If Charles Babbage is to be regarded as the father of modern day computer technology, then surely the Countess Augusta Ada Lovelace, after whom this new language is named, must be remembered as its midwife. It was she, the daughter of England's poet Lord Byron, who translated the work of the Italian mathematician L.F. Menabrea, attaching her own scientific commentaries on the dissimilarities between the difference engine and the analytical engine. It was Lady Lovelace, the great lady of computers, who delivered the notes and loosely organized writings of Babbage, with her own invaluable amendments, to a world not quite ready to receive them. The Ada language effort has employed hundreds, if not thousands, of minds and a healthy sum of money since its conception. Ada was fostered by the High Order Language Working Group (HOLWG), chartered by the U.S. Department of Defense in January of 1975 with the overall objective of developing a systematic approach to improved use of software by the military. One would think the Pentagon an unlikely foster parent for a new computer language. Regardless of its lineage, the question that begs asking is, of course - Why? The answer is by no means a simple one, but some brief background may help to clarify the matter. At present, the Department of Defense is the largest software consumer on earth, employing roughly 400 different computer languages and dialects. The situation, some have commented, is at best untidy.

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The Landscape.- 1: Five Examples.- 1.1 Temperature Conversion.- 1.2 Counting Change.- 1.3 A Better Way to Count Change.- 1.4 Target Practice.- 1.5 Keeping Score.- Dominant Features.- 2: Describing Data.- 2.1 Types.- 2.2 Primitive Types.- 2.3 Array Types.- 3: Describing Computations.- 3.1 Expressions.- 3.2 Assignment Statements.- 3.3 Conditional Statements.- 3.4 Looping Statements.- 4: Subprograms.- 4.1 Subprograms.- 4.2 Calling Statements.- 4.3 Separation of Subprogram Bodies.- 4.4 Overloading of Subprograms.- 5: Packages.- 5.1 The Visible Information.- 5.2 Making Use of the Visible Information.- 5.3 Providing Operations Over Data.- 5.4 Private Information.- 5.5 Summary.- 6: General Program Structure.- 6.1 Elaboration of Declarations.- 6.2 Nesting and Visibility.- 6.3 Separate Compilation.- 6.4 Using Separate Compilation.- 6.5 Summary.- Specialized Features.- 7: Types Revisited.- 7.1 Record Types.- 7.2 Types with Dynamic Structure.- 7.3 Derived Types.- 7.4 Constraints on Types.- 8: Input and Output.- 8.1 Printing a Price List.- 8.2 Use of Specialized Subprograms.- 8.3 Predefined Packages for Input-Output.- 9: Parallel Processing.- 9.1 Textual Appearance of a Task.- 9.2 Organization of Multiple Tasks.- 9.3 Communications between Tasks.- 9.4 Choosing Among Alternative Entry Calls.- 9.5 Specifying Delays.- 9.6 Interrupting a Task.- 10: Exception Conditions.- 10.1 Introducing Exceptions.- 10.2 Raising and Handling an Exception.- 10.3 Propagation of an Exception.- 10.4 Exceptions Arising During Inter-task Communication.- 11: Utilizing the Implementation.- 11.1 Representing Data.- 11.2 Changing the Representation of Data.- 11.3 Giving Instructions to the Translator.- 11.4 Environment Inquiries.- Perspective.- 12: Summary.