Comp111 - Quiz 1
Oct 4, 2017 - closed book
Please fill in the blanks. Each blank is worth 5 points.
There are several reasonable answers for some of the blanks; choose one.
Blanks with the same number have the same answer.
- The operating system sends ________1________ to processes to inform them of state changes. To send one of these, a process can use the ________2________ system call.
- When measuring the time for a process, ________3________ time is the time spent inside the process, while ________4________ time is time spent inside the operating system on behalf of the process.
- When creating a child process, the only difference between the
parent and the child is the return value of
________5________. When a child exits, it returns a(n)
________6________ to the parent. If the parent does not
read this, the child becomes a(n) ________7________.
- Signal handlers can be called at any time, so that they utilize a different ________8________ to avoid confusion. This allows signals to interrupt ________9________ as well as the regular program. This is called "signal stacking".
dup on a file descriptor makes a copy of it in the ________10________ that is not open.
- A pipe is a(n) ________11________ represented by an array of two file ________12________, one for the write side and one for the read side.
- The point of write buffering is to minimize ________13_________ according to one of three buffering strategies. For example, ________14________ buffering calls a system call only when the user types ________15________. One can force a system call by ________16________ the buffer. If one exec's another program before doing this, pending output is ________17________.
- The reason we pass so many pointers to system calls as type _______18________ is that the operating system has no reason to know the real type.
- To glue the output of process one to the input of process two, one opens a pipe and dups its write side to the file descriptor with number ________19________ on process one, and dups its read side to the file descriptor with number ________20________ on process two.
- (Extra credit) The only difference between the memory maps for a thread and a process is that a thread has its own ________21________.