Question

question about operating system,thank you

1 List two most important differences between an embedded system and a time-sharing system
that have impact on the design of the corresponding OS.

2 What is the reason of using resource abstraction? Give an example of an abstract resource
and an example for the corresponding physical resource?

Answer 1

1 List two most important differences between an embedded system and a time-sharing system
that have impact on the design of the corresponding OS.

The time-sharing operating system is used to perform general tasks. Embedded system tends to have a very specific task.

In time sharing system, multiple jobs are executed at the same time by switching between the tasks. The switching is very fast so that the users can not realize that system is being shared.They can interact with the program while running.This means that the user can give instructions to the system directly through input devices  and the result will be obtained through output devices. Mutliprogramming or maultitasking is implemented using time -sharing operating system to switch jobs. For example while we are using MS Word, many small threads are running like spelling checking and grammar checking. so the time sharing operating system gives time to all these small tasks and the other application so that the system behave smoothly.

Embedded systems are real time operating systems. It is used in tasks that needs to be completed within a certain time period.It employs strict timing constraints to drive execution of tasks in an external environment. Accuracy of the result and timely response is very important in the case of embedded system. Otherwise the system will fail.These are used in applications which involve control devices like medical imaging system, automobile-engine fuel injection system, weapon system etc.

The time sharing operating system enables sharing of resources among several applications. In embedded system, one application is involved.

Time sharing operating system requires less CPU time.It employs a strategic CPU scheduling and multiprogramming to give each user a little amount of time shared system.

Embedded systems are not recognized as computers. They are hidden within the devices. Instead of using familiar computer interfaces like keyboard, mouse etc, embedded systems use unusual interfaces like sensors, actuators etc.

2 What is the reason of using resource abstraction? Give an example of an abstract resource
and an example for the corresponding physical resource?

Resource abstraction means hiding the details of how the hardware operates, thereby making the computer hardware relatively easy to use for a software professional. Resource abstraction provides an abstract model of the operation of hardware components and generalizes hardware behavior. It also limits the flexibility in which the hardware can be manipulated. It also provides a convenient working environment for application programmers by hiding some of details of the hardware, so that he can put his focus on coding the application.

For example operating system can implement resource abstraction by providing a single abstract disk interface which is same for hard disk and floppy disk. This is helpful for the programmer as he needs to learn only the disk abstraction provided by the operating system instead of learning the details of both hardware interfaces.