title: OPERATING SYSTEMS: what is the size of the virtual memory?
body: <p>LINK 1: <a href="https://stackoverflow.com/questions/11809294/if-size-of-the-physical-memory-is-232-1-then-what-is-the-size-of-virtual-memorK">If size of the physical memory is 2^32-1, then what is the size of virtual memory?</a></p>
  
  <p>the above link gives me an answer but i still do have some doubts.
  pls answer in the way the questions posted here so that i will not be confused.....</p>
  
  <pre><code>1.Virtual memory is also called as Demand Paging whenever a page fault occurs 
    the operating system swaps the required page from the virtual memory. the virtual memory
    here mean the harddisk or secondary storage. So how much space can be allocated for a
    porcess in virutal memory? can this size(the space allocated for each process in the 
    Virtual memory) exceeds the size of our RAM size? i mean if our RAM is 4GB then what is 
    the maximum size of the virtual memory you can have for a process?can we have 4GB of 
    virtual memory for every process or can we have more than 4GB for every process?
     (if it needs)
  
  
  2.is the Virtual memory size fixed or dynamic? How much space is allocated for this memory
    and in the above link it is told that 2^48 is the size of virtual memory in 64 bit machine
    why is it only 2^48 and how can once can say a number like that? 
  </code></pre>
  
  <p>thank you </p>