1. Paging Examples
Assume a page size of 1K and a 15-bit logical address space.
How many pages are in the system?

2. Paging Examples
Assume a page size of 1K and a 15-bit logical address space.
How many pages are in the system?
How many bits are required to address each byte within a 1024-byte page?

3. Paging Examples
Assume a page size of 1K and a 15-bit logical address space.
How many pages are in the system?
How many bits are required to address each byte within a 1024-byte page? 10 (2^10 = 1024).
This leaves 5 bits for page number.
So, How many pages are in the system?

4. Paging Examples
Assume a page size of 1K and a 15-bit logical address space.
How many pages are in the system?
How many bits are required to address each byte within a byte page? 10 (2^10 = 1024).
This leaves 5 bits for page number.
So, How many pages are in the system?
32 (2^5 = 32)

5. Now consider a 15-bit address space with 8 logical pages
Now consider a 15-bit address space with 8 logical pages. How large are the pages?

6. Assuming a 15-bit address space with 8 logical pages
Assuming a 15-bit address space with 8 logical pages. How large are the pages?
Answer: 2^12 = 4K. It takes 3 bits to reference 8 logical pages (2^3 = 8). This leaves 12 bits for the page size and thus pages are 2^12.

7. Assume a 15-bit address space with a page size of 1K.
Consider logical address 2049 and the following page table for some process P0.
Assume a 15-bit address space with a page size of 1K.
What is the physical address to which logical address 2049 will be mapped? 8 3

8. Assume a 15-bit address space with a page size of 1K.
Consider logical address 2049 and the following page table for some process P0.
Assume a 15-bit address space with a page size of 1K.
What is the physical address to which logical address 2049 will be mapped?
Logical Pages
Step 1. Convert logical address to binary:
Logical address: 1 2 3 4 8 3

9. Step2. Determine the logical page number:
Logical Pages
Step2. Determine the logical page number:
Since there are 5-bits allocated to the logical page, the address is broken up as follows:
Logical page number offset within page 1 2 3 4 8 3

10. 8 3
00010
00011
Step 3. Use logical page number as an index into the page table to get physical page number.
Logical Address:

11. 8 3
00010
Step 4. Concatenate offset with physical page frame number
Logical Address

12. 1 2 3 4 8 3
P0.1
1024
2048
P0.2
4096
= 3073