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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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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. ...

Real-time system

R eal-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. R eal-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 ...

Batch Processing Operating System

Batch processing system · Batch processing is one of the oldest method of running the programs · The computer in the past were very large in size and their I/O devices were very different from those that are used today. The job processing was not interactive as it is today. · The user did not interact directly with computer system. · The process scheduling , memory management, file management and I/Omanagement functions are quite simple in batch processing system 1. Process scheduling (i.e. allocation strategy for a processor is typically in order of their arrival i.e. first come first served(FCFS)basis. 2. Memory management is done by divi...

Virtual Machine Architecture

Virtual Machine Architecture A virtual machine can exist as a standalone machine or it can exist within a vApp. A virtual machine is a software computer that, like a physical computer, runs an operating system and applications. The virtual machine consists of a set of specification and configuration files and is backed by the physical resources of a host. Every virtual machine has virtual devices that provide the same functionality as physical hardware are more portable, more secure, and easier to manage. Virtual machines can be standalone, or they can exist within a vApp. A vApp is compound object composed of one or more virtual machines as well as one or more networks. 1. Monolithic architecture 2. Layerd archtecture . 3. Virtual machine architecture 4. Exokernel architecture 5. Client server architecture 6. Micro kernel architecture The following figure ...

Micro kernel architecture

Micro kernel architecture What is Kernel? A kernel is an important part of an OS that manages system resources. It also acts as a bridge between the software and hardware of the computer. It is one of the first program which is loaded on start-up after the bootloader. The Kernel is also responsible for offering secure access to the machine's hardware for various programs. It also decides when and how long a certain application uses specific hardware. What is Microkernel? Microkernel is a software or code which contains the required minimum amount of functions, data, and features to implement an operating system. It provides a minimal number of mechanisms, which is good enough to run the most basic functions of an operating system. It allows other parts of the operating system to be implemented as it does not impose a lot of policies. Microkernels and their user environments are usually implemented in the C++ or C programming languages with a little bit of assembly. Ho...