Software product development through re-entrants

Concurrent systems which run several processes at the same time feel the need to share common resources simultaneously.
Re-entrant is a generic term that includes resources such as functions, routines, or programs which allow the ‘same copy of instructions’ in memory to be shared by multiple users’ .Thus the ‘same copy’ may be re-entered by one user, while it is already in use by the other. A very important component called Re-entrant Interrupt Handler facilitates the entire process of software product development.
Re-entrant interrupt handler
It is logical to question that while the program is in use by one user, a sudden interruption by the other may risk the data that the former is working with. This anomaly in offshore online software development is prevented by the interrupt handler.
When the program is interrupted by other user, data associated with previous user is saved. The user seeking interruption can then work on the new set of values it has.
When the previous user again regains control of the process, the saved data is recovered and the execution continues from the point it last interrupted without any concern of the other user having used the same program for software and its development.
Requisite attributes of a re-entrant
A must have attributes for any custom software company are-

* A re-entrant must not hold any static or globally declared values beforehand.

* Each process calling the re entrant must work on its own set of unique values.

* The process must not incorporate changes in the code while working with the routine.


To put forward an example of re-entrant in Real time processing, an online computerised reservation system invariably requires its audience to access the same kind of information, like the Time Table (program) at the same time. These different passengers (processes) are located in different parts of the world. Under the circumstances, it is typical for any custom software company to make use of re-entrant.