answer to second one
with out operating system it wud be graet difficulty bcoz

1.if we want to perform atask we should interact with hardware through machine language

2. we shud have grip over how they work
3.it wud be difficult to find errors if they occur during a execution
4. we ourselves shud manage the memory
we ourselves shud take care of device assignment to process

and many more tasks to take care by user inorder to work on computer without os

even though we have expert systems with gud perforamnce
without os their through put degrades to worst level

In computer science, memory virtualization decouples volatile random access memory (RAM) resources from individual systems in the data center, and then aggregates those resources into a virtualized memory pool available to any computer in the cluster.[citation needed] The memory pool is accessed by the A or applications running on top of the operating system. The distributed memory pool can then be utilized as a high-speed cache, a messaging layer, or a large, shared memory resource for a CPU or a GPU application.

if the program size is more than the primary memory of our system, then virtual memory architecture is used,by keeping only the part of the program which is currently in use in d main memory and rest of the program in disk, we can run d programs whose size is more than the system memory size. one of the popular virtual memory management technique is paging.

if the program size is more than the primary memory of our system, then virtual memory architecture is used,by keeping only the part of the program which is currently in use in d main memory and rest of the program in disk, we can run d programs whose size is more than the system memory size. one of the popular virtual memory management technique is paging.

if the program size is more than the primary memory of our system, then virtual memory architecture is used,by keeping only the part of the program which is currently in use in d main memory and rest of the program in disk, we can run d programs whose size is more than the system memory size. one of the popular virtual memory management technique is paging.

virtual memory
It is a part of secondary memory that act as a back up for main memory.A memory that virtually present.Usually program should be present in the main memory for execution.since multiprogramming is supported by modern system,main memory doesn't have enough space to hold all these programs.so certain pages of all programs are kept in the main memory in the slots allotted for that process and rest is kept in the secondary memory.As program need additional pages it get swapped in to the main memory.This technique is called as swapping.

If you have the better answer, then send it to us. We will display your answer after the approval.
Rules to Post Answers in CoolInterview.com:-

There should not be any Spelling Mistakes.

There should not be any Gramatical Errors.

Answers must not contain any bad words.

Answers should not be the repeat of same answer, already approved.

Answer should be complete in itself.

Name :*
Email Id :*
Answer :*
Verification Code	Not readable? Load New Code
Enter the above shown code:*
	Inform me about updated answers to this question