The 64-bit operating system is one that is capable of storing information in memory that is at least 64 bits or 8 bytes wide. They are also based on registers, address buses, or data buses of that same size. A bus is a subsystem that transfers data or power between computer components inside a computer or between computers. The bus is controlled by a device driver similar to those that control outside peripherals like a mouse or printer.
64-bit CPUs have existed in super computers since the 1960’s and work stations and servers since the 1990’s. While this architecture has been around for awhile, 64-bit operating systems are relatively new concepts in the computer world. Windows XP, Windows Vista, and Mac OS X Tiger are all 64-bit operating systems.
The advantages to 64-bit operating systems are far-reaching. They are more powerful and more reliable than the 32-bit systems. The 64-bit operating system can address more memory directly without using complex indexing or register-addressing schemes. Because internal memory is several orders of magnitude faster than storage, combining a 64-bit processing architecture with more RAM lets a processor pull more data into memory and operate on it directly, increasing performance manifold.
A 64-bit file system also can improve disk management. Rather than having to take a large disk, such as a 9 GB storage module, and segmenting it into 32-bit addressable chunks (2 GB each), you can address the entire disk. That can help, for example, both in database performance and the performance of the operating system itself.
