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Tribhuvan university > CSIT - 2065 Syllabus > Software Engineering > Old Questions > 2068(II)

Software Engineering - Old Questions

Syllabus Notes Old Questions Unit Wise Questions Question Bank

10. Differentiate between interface specification and behavioral specification.

6 marks | Asked in 2068(II)

Interface Specification

Large systems are decomposed into subsystems with well-defined interfaces between these subsystems. Specification of subsystem interfaces allows independent development of the different subsystem. Subsystem make use of other subsystem, so an essential part of specification is to define subsystem. Once the interface are agreed and defined, the subsystem can then be designed and implemented independently. Subsystem interface are often defined as a set of object or component.

Three types of interface may have to be defined:

1. Procedural interface: Used for calling the existing programs by the new programs.

2. Data Structure: Provide data passing from one sub-system to another.

3. Data representation: Ordering of bits to match with the existing system.

Formal notations are an effective technique for interface specification.

Behavioral specification

The simple algebraic technique can be used to describe interfaces where the object state changing depending on the previous operation result. Where this condition holds we say it the behavior properties of system. The specification which is used to specify such type of system property is called behavioral specification.

The object state of the subsystem changes on the result of operations in the object or while interacting with other sub-system objects. The changes of the state of object is called behavioral characteristics of the system. The behavioral state of the formal specification is represented by model-based approach and is expressed as a state model.

Basic types of behavioral specification:

1. Abstract model specifications: defines operations in terms of well-defined mathematical model.

2. Algebraic specifications: defines operations by a collection of equivalence relations.

3. State transition specification: defines operations in terms of states and transitions.

4. Axiomatic specifications: defines operations by logical assertions.