week-5-homework-1

• When I was a grad student at Purdue University, we used to use several different software packages for example for VLSI design or C++ programming running on Sun/HP workstations. And they were licensed for the use of limited number of concurrent users. When the concurrent number of users reached the limit for a software package then new users couldn't run it at all and were notified that all of the licenses have all been taken up and retry later. Now here is the problem: How can you implement such a license mechanism so that no change to either in software package or client machines would be necessary. Design and implement your solution using proxy design pattern. Implement your own error mechanism to represent the case where no license is available.
• In the textbook read "7.15. A Few Words of Advice" and discuss it.
• Create a sample program that simulates a race condition. So it should run fine when run sequentially but cause trouble when run in two or more goroutines.