What are the basic difference between online and real time operating system?

Answer 1

In a simple timeshare operating system all processes receive a time "slice", meaning that a process can run for a specified amount of time, typically measured in fractions of a second.

In a simple realtime operating system, all processes are assigned a process "priority" If a process is ready to run and it has a higher priority than other processes, the process has control of the CPU until the process gets to a point that it is no longer "ready". That can mean that the process is waiting for I/O or for the completion of some event. If multiple process with higher and equal priority are "ready", the CPU is typically shared between them, using some kind of timesharing.

Most of todays operating systems use a blending of the concepts.

Answer 2

Well... to easy the answer Multitasking is just a technique involved in building an OS Thus any OS must have some kinds of multitasking. example Both Windows OS & MAC OS use Preemptive Multitasking but also there is another type of multitasking known as Cooperative. Thus these 2 are the most commonly used multitasking techniques really.

(you can Google for more about their differences)

Going back to your actual question, you should now have noticed that Multitasking is a technique used in an OS development. another term "Real time" comes almost always with an "Operating system (OS)" because the operating systems built by multitasking Technique are almost always Real time based if that form of multitasking has at least some or more of these parts:

a) Scheduler: its primary role is to Dispatch every task within a certain given time and then go to the next task etc...

b) Kernel (aka Context switching) This is the core of modern operating systems, Kernel here ensures that as each task (process) as it is being finishes its time to run every single peripherals that task used such as memory, register, etc... are restored back to their default values ready to be used by the next task and Kernel actual saves the data of every single task here even though it was suspended. Kernel does a lot more though. but this is His basic or primary role.

In Embedded systems Multitasking the above parts are a must for any OS.

Thus the facts that a given OS is a real time really means nothing more than saying that each task has got its own defined time. Thus a task must run at a certain given time and end at another time and this time a task uses is always known and is periodic which means a task is being run at a certain known time no matter what happen at time "t1" a certain given task "x" will be run and later at time "t2" will finish and since this can happen forever without any obstruction this is called a Real time.

I think you now hopefully understand a basic idea behind a Real time OS and Multitasking :))

Nshuti Olivier.

Mechatronics

(Massey University Albany)

Answer 3

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