Your total grades are calculated by considering minors and major exams . There are three minors and best of two is considered while at the end of semester you have a major exam. Normally Saturday and Sunday is holiday and you've a month vacations after the completion of the semester .
There are two types of exams- minor (sessionals) and major(finals). Majors are in April-May for even semester and in Nov for odd semesters.
Minors can be taken whenever the teachers want. There is no fixed time or datesheet for that. Usually minors are after one month of beginning of semester.
Semester exam is in April and November.Summer holiday is of two and half months which start from May to Mid July and Winter holiday is of 1 month which is in December.