We can use semaphores to limit access to resources. In the following example, both threads need access to a printer and a SPI port. The binary semaphore sPrint provides mutual exclusive access to the printer, and the binary semaphore sSPI provides mutual exclusive access to the SPI port. The following scenario has a serious flaw:
a) Describe the sequence of events that would lead to the condition where both threads are stuck forever.
b) How could you change the above program to prevent the deadlock?