parts: a specification, containing the information that must be visible to other units, and a body, containing the implementation details, which need not be visible to other units. Most program units can be compiled separately.” —:Ada-Europe’s Ada Reference Manual: Introduction: Language Summary See legal information

    “18 A task unit is the basic unit for defining a task whose sequence of actions may be executed concurrently with those of other tasks. Such tasks may be implemented on multicomputers, multiprocessors, or with interleaved execution on a single processor. A task unit may define either a single executing task or a task type permitting the creation of any number of similar tasks.” —:Ada-Europe’s Ada Reference Manual: Introduction: Language Summary See legal information

    “28 Certain statements are associated with concurrent execution. A delay statement delays the execution of a task for a specified duration or until a specified time. An entry call statement is written as a procedure call statement; it requests an operation on a task or on a protected object, blocking the caller until the operation can be performed. A called task may accept an entry call by executing a corresponding accept statement, which specifies the actions then to be performed as part of the rendezvous with the calling task. An entry call on a protected object is processed when the corresponding entry barrier evaluates to true, whereupon the body of the entry is executed. The requeue statement permits the provision of a service as a number of related activities with preference control. One form of the select statement allows a selective wait for one of several alternative rendezvous. Other forms of the select statement allow conditional or timed entry calls and the asynchronous transfer of control in response to some triggering event.” —:Ada-Europe’s Ada Reference Manual: Introduction: Language Summary See legal information

    “34/2 Composite types allow definitions of structured objects with related components. The composite types in the language include arrays and records. An array is an object with indexed components of the same type. A record is an object with named components of possibly different types. Task and protected types are also forms of composite types. The array types String, Wide_String, and Wide_Wide_String are predefined.” —:Ada-Europe’s Ada Reference Manual: Introduction: Language Summary See legal information

    “35 Record, task, and protected types may have special components called discriminants which parameterize the type. Variant record structures that depend on the values of discriminants can be defined within a record type.” —:Ada-Europe’s Ada Reference Manual: Introduction: Language Summary See legal information