Contents
What is page number in operating system?
Page number(p): Number of bits required to represent the pages in Logical Address Space or Page number. Page offset(d): Number of bits required to represent particular word in a page or page size of Logical Address Space or word number of a page or page offset.
How do you find the number of physical pages?
In your example, page size is 16 KBytes, so log2(16*2^10) is 14; that is, page offset is 14 bits. Then, calculate Physical Page Number (PPN) size by subtracting page offset from total number of bits allocated for physical address. Since in your example, physical address is 32-bit, PPN = 32 – 14, or 18 bits.
How do you calculate the number of pages in a virtual address space?
The total memory of millions of bytes is actually organized in chunks called pages. Here total memory of 2^32 bytes is chunked into pages of 2^12 bytes. what is the number of pages? the answer is (2^32)/(2^12) = 2^20.
What is page frame number?
A block of RAM, typically 4KB in size, used for virtual memory. A page frame is a physical entity with its own page frame number (PFN), whereas a “page” is content that floats between memory page frames and storage (disk or SSD).
How do I find the page number and offset?
- page number = A / page_size. this is the page number within the process address space. e.g. address in the process, A = 10,000. page size = 4k.
- offset = A mod page_size. this is the distance from the beginning of the page. e.g. address in the process, A = 10,000. page size = 4k.
How do I find the page size in a table?
Consider a system with a 32-bit logical address space. If the page size in such a system is 4 KB (2^12), then a page table may consist of up to 1 million entries (2^32/2^12). Assuming that each entry consists of 4 bytes, each process may need up to 4 MB of physical address space for the page table alone.
How many bits long is a physical page number?
How big is the page table? From the previous slide: — Virtual page number is 20 bits. — Physical page number is 18 bits + valid bit -> round up to 32 bits.
How do I calculate page numbers with offset?
What is the total number of entries in the page directory?
1024
A page directory comprises 1024 32-bit entries. The Page Directory Entry (PDE) is selected using the high-order address bits (31-22) from the linear address along with a base address provided by CR3.
How do I find the page table entry?
Consider a system with a 32-bit logical address space. If the page size in such a system is 4 KB (2^12), then a page table may consist of up to 1 million entries (2^32/2^12).