If process Pi is executing in its critical section, then no other processes can be
executing in their critical sections

Peterson’s Solution is a hardware-based solution to the critical-sectio

Peterson’s Solution is … to be synchronized

in Peterson’s Solution we have … shared variables

in Peterson’s Solution entry section of process i contains

in Peterson’s Solution entry section of process j contains

in Peterson’s Solution exit section of process i contains

in Peterson’s Solution exit section of process j contains

to solve critical section problem Disabling interrupts is efficient on multiprocessor systems

Atomic =

in hardware synchronization solutions are based on the idea of locking

we have a shared lock variable which can take one of the two values, 0 or 1

The Test_and_Set takes a shared variable called offset that represent the lock status and return its
original value and then set the variable to true which means the lock is disabled

in Test_and_Set entry section

in Test_and_set exit section

CompareAndSwap software instruction is also an atomic instruction

CompareAndSwap always returns the new value of the lock variable

in CompareAndSwap entry section

in CompareAndSwap exit section

Simplest is mutex lock, boolean variable indicating if lock is available or not