Question

a system with virtual memory has a page size of 256 bytes and uses 16-bit virtual memory addresses. the physical memory of the system has a capacity of 16 pages. the following table shows a part of the page table for a program running on this system. valid bit values are given in binary. vpn and ppn values are given in hexadecimal. vpnvalid bitppn011105217318412516the system has a four-entry, fully-associative tlb that looks like this:validtagphysical page number1421271560xx flag question: question 1question 10.2 ptshow many bits does the system use for the virtual page number?

Answer 1

The system uses 8 bits for the virtual page number to uniquely address the 2^8 different pages in a 16-bit virtual memory address space with a page size of 256 bytes.

Step-by-step explanation:

To determine how many bits are used for the virtual page number (VPN) in a virtual memory system with 16-bit virtual memory addresses and a page size of 256 bytes, we first need to calculate the number of pages that the virtual memory can address. The size of the virtual memory address space is given by the number of bits in the virtual address, which in this case is 16 bits. Since the page size is 256 bytes, we can calculate the total number of virtual pages by dividing the total addressable memory (which is 216 given the 16-bit addresses) by the page size (256 bytes).

Total number of virtual pages = 216 / 256 = 28 (since 256 is 28 bytes).

Therefore, the VPN, which identifies each of these pages, must be 8 bits since it needs to uniquely address 28 different pages.