1. A parking lot, any time, at most, can accommodate 30 vehicles, when less than 30 car parking, can immediately enter the outside, or need to wait in the outside, if a vehicle is regarded as a process, please answer the following questions,
(1) the use of wait, these concurrent signal operation management process, should be how to define the signal? Write the signal of the initial value and various values, the meaning of semaphores (2) according to the definition of semaphore, shall implement wait, signal operation to fill in the following program suitable location. To ensure the process can correctly execute concurrently,