How does it work?:
What are 'Microprocessors'?
Microprocessors are used in a very wide variety of devices, such as automobiles to industrial control systems.
How do Microprocessors work?
- The date is the year that the processor was first introduced. Many processors are re-introduced at higher clock speeds for many years after the original release date.
- Transistors is the number of transistors on the chip. You can see that the number of transistors on a single chip has risen steadily over the years.
- Microns is the width, in microns, of the smallest wire on the chip. For comparison, a human hair is 100 microns thick. As the feature size on the chip goes down, the number of transistors rises.
- Clock speed is the maximum rate that the chip can be clocked at. Clock speed will make more sense in the next section.
- Data Width is the width of the ALU. An 8-bit ALU can add/subtract/multiply/etc. two 8-bit numbers, while a 32-bit ALU can manipulate 32-bit numbers. An 8-bit ALU would have to execute four instructions to add two 32-bit numbers, while a 32-bit ALU can do it in one instruction. In many cases, the external data bus is the same width as the ALU, but not always. The 8088 had a 16-bit ALU and an 8-bit bus, while the modern Pentiums fetch data 64 bits at a time for their 32-bit ALUs.
- MIPS stands for "millions of instructions per second" and is a rough measure of the performance of a CPU. Modern CPUs can do so many different things that MIPS ratings lose a lot of their meaning, but you can get a general sense of the relative power of the CPUs from this column.
What's a Chip?
A chip is also called an integrated circuit. Generally it is a small, thin piece of silicone onto which the transistors making up the microprocessor have been etched. A chip might be as large as an inch on a side and can contain tens of millions of transistors. Simpler processors might consist of a few thousand transistors etched onto a chip just a few millimeters square.