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Comparison between real time and time sharing operating system

Protection and security

• Protection refers to a mechanism for controlling the access of program s processes, or users to the resources defined by computer system.

• The concept of protection came with the advent of multiprogramming where several processes compete for the use of CPU.

• the purpose was to confine each users program to its assigned areaof memory so that the programs cannot interface and harm each other.

• Protection in main memory is particularly important because of address translation. The purpose of protection is to allow concurrently running process to share the common physical address space.

• Protection also ensure that only process that have gained proper authorization from the operating system can operate on memory segment , the CPU, files and other resources.

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Defination of OS(operating system) and its concepts

What do you mean by operating system? Definition : An operating system is a program that act as an interface between the user of a computer and the Computer hardware. Operating system is a first program that gets loaded into the memory through a process called booting. Concepts of operating system : · The purpose of operating system is to provide an environment in which a user can execute program in a convenient and efficient manner. · Operating system is an integrated set of program that ma...

Multi Level Queue Scheduling (MLQ)

Multi Level Queue Scheduling (MLQ) · Multilevel queue scheduling classifies the processes according to their types for example, a multilevel queue scheduling algorithm makes a common. · In this scheduling ready queue is divided into various queue that are called sub queues. A subqueue is a distinct operational queue · The process are permanently assigned to subqueues, generally based on some property of the process such as memory size,priority or process type · Each subqueue has its process sucheduling algorithm. For example interactive process at the foreground may use round robin scheduling while batch jobs at the background may use the FCFS method · For example, consider a system with four different queues 1. ...

Classification of Operating System

Classification of operating systems The operating systems may be classified into different types depending upon the nature of interaction between the user and his/her program. The various types of operating system are : 1. 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 Distributed system Multi threading operating system Single user operating system · ...

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. ...