Real Time Processing

It is also called as interactive mode or Direct mode. This system makes the user to have
direct contact with the computer through his terminal. It is an alternative approach to an on-line
processing system. Here the data is processed, the instant it occurs. There is no delay between
the time data is available, and the time it is processed.

The term real time refers to the technique of updating files transactions date immediately
after the event to which it relates occurs. This is in distinction to batch processing which
processes related data to batches of pre-defined periods of time. Real time systems are basically
on-line systems with one specially in inquiry processing. The response of the system to the
inquiry itself is used to control the activity. An on-line production data collection system that
simply accepts input and utilities it for payroll and costing purposes cannot be termed real-time,
but if, on the other hand, the system is designed to provide immediate information to monitor the
production processes, it is a real time system.

Special Features

(a) Program is always under execution.(b) It produces output to control, direct or affect the outcome of an ongoing activity or
process.
(c) In this method, the control is exercise during the actual functioning.
(d) It is meant exclusively to perform one task.
(e) It is like an online system with; title constraints on response time availability.
(f) It is called a real time system because it has to give results based on dead lines which
are imposed by the real world outside.
(g) The data which has to be produced by the systems has to be in such a less time, that they can
influence the external events which are based on this data.

Thus the response of a real time system is one type of feedback control system. The
response time would naturally differ from one activity to another. If the example, it is the
launching of a space vehicle, the response time should be in split second whereas in business
situation even a few minutes of response time may be alright. Online updating in real time
usually leads to transaction as a by-product. For example, the updating in real time a customer's
order may lead to such transactions as dispatch noted and purchase requests, etc. Real time
systems offer accountants and others in business a chance to fulfill the potential of the computer
as a tool of management.

Guided Missile System

Real Time Processing is suitable in the following type of business operations:
i. Wholesale supplier and manufacture - Availability of stocks.
j. Airline - Flight seat availability.
k. Manufacturing - Status of production orders.
l. Process Control.

Space Craft Control.

Real time systems usually operate in multi-programming and multi-processing: This
increases both availability and reliability of the system. CPU's in real time system should possess
the, capability of what is known as program interrupts. These are temporarily stoppage or halts in
the execution of a program so that more urgent messages can be handled on priority. It may be
worth noting that some computers systems are dedicated to real time operations and others are

designed to operate in both batch and real time modes so that they can also serve as stand by unit
to each other.