Windows 7 Can anyone help me with a question on page filing and RAM for university pls? Thanks!

[deucalion0]

Hi there all, this is my first post and I an new to this kind of forum! I am kind of forced to ask for help as I have no way of finding my answer through using Google, as this seems a bit complicated.

Basically my lecturer asked me 5 questions, 3 I think I figured out the other two I need clues as to how to find and learn the information needed I was hoping some clevr helpful person around here might be kind enough to give me a couple of pointers!

The questions I am stuck on are:

4. Paging in a virtual memory system allows nearly all contents of RAM to be paged to and from the hard disc. However, there must be some pages that are never swapped to disk. List one example, and give reasons.
5. Construct a diagram to show the mapping of a 64-bit virtual address to a physical address of 30 bits with a page size of 64K bytes.

I work hard at university and aim for A's all the way, and sometimes questions just seem difficult to answer.

Thanks anyone who takes the time to help me out I really appreciate it!!

Thanks,

Ray.

 

[ChatGPT]

Hello Ray, I'm here to help you with the questions you're stuck on from your lecturer. Let's break down each question and provide you with the necessary information:

4. Pages Never Swapped to Disk in Virtual Memory Systems:​

In a virtual memory system, paging allows the system to move data between RAM and the hard disk. However, there are certain pages that are essential to the system's operation and should not be swapped out to disk. One example of such pages includes:

• Kernel Pages: Pages that belong to the operating system's kernel should never be swapped to disk. This is because the kernel is crucial for the system's functioning, and moving it to disk would significantly degrade performance or even crash the system. Kernel pages contain critical code and data structures that need to remain in physical memory to maintain system stability.

  5. Mapping a 64-bit Virtual Address to a 30-bit Physical Address:​

  To construct a diagram showing the mapping of a 64-bit virtual address to a 30-bit physical address with a page size of 64K bytes, you can follow these steps:
  1. Calculate Parameters:
     • Virtual Address (64 bits): ( 2^{64} ) possible addresses.
     • Physical Address Bits (30 bits): ( 2^{30} ) possible addresses.
     • Page Size (64K bytes): Each page contains ( 2^{16} ) bytes.
     []Determine Components:
     • Page Offset: Calculate the number of bits needed for the page offset.
     • Virtual Page Number: Determine the number of bits for the virtual page number.
     • Physical Frame Number: Calculate the bits required for the physical frame number.
     []Create the Diagram:
     • Visualize how the bits are divided in the virtual address (64 bits) for page offset, virtual page number, and how they map to the physical address (30 bits). Would you like to see a detailed calculation and diagram illustrating this mapping? Let me know if you need further assistance or clarification on any of these steps!