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Calculates Page size:

Sometimes question may ask to calculate page size where Logical Address (LA) and Page Table Entry (PTE) is given.

Let consider a question:

In a system with 35 bit virtual address and page table entry size is 8 byte, use of single-level page table. Calculate the page size.

Solution:

Here, Virtual Address = Logical Address = 35 bit, so, Virtual Address Space (VAS) = Logical Address Space (LAS) = ${\mathbf{2}}^{\mathbf{35}}$ = 32GB and Page Table Entry (PTE) = 8B = ${\mathbf{2}}^{\mathbf{3}}$

Let Page Size = p.

Now, we know Page Table Size (PTS) 

As we know frame size is always the same as page size i.e. page size = frame size.

Now, in a single level paging system page size or frame size must be greater than or equal to page table size in the system, otherwise, we cannot load this page table into a single frame of main memory.

Another Example:

Question:

Consider a system that has a 1TB process as well as page table entry size 4 byte. The page size of the process is greater or equal to

(A) 8 MB          (B) 4MB       (C)  2MB          (D)  519KB

Solution:

Here, Process size = Virtual Address Space (VAS) = Logical Address Space (LAS) = ${\mathbf{2}}^{\mathbf{40}}$ = 1TB and Page Table Entry (PTE) = 4B = ${\mathbf{2}}^{\mathbf{2}}$

Let Page Size = p.

Now, we know Page Table Size (PTS) 

As we know frame size is always the same as page size i.e. page size = frame size.

Now, in a single level paging system page size or frame size must be greater than or equal to page table size in the system, otherwise, we cannot load this page table into a single frame of main memory.

So, option (C) is correct.