Consider a demand paging memory management system with 32-bit logical address, 20-bit physical address, and page size of 2048 bytes. Assuming that the memory is byte addressable, what is the maximum number of entries in the page table? 

A.

221

B.

220

C.

222

D.

224

Solution:

LA = 32 bits
PA = 20 bits
PS = FS = 2048 Bytes = 211 bytes 
We know that
      ┌── P (21)
LA (32)
      └── d (11)
∴ With 21-bit page number, the number of pages
in process = the number of entries in PT = 221