MCQ IN COMPUTER SCIENCE & ENGINEERING

Detailed explanation-1: -Data flow diagrams represent systems by use of a sparse number of symbols. Systems processes are symbolized by circles, entities external to the system which interact with the system are represented by rectangles, and data stores are denoted by an open ended rectangle.

Detailed explanation-2: -An external entity sends or receives data from the system. It is represented by a rectangle.

Detailed explanation-3: -In DFD, an input/output receiver is generally represented by a rectangle.

Detailed explanation-4: -Circle (process)-it is used to distinguish between data input and data that comes from a process. Two parallel lines (data store)-a repository of data that is to be stored for use by one or more processes; may be as simple as a buffer or a queue or as sophisticated as a relational database.

Detailed explanation-5: -An internal entity is an entity (i.e., person, place, or thing) within the system that transforms data. 2 Internal entities include, for example, sales clerks (persons), departments (places), and computers (things). Therefore, physical DFDs specify where, how, and by whom a system’s processes are accomplished.