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What does copy-on-write mean in relation to a child process and its parent?
The idea behind a copy-on-write is that when a parent process creates a child process then both of these processes initially will share the same pages in memory and these shared pages will be marked as copy-on-write which means that if any of these processes will try to modify the shared pages then only a copy of these …
This means that the parent and child will share the parent address space until one of them does a write, at which point the memory will be physically copied to the child. This eliminates unneeded copies when exec ing a new process.
What is not shared between parent and child process?
the system implementation determine whether the processes can share a physical copy of the text region. Difference between parent and child process : Neither process can access the variables of the other process. Process locks, text locks, and data locks are not inherited by the child process.
When does a parent or child modify a page?
Whenever a process (parent or child) modifies a page, a separate copy of that particular page alone is made for that process (parent or child) which performed the modification. This process will then use the newly copied page rather than the shared one in all future references.
Both processes share files that the parent had open at the time of the fork , and the file table reference count for those files is one greater than it had been.
Which is the parent process in C-Fork ( )?
Child process: executes child code, and calls exit (). This prevents us from looping and creating more children than intended. Parent process: Bypasses the if (fork () == 0) statement’s body and steps through the loop, spawning additional children as specified.
Any pending alarms are cleared in the child process. In case of COW , parent process and child process share the same process address space, until one of the process don’t write , if some process write, then we create for copying of address space.