Both unequal fixed size and variable size partitions are inefficient in the use of memory. It has been observed that both schemes lead to memory wastage. Therefore we are not using the memory efficiently.
There is another scheme for use of memory which is known as paging.
In this scheme,
The memory is partitioned into equal fixed size chunks that are relatively small. This chunk of memory is known as frames or page frames.
Each process is also divided into small fixed chunks of same size. The chunks of a program is known as pages.
A page of a program could be assigned to available page frame.
In this scheme, the wastage space in memory for a process is a fraction of a page frame which corresponds to the last page of the program.
At a given point of time some of the frames in memory are in use and some are free. The list of free frame is maintained by the operating system.