CODEWITHSUNDEEP
memory-managementprocessoperating-systemwindows-8.1
NirAv JaIn
NirAv JaIn

Reputation: 1075

Maximum memory that can be allocated to a process on Windows 8.1

I'm a fresher and was asked this question in the Microsoft recruitment process.

I'd read somewhere that the maximum memory allocated to a process can be the maximum physical memory available. So is it that if the RAM is 4GB, that's the answer? If yes, then how? Because some part of the RAM is always occupied by the Operating System, right? If no, then could you tell me the answer and what are the factors it really depends on?

Upvotes: 0

Views: 3170

Answers (1)

Am_I_Helpful
Am_I_Helpful

Reputation: 19158

First of all, the base of your question is totally related to Virtual Memory which has already been pointed out by Chris O!

Now,proceeding to your questions step by step :-

I'd read somewhere that the maximum memory allocated to a process can be the maximum physical memory available. So is it that if the RAM is 4GB, that's the answer?

No, the maximum memory which your process can use can be anything depending on the virtual memory assigned or the swap size. Swap memory is generally taken twice of the physical memory,thought it can always be more or less depending on the requirements!

Also, PAE (Physical Address Extension) allows more memory to be allocated. PAE allows a 32-bit OS to use more RAM, that is, more physical memory. This has nothing whatsoever to do with the 4GB virtual address space limitation that 32-bit OSes have.

A 32-bit OS uses 32-bit virtual addresses. That limits it to 4GB of addressable virtual memory at any one time. If a 32-bit OS also uses 32-bit physical addresses, it is limited to 4GB of physical memory as well. PAE allows a 32-bit OS to use 36-bit physical addresses, which raises the limit to 64GB.

Next, the point which you mentioned is valid for the atomic processes which can't be broken further into threads or So. I doubt one would rarely face that situation in which the size of atomic process is more than that of the physical memory...

If yes, then how?Because some part of the RAM is always occupied by the Operating System, right?

No.it's not as I already have mentioned above!

If no, then could you tell me the answer and what are the factors it really depends on?

The memory requirement of a process is not defined earlier. But, you might have heard about this that many programs recommend at least it must have this much of memory to execute this process. This is the minimal requirement of the process without which the process won't even run properly! Because it must have suitable physical memory to handle those events! Next, the term swapping comes into picture whenever we are talking about Virtual memory! All the process which are currently not running are send to disks and the process which are to be executed are sent to the physical memory for execution.So, more than one processes are requested and executed by continuous swapping!

Some other continuous processes which are maintained in main memory are :-

  1. System processes OR daemons

  2. cache memory or cache maintenance

Upvotes: 3

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