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

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...

Multi Programming Operating System

Multi programming system · Multi programming operating system allows multiple users to execute multiple programs using a single CPU concurrently i.e. at the same time. · In multiprogramming several process are kept in the main memory and CPU execute all these processes concurrently. It means, the CPU immediately switches from one process to next that are ready to get executed · In such an operating system when one process start process start performing the instructions from several programs at the same time. · Rather, it means that there are number program available to CPU and that portion of one is executed, then segment of another and so on ...

Time Sharing System and its Requirements

Time sharing system · Time sharing refers to the allocation of computer resources in a time dependent fashion to several program simultaneously · A time sharing system has many user terminals that are connected to same computer simultaneously. Using these terminal, different users can work on a system at the same time · Thus, it uses multi programming with a special CPU scheduling among all the last one, and then again beginning from the first one · In time sharing system, the CPU time is divided among all the users on schedule basis. · It release the CPU under any of the following three conditions: 1. When the allotted time slice expires. 2. ...

Multitasking System

Multitasking system · Technically , multitasking is same as multi programming · In a multitasking operating system, s single user can execute multiple programs at the same time · We can also say, multitasking is the system capability to work on more than one job or process at the same time. · It means that whenever a job needs to perform I/O operation, the cpu can be used for execting some other job diagram of multi tasking · There are two type of multitasking : 1. ...

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...

Easytolearn

Search This Blog