Overview The central processing unit (CPU) is popularly referred to as the brains of the computer because it is where most of the processing, such as the interpretation and execution of program instructions, occurs. The microprocessor, which is a single chip that carries out all the tasks of a mainframe CPU, can aptly be called a “CPU on a chip,” and the terms CPU, processor, and microprocessor are often used interchangeably.

How does the CPU fulfill its vital role of being the brains of the computer? You can dig deeper into what goes on within the CPU by looking up the Web sites mentioned below.

General Resources You can review the components of the CPU at www.webopedia.com/TERM/C/CPU.html. HowStuffWorks (www.computer.howstuffworks.com/microprocessor2.htm) explains the inner workings of a microprocessor by showing how instructions in a short C language program are compiled, fetched, decoded, and executed. Also discussed within this site are growing trends in microprocessor design, such as 64-bit ALUs.

This Intel Web site (www.intel.com/education/mpworks/intro.htm) features a tutorial that walks you through every step a microprocessor takes when adding two numbers together. Intel is the world’s largest microprocessor manufacturer, with AMD following on its heels. All types of processors, such as the Intel Pentium and the AMD Athlon, are described at www.computerhope.com/jargon/cpu.htm. Aside from processor definitions, ComputerHope.com (www.computerhope.com/help/cpu.htm#01) offers CPU ABCs, details about known CPU bugs, and a history of CPUs, with the Intel 4004 being the world’s first commercial processor.

At this link (www.en.wikipedia.org/wiki/CPU_design), Wikipedia relates some CPU history, with focus on hardware design and architecture. In addition, if you are curious about multi-core processors, that is, microprocessors that combine two or more independent processors in one package, look up http://en.wikipedia.org/wiki/Multi-core_(computing).