CP386 FINAL EXAM REVIEW for 14th DEC 2025 Operating System Wilfrid Laurier University

CP386 FINAL EXAM REVIEW for 14th DEC 2025 Operating
System Wilfrid Laurier University




CP386 Final Exam Review
Chapter 6
• Bounded-buffer memory
o Counter set to 0
o Incremented by the producer after produces new buffer
o Decremented by the consumer after it consumes a buffer
o Producer




o Consumer




• Race condition

, o When 2 processes try to manipulate the count variable concurrently
o Synchronization prevents race condition, in order to ensure that only one
process at a time is manipulating the variable
• Critical Section
o Where processes may be changing common variables, updating tables, writing to
files etc
o Solutions to Critical section Problem
▪ Mutual exclusion - When 1 process is in critical section, no other may be
in its critical section
▪ Progress – If no process is in critical section and there exist a process that
wish to enter their critical section, then that process will be selected
▪ Bounded Waiting

, • Petersons Solution (KNOW THE PSEUDOCODE)
o 2 variables are used
▪ Int turn; - Indicates whose turn it is to enter the critical section
▪ Boolean flag[2] – indicates if a process is ready to enter the critical
section
o Not guaranteed to work on modern computer architectures




• Memory Barriers
o When a memory barrier is performed, the system ensures that all loads and
stores are completed before any subsequent load or store operations are
performed
o Strongly ordered - where a memory modification on one processor is
immediately visible to all other processors.
o Weakly ordered - where modifications to memory on one processor may not be
immediately visible to other processors