As you want to get the details of between MCS and M.Sc (Computer Science) so here is the information of the same for you:

MCS is a non thesis degree. The MS is awarded with or without a thesis, and is usually awarded only to student’s enroute to the PhD.

For MCS entrance exam is held and a criterion is that you must have mathematics in 12th standard. The exam covers various areas like
Probability, Calculus, etc. Also Computer organisation and language
questions are also asked.