When you sit at your computer, browsing the Internet, playing video games and running word processors, it's easy to feel like you're in control. But have you ever thought about what really makes your desktop or laptop run?
The central processing unit (CPU), or the microprocessor, is the heart of your desktop of laptop computer, a tiny chip that contains an entire computation engine on top.
The first commercial microprocessor, the Intel 4004, was introduced in 1971. Although it couldn't do much -- it could only add and subtract four bits at a time -- it powered one of the first portable calculators.
Computer chips are small pieces of silicon onto which transistors are etched. Much of the microprocessor-producing industry is located in the San Francisco Bay Area in Southern California and has earned the nickname of "Silicon Valley."
The smallest wire on a chip is measured in microns. Current chips have wires that are less than one micron wide, while a human hair is about 100 microns thick.
Although CPUs have many complicated tasks to run, they do three basic things: perform mathematical operations, move data between memory locations and follow sets of instructions. The job of starting up the computer specifically involves the bootstrap loader.
Address and data buses, which send addresses and data to memory, and read and write lines, which tell the memory whether it wants to set or get an addressed location, can connect to either ROM or RAM and generally connects to both.
ROM stands for read-only memory. Unlike RAM (random access memory), ROM chips are programmed with a set of bytes that can't change.
When the microprocessor starts up, it looks towards the BIOS for several instructions. Among other things such as storing the boot sector in RAM after it's read, BIOS instructions check the machine's hardware for errors and then load the operating system.
Because humans aren't very good at remembering complex bit patterns, the assembler translates semantic instructions developed by designers into a language the CPU can use.
While 32-bit microprocessors can only address between 2 and 4 gigabytes of RAM, 64-bit microprocessors can address as much as one billion gigabytes of RAM if needed. Although that may seem excessive for something like home computers, such extra space may be necessary in the future for overloaded servers.
The 8086 popularized 16-bit technology, which helped make it the first of an influential series of CPU chips.
The i7 packs 731 million transistors onto its CPU chip. Count 'em.
The motherboard holds the CPU, memory cards and various ports and controllers.
The clock speed indicates how quickly the CPU can execute instructions. The frequency is measured in megahertz or gigahertz.
However instantanous the actions of a computer seem to be sometimes, every little operation takes time. Retrieving data from the cache, however, is much faster than retreiving from system memory.
Process size refers to how finely the CPU components are etched on to the chip. In 2012, the process size for chips had reached 22 nanometers.
Turbo boost increases the power and speed of a CPU when more processing power is needed.
Getting rid of heat is important to keeping a CPU running. Passive heat sinks or fans are the most common methods.
The original PC, introduced in 1981, used an 16-bit processor, but it only had an 8-bit bus to carry the data.
Intel Corp. created its 4004 programmable chip for calculators in 1971.
Along with Intel, Advanced Micro Devices, known as AMD, is a major maker of microprocessors.
More of an estimate that has held somewhat true than a law, the idea was first put forth in 1965 by Gordon E. Moore, co-founder of Intel, who at first predicted the number would double every year. The term is still used in computing circles, but the time frame gets revised periodically.
Many of today's CPUs include multiple processing cores, allowing the divvying up of instructions to speed up processing. It should be noted that two cores don't double speed, as there are other factors at play.
Most new computers have CPUs with multiple processing cores integrated into one chip to increase speed and efficiency, often as many as four. But chip makers are working on massive multi-core processors, also called many-core processors, with dozens or even hundreds processing cores to handle even heavier processing.
A processor contains many millions of transistors etched right into the silicon. Electrical signals are applied to make the transistor either allow or disallow the flow of electricity.
Many of our smaller computing devices, such as smartphones and smart watches, use system-on-a-chip (SoC) processors to pack a ton of computing capability into a tiny package. These chips may include the CPU, GPU, RAM, ROM and other components all on one integrated circuit.
Many everyday devices like dishwashers, cameras, thermostats and cars now include processors, albeit smaller and less powerful ones than those in most computers. Non-computer devices containing processors are often referred to as embedded devices.
The arithmetic logic unit (ALU) performs arithmetic operations like addition, subtraction, multiplication and division and logic operations such as AND, OR, NOT, NAND, NOR and XOR.
As opposed to CISC (Complex Instruction Set Computer) architecture, in which the hardware has a large set of more complex instructions, RISC (Reduced Instruction Set Computer) architecture includes a more optimized set of simple instructions, each requiring fewer transistors and executing in only one clock cycle. These instructions can be strung together via software to perform more complex operations.
The semiconductive material silicon is used to make most microchips because changes in conditions (such as current and voltage) can be used to control how conductive of electrons it is at a given moment, allowing controlled flow of electricity.
A CPU's registers can hold data, such as computing instructions or storage addresses, for use in processing.
Integrated circuits were conceived of in the late 1950s when engineers realized you could make computing components smaller by etching transistors, resistors and capacitors into a solid block of silicon rather than stringing them together with wires. And thus the modern microchip was born.
The program counter is a type of register that contains the address of either the current or next instruction to be executed.
The company Advanced RISC Machines (ARM) developed processors using RISC architecture that allowed for small chips with high-speed performance at low-power, making them ideal for small devices like smartphones, tablets and wearable devices.
Die size is a term used to refer to the surface area of the microchip, usually in square millimeters.
However instantaneously your computer seems to react, every little action takes time. Retrieving data from the cache, however, is several times faster than retrieving from RAM (random access memory). Both are usually measured in nanoseconds. One nanosecond is a billionth of a second.