0.5 lessons

On some schools, there are some lessons with length half of period. aSc Timetables supports only period lengths 1,2,3..., so it is not possible to input this directly. However, in most cases this can be solved by one of these two solutions:

Solution 1: On many schools, only first period every day has length 0.5 and all 0.5 lessons must go on these periods. In this case, you can handle this situation be defining new Type of subject (Time-off) for 0.5 lesson's subject in the way that it can go only on this first period every day, and Type of subject for all other subjects that it can't go on the first period. With this solution everything will be ok, only you have to take in mind that program will show incorrect total number of lessons for teacher and class. You have to subtract from this 0.5*number of half lessons to get correct number.

Note: This solution may be applied on any type of school, where there are predefined positions for whole lessons and predefined positions for 0.5 lessons and these position do not overlap. E.g. on some school, all afternoon lessons might be 0.5.

Solution 2: Other solution is to double length of all lessons in timetable. So you will input lessons with length 0.5 as 1, with length 1 as length 2, with length 1.5 as length 3, with length 2 as length 4, etc. You will have also to adjust Bells and Time-offs accordingly.
How can I define Double/Triple etc lessons?

Solution 3:If 0.5 lessons per week means that you have 1 period every second week, then you need to use weekly timetables:
How can I define weeks?