This here past exam paper talks about 'fixed size partitions'. What's one of them? Did I miss a lecture?
'Fixed size partitions' are a very primitive memory management approach.
The memory partitioning approach discussed in the lectures assumed that memory was one big lump which you could carve into bits (using some heap allocation strategy).
By contrast, a system which uses fixed size partitions carves up the available memory before any processes start to run. When a process wants to run, the OS finds a partition of a suitable size, and loads the process into that partition. There are various strategies for choosing an appropriate partition for a process of a given size.
This is, like, ancient history, which is why we didn't cover it in the lectures, and it won't appear in the exam.