If I don't active the page mechanism

Hi all: I have a problem, if i don't active the page mechanism just use the segment mechanism at the x86 cpu, how can I manage the Multi-tasking? My view is to use the different base and limit in segment mechanism to divides different task, but this way will cause another problem that is the task which will run must have know which way another tasks line in the memery, if not ,this task may have Conflict with other tasks. If it is true, who can tell the infomation to the task? and if not, how to manage the Muit-tasking just use the segment mechanism? thanks Fan