CS 3733 Operating Systems, Fall 2004 Midterm Exam Comments

Grade distribution (class average was 79):

• 90-99: 9
• 80-89: 16
• 70-79: 11
• 60-69: 6
• 50-59: 2
• below 50: 1

• There are several correct answers here for some of the parts.
  For example, ready to running can occur when another process leaves the CPU: when it terminates, requests I/O, or a quantum expires.
  Note that a scheduler dispatch is not considered an event. It is the result of an event.
• In Problem 3, the write(fd,"abc",3) always writes 3 bytes atomically as stated in the problem and the other one writes 2 bytes. What happens is determined by the order in which the parent and child execute. You needed to give an explanation involving the file offset stored in the system file table.
• In Problem 4, you need to say which system file table entries are affected. If the function takes a single file descriptor parameter, as in close, this might be obvious. It is not obvious in the other cases.