Operating system components--Part II.

Abstract

To summarize this discussion, let us look at a prototype, a capsule scenario in an OS. You make a process creation request on your local timeshare system. The long-term scheduler queues up this request, and eventually creates the corresponding process. Your process takes its turns executing, scheduled by the short-term scheduler. You request a tape drive to retrieve some archived data you need, and thus invoke the resource manager. You use the file manager to access the archived data. You use the I/O system to interact with the application program and to print the reports. The memory manager is swapping pages of your data and program between main memory and secondary memory. The dispatcher in the kernel is loading your process context into the CPU when your process is next on the execute list. The interrupt handler in the kernel is servicing interrupt requests, such as those made when you do I/O to the tape. The concurrency control in the kernel is coordinating your updating and spooled printing activities. So, your process is invoking activities throughout the various layers of the OS. Most of the time, you are unaware of these many varied activities.