Prime numbers (in Ruby)

For me it is like back to the basics. Back to the roots. Eratosthenes sieve. I remember when I implemented this algorithm for the first time. It was in a high school and I was feeling like doing a rocket science. Today I would like to look at the algorithm once again but from Ruby perspective.

Java synchronizers - Semaphore

It has been a while since I wrote post about CountDownLatch. Over two months actually but it doesn’t mean I forget that I promised to write about the other synchronizers. So to not speak idly today I'm going to write about Semaphore class.