Today’s PCs come in two varieties: those running a 32-bit operating system
and those running a 64-bit operating system. The difference is the
amount of information the PC’s processor can handle at any precise
moment. While a computer designed for a 64-bit operating system has
vastly more potential computing power, it requires fundamental changes
to the way its software is designed.
The word "bit" refers to the way computers deal with information in binary,
where all data is listed as a string of digits which can either be a 0
or a 1. Each of these digits is known as one bit, meaning a 32-bit
processor can process 32 digits at once. Don’t confuse this with memory,
which measures the total amount of information a computer can remember
without needing to use a storage device such as a disk. While the figure
for memory will be much bigger, a computer can’t process all of that
information at once.
The software for a computer with a 32-bit
processor, including operating systems such as Windows, has to be
specifically written to match that processor. The same applies to 64-bit
processors. Microsoft produced 32-bit and 64-bit editions of Windows XP
and Vista, and will do the same for Windows 7.
There are also some significant mathematical limits to the two
different types of processor. A 32-bit processor can only work with a
maximum of 4GB of memory, and this is usually limited to 2GB for any one
program. A 64-bit processor could theoretically work with 17 billion GB
of memory. A 64-bit processor can also carry out some tasks twice as
quickly.
The memory limitations of a 32-bit processor started to become clear
with Vista, which uses a large amount of memory and can make it
difficult to run multiple programs at once without using up even a full
4GB of memory. Meanwhile, it once seemed impossible that any one program
would need more than 2GB of memory, but some modern video games have
hit that limit. For these reasons, 64-bit processors will likely start
to become much more popular, which will increase the number of consumers
interested in buying a 64-bit operating system.
The 64-bit editions of Windows can run some software designed for the
32-bit edition through a special compatibility mode, but the results
can be very varied. Using a 64-bit operating system can also cause
problems with drivers. These are small pieces of software that
coordinate each hardware device with an operating system such as
Windows.
Photo courtesy from: http://lirent.net/2008/04/free-operating-system-icons-pack/
