PPT Slide
Using semaphores in SOS
- Semaphores are used to create critical sections around SOS kernel code that uses shared data, such as:
- Accessing the process table in SelectProcessToRun().
- Accessing the disk request queue in DiskIO(), ScheduleDisk() and the disk interrupt handler.
Monitors
- Monitors are an example of synchronization added to a programming language, rather than having to be explicitly programmed via system calls.
- Monitors fit naturally into languages that support modular/abstract data types.
- This type of monitor is not something you connect to the video adapter of a computer!