What is the difference between 32 & 64 bit operation system?

Its all about the ability of any operating system to hold the maximum size of memory. 

Thirty Two Bit Operating Systems

It can handle maximum 2's power Thirty Two, maximum size of memory (RAM) can be handled by this operating system is Four Gigabyte (GB). 

Sixty Four Bit Operating Systems

It can handle maximum 2's power Sixty Four, maximum size of memory (RAM) can be handled by this operating system is Sixteen Exabyte (EB). 

Note: I have used alphabet to represent the numeric values e.g. Thirty Two, because of the automatic filtering system on Bayt.com is not accepting of any numeric value, I hope you understand.

A computer's CPU (central "processing" unit) capacity to "process" information.-bit has a higher capability than that of the-bit and-bit is not reverse-compatible with previous-bit versions (prior).

If you are an IT person then you must have heard about assembly language. A bit OS contains instruction consist of bits instructions on each memory block while on bit instructions are saved on bit block.If you a non IT person, Then you can consider a narrow path and a wide path, Where a path will allow some instructions to pass and vice versa.

A-bit OS can support memory upto4 Giga-byte, therefore it is mostly used with Desktop PCs.

A-bit OS can support memory upto Exa-byte, therefore it is mostly used with Servers.

However, due to reduction in hardware costs, many desktop and laptop systems are also shipped with more than4 GB Ram, thus required anbit OS.

8 bits =1 byte, one byte mean one charactor i.e. A,b..z, and special characters, so bits mean four characters can be proceed at a time. In other hand-bits mean eight characters can be processed at once so it would be more faster then-bits operation.

for further details please see at http://windows.microsoft.com/en-us/windows/-bit-and--bit-windows#1TC=windows-7

Whether shopping for a new computer or upgrading an old one, you’ve likely come across the the “-bit” designation and wondered what it meant. Read on as we explain what Windows-bit is and why you’d want a piece of that-bit pie.

Windows7 and8 have done an enormous amount to increase the popularity of-bit computing among home users but many people are unclear on what exactly it means (and may not even realize they’re already running it). Today we’re taking a look at the history of-bit and-bit computing, whether or not your computer can handle it, and the benefits and shortcomings of using a-bit Windows environment.

General rule, if you have under4 GB of RAM in your computer, you don’t need a-bit CPU, but if you have4 GB or more.

Software and Driver:

All Software and Driver with high performance already take advantage of the increase in available memory, so it may be used operating system bit

More the bits more fast processing so bit will be more faster and it is double of bit.

The key difference- the terms-bit &bit refer to the way a computer's processor CPU, handles information. the-bit version of windo handles large amount of random access memory  RAM more effective then a-bit system.

these are the process which the processor is used

This is what is referred to as word size. The word size defines the size of data that the processor can access. In other words, the word size dictates the maximum address that the processor can reference in memory.

A-bit processor is limited to2 to the power of memory addresses. Each address holds one byte, mostly. So, if you calculate2 to the power of, the answer would be bytes which is exactly4 gigabyte(binary). You can confirm this yourself by dividing the number by (to convert to KiB) then by (to convert to MiB) and finally by to (convert it to GiB).

A-bit processor can theoretically access exabytes of memory. Though, that is not the case in real life application. A computer would not be able to accommodate so much memory because mainly you do not have room to place all those memory chips.