The VHSIC Hardware Description Language (VHDL) provides a standard machine processable notation for describing hardware. VHDL is the result of a collaborative effort between IBM, Intermetrics, and Texas Instruments; sponsored by the Very High Speed Integrated Cir cuits (VHSIC) program office of the Department of Defense, beginning in 1981. Today it is an IEEE standard (1076-1987), and several simulators and other automated support tools for it are available commercially. By providing a standard notation for describing hardware, especially in the early stages of the hardware design process, VHDL is expected to reduce both the time lag and the cost involved in building new systems and upgrading existing ones. VHDL is the result of an evolutionary approach to language devel opment starting with high level hardware description languages existing in 1981. It has a decidedly programming language flavor, resulting both from the orientation of hardware languages of that time, and from a ma jor requirement that VHDL use Ada constructs wherever appropriate. During the 1980's there has been an increasing current of research into high level specification languages for systems, particularly in the software area, and new methods of utilizing specifications in systems de velopment. This activity is worldwide and includes, for example, object oriented design, various rigorous development methods, mathematical verification, and synthesis from high level specifications. VAL (VHDL Annotation Language) is a simple further step in the evolution of hardware description languages in the direction of applying new methods that have developed since VHDL was designed."

The VHSIC Hardware Description Language (VHDL) provides a standard machine processable notation for describing hardware. VHDL is the result of a collaborative effort between IBM, Intermetrics, and Texas Instruments; sponsored by the Very High Speed Integrated Cir cuits (VHSIC) program office of the Department of Defense, beginning in 1981. Today it is an IEEE standard (1076-1987), and several simulators and other automated support tools for it are available commercially. By providing a standard notation for describing hardware, especially in the early stages of the hardware design process, VHDL is expected to reduce both the time lag and the cost involved in building new systems and upgrading existing ones. VHDL is the result of an evolutionary approach to language devel opment starting with high level hardware description languages existing in 1981. It has a decidedly programming language flavor, resulting both from the orientation of hardware languages of that time, and from a ma jor requirement that VHDL use Ada constructs wherever appropriate. During the 1980's there has been an increasing current of research into high level specification languages for systems, particularly in the software area, and new methods of utilizing specifications in systems de velopment. This activity is worldwide and includes, for example, object oriented design, various rigorous development methods, mathematical verification, and synthesis from high level specifications. VAL (VHDL Annotation Language) is a simple further step in the evolution of hardware description languages in the direction of applying new methods that have developed since VHDL was designed."

This reference manual of ANNA is another volume addressed to the ADA community. ANNA is a language extension of ADA to include facilities for formally specifying the intended behavior of ADA programs. It is designed to meet a perceived need to augment ADA with precise machine-processable annotations so that well established formal methods of specification and documentation can be applied to ADA programs. The current ANNA design includes annotations of all ADA constructs except tasking. Similar extensions for formal specification can be made to other Algol-like languages such as Pascal, PL/1, Concurrent Pascal, and Modula; essentially, these extensions would be subsets of ANNA. The design of ANNA was undertaken from the beginning with four principal considerations: 1. Constructing annotations should be easy for the ADA programmer and should depend as much as possible on notation and concepts of ADA. 2. ANNA should possess language features that are widely used in the specification and documentation of programs. 3. ANNA should provide a framework within which the various established theories of formally specifying programs may be applied to ADA. 4. Annotations should be equally well suited for different possible applications during the life cycle of a program. Such applications include not only testing, debugging and formal verification of a finished program, but also specification of program parts during the earlier stages of requirements analysis and program design.