Skip to main content

Real-time system

 Real-time system

·         In a real time operating system, a job is to be completed within the  rigid time constraints otherwise job loses its meaning.

·         A real time system function correctly only if it returns the correct result within its time constraints

·         Thus, in a  real-time system, the correctness of the  computation not only depends upon the logical correctness of the computation but also upon the time at which the result is produced.

Real-time system

In a real time system various functions like process scheduling, memory management, I/O management and file  management are performed as follows :

1.       Process scheduling . the real time system uses priority based pre-emptive scheduling. each process is assigned a certain level of priority and the process with the highest priority is allocated the processor among those which are in the ready state.

2.       Memory management. In real time system, the processes remain in primary memory for most of the time in order to provide quick response.

3.       I/O device management . time critical device management is main requirement of real time system . it also uses feature like interrupt management and I/O buffering.

4.       File management. In real time system, file management does not aim at efficient utilisation of secondary storage rather main objective is to provide fast access.

        single user operating system  

2.      Multi user operating system 

3.       Batch processing operating system

4.      Multi programming operating system 

5.     Multi tasking operating system 

6.       Multiprocessing operating system

7.       Time sharing operating system

8.     Real time system  

Real-time operating system are categorised into:

1.      Hard real-time systems

2.      Soft real-time systems

 

1.       Hard real time systems complete the critical tasks within the definite interval of constraints. If the critical task is not completed within the time constraints then the hard real time system fails.

Thus, a hard real time system has to complete all the processes within definite deeding and a single miss leads to critical failure

 

2.       Soft real time system are less restrictive in a nature and are not affected the lapse of time interval and do not cause any critical failure.

Soft real time system are used in the area of multimedia, virtual reality


Comparison between soft real time and hard real time system

 

 




 

 

Comments

Post a Comment

Popular posts from this blog

Multi user Operating System

  Multi user operating system ·           In a multi-user operating system, multiple number of user can access different resources of a computer at a same time. ·           The access is provided using a network that consists of various personal computer attached to a mainframe computer system.                                                              diagram of multi -user operating system       ·           The various personal computer can send and receive information to mainframe computer system. ·           The example    of multi-user OS are UNIX, windows 2000,novell netware.            sing...
Post a Comment
Read more

Multilevel Feedback queue scheduling (MFQ)

  Multilevel Feedback queue scheduling (MFQ) ·          Multilevel feedback queue scheduling is an enhancement of multi-levelqueue scheduling. In this scheme, processes can move between the different queue ·          The various processes are separates in different queue on the basis of their CPU Burst Char characteristics ·          If a process consumes a lot of CPU time , it is placed into a lower priority queue. Thus I/O bound and interactive process are placed in the higher priority queue and CPU bound pricesses are in lower priority ·          If a processes waits too long in a lower priority queue it is moved higher priority queue. Such an aging prevents starvation. ·          The top priority queue is given smallest CPU time Quantum ·      ...
Post a Comment
Read more

Multi processing system

  Multi processing system ·           Multi processesor system is the sytem that contain two or more processors or CPUS and has ability to simultaneously execute     several programs. Hence the name multi-processor In such a system, multiple processor share the clock, bus, memory and peripheral devices. ·           A multi processor system is also known as parallel system ·           Multi processor system are categorized into two different types:                single user operating system    2.        Multi user operating system   3.         Batch processing operating system 4.        Multi programming operating system   5.       Multi tasking operating sy...
Post a Comment
Read more

Monolithic Architecture

  Monolithic Architecture Monolith means composed all in one piece. The  Monolithic  application describes a single-tiered  software  application in which different components combined into a single program from a single platform. Components can be: Authorization — responsible for authorizing a user Presentation — responsible for handling HTTP requests and responding with either HTML or JSON/XML (for web services APIs). Business logic — the application’s business logic. Database layer — data access objects responsible for accessing the database. Application integration — integration with other services (e.g. via messaging or REST API). Or integration with any other Data sources. Notification module — responsible for sending email notifications whenever needed. Example for Monolithic Approach Consider an example of Ecommerce application, that authorizes customer, takes an order, check products inventory, authorize payment and ships ordered products. This applicat...
Post a Comment
Read more

Write a note on real time OS.

  Write a note on real time OS. Ans. In real time operating system , job is to be completed within the rigid time constraints otherwise job loses its meaning. A real time system functions correctly only if it return the correct result within its time constraints Thus, in a real tome system , the correctness of the computation not only depends upon the logical correctness of the but also upon the time at which the result is produced. A real time system is often used as a central device in a dedicated applications like fuel-injection system, robotics, air- traffic control, medical imaging systems, systems that control scientific  experiment, industrial control system and weapon systems .  
Post a Comment
Read more