A time sharing system is to be designed to support a large number of users. List all the considerations which influence the choice of the time slice. Justify each consideration.
Answers
A time sharing system or Multitasking system allows many users to share the computer resources simultaneously. In other words, time sharing refers to the allocation of computer resources in time slots to several programs simultaneously. For example a mainframe computer that has many users logged on to it. Each user uses the resources of the mainframe -i.e. memory, CPU etc. The users feel that they are exclusive user of the CPU, even though this is not possible with one CPU i.e. shared among different users.
A time sharing machine is designed when the number of computers are greater than the number of CPU available, which shall execute the processes. In such cases the computers present should be served properly, so that cases like computers sitting idle, and other one getting processes done with low priority, may not arise.
For solving such issues there are two solutions, one is the priority scheduling, and the other is the Round-robin scheduling algorithm.
- In priority scheduling, the computer with the highest priority is made available to the CPU.
- In Round-robin algorithm, all the computers connected get an equal time slice, to get CPU for there processes, to get processed.