A microprocessor is a computer processor that consists of only one integrated circuit (sometimes, a minimal number of them clustered together). The single-unit microprocessor has all the logic, control, and arithmetic elements needed to function as a standard PC CPU. An integrated circuit can perform programmed instructions.
Functionally, a microprocessor is the part of a computer known as the CPU. It accepts binary input data, processes it, and then provides output in the form of instructions to the different parts of the computer and some peripherals. Information received is processed by the ALU – the arithmetic logic unit. It is then passed through the control unit and a register array. The register array is a small amount of instantly available memory, critical for high performance. When the data has finished processing, it is passed to the control unit and eventually to whatever other computer elements need.
Microprocessors vs. Microcontrollers
A similar but distinct piece of tech is the microcontroller – although they are made up of much the same things in a parallel configuration, they aren’t used for the same things. Microprocessors are far more powerful in computing power and are thus larger to accommodate the structures needed to support their infrastructure.
Another notable difference is that while a microcontroller has its onboard memory, a microprocessor does not. Memory needs to be connected externally. In most cases, that is in the form of a small amount of RAM and some flash memory. Unlike microcontrollers, microprocessors can run operating systems like Linux or Windows. This makes them more complicated to program – a microcontroller that only executes whatever program is installed directly on it is comparatively easy to set up and get working.
Another pronounced difference is the cost. Microcontrollers are cheap to make and cheap to buy, available for a few dollars apiece. A microprocessor can be one of the most expensive parts of a computer. They can cost hundreds or even thousands of dollars in the case of an AMD Threadripper.
The History of Microprocessors
The first proper microprocessor, the Intel 4004, was invented in 1971. Before that, in 1959, the first integrated circuit was created – a building block required to make the microprocessor possible in the first place. The first generation of microprocessors ended in 1972 – these processors had a clock speed of 740 kHz. It couldn’t do much – even most arithmetic calculations were outside its scope.
The second generation involved the first 8-bit microprocessors – up from 4-bit. This started just six months after the release of the 4004 with the release of the Intel 8008. Though better than the first, the second generation was also almost exclusively useful for control applications rather than as a CPU. While groundbreaking at the time, they were quickly superseded in a rapidly advancing field.
The third and fourth generations were released in the late 70s and early 80s. They were the first that could do more than simple arithmetic. Particularly the fourth generation, the first 32-bit processors, were popular choices for CPUs in computers. This generation includes the first Pentium processor – a famous name in the processor market.
Where the first few generations lasted only a few years, the fifth generation of processors started in 1995 and is still active today. Modern 64-bit processors are overwhelmingly better and faster than older models of the same generation. There is not yet the 6th generation of microprocessors using 128-bit logic. In the currently limited use cases where this word length would be helpful, extensions to the x86 instruction set are available, allowing a 64-bit CPU to operate on 128-, 256-, and even 512-bit data. Doing so comes with an increased power draw and heat output, resulting in a lower clock speed.
A microprocessor is a single-chip, general-purpose processor. Microprocessors are generally found in computers and other computing devices. Some devices, such as mobile devices, may use more complex processors called SoCs or Systems on Chip. These offer extra specialized processing capability on the same single chip as the general-purpose processor. Current microprocessors are 64-bit with no sign of a shift to 128-bit processors.