Understanding "Core"

The word "core" gets a great deal of use (and abuse) these days. The rise of microprocessors with increasingly large numbers of cores brought the word into the computing mainstream, and Intel's usage of the word as part of its name for new processor designs has only muddied the waters.

So let us unmuddy them. This page will cover the guts of all the various computer-related uses of the term "core", and hopefully dispel a good deal of the associated confusion.

History

Once upon a time in the Iron Age, a "core" was a memory storage device. Core in that time refered to memory based on ferrite cores. The cores were wrapped with wires, which could magnetize them in one of two polarities. Those polarities were used to represent single bits of data: a 1 or 0. If this sounds to you like it would be slow, complicated, and costly, then you've got a pretty good grasp of it.

This technology was (fortunately) replaced by various classes of EEPROM, which are faster, cheaper (eventually), and smaller. However, this usage still survives in language. The phrase core dump originally refered to a full copy of whatever was being stored in core memory, and has survived in related usage.

General use

As this memory technology became increasingly obsolete and increasingly forgotten, the notion of "core" refering to a memory type began to fade. And so a new meaning came to predominate. People increasingly refered to processing cores; that is, the component of a computer processor (or embedded processor, or what have you) that executes instructions and crunches numbers. This meaning is now very broadly accepted and quite commonly used. And this meaning is the genesis of the different uses of the word that we will examine below.

Single core/Dual core/Multi core

Also sometimes hyphenated (single-core, dual-core, etc.), these phrases are used to indicate the number of processing cores contained in a particular processor. As might be expected, a single-core processor has one core, a dual-core processor has two, a quad-core processor has four, and so on. "Multi-core" simply indicates a processor has more than 1 core.

These designations are not specific to any one company or brand. They are generic descriptors of a processor feature. A fairly good analogy would be to cylinders in a car engine: both Ford and Chevy make vehicles with 6-cylinder engines, and a very diverse set of vehicles contain 6 cyliner-engines.

Increasingly, the phrase "duo core" is used in place of "dual core". This is the byproduct of confusion between the notion of a dual core processor in general and Intel's Core Duo (below), a processor that happens to be dual core. "Solo core" has similarly begun to see some use.

Intel Core

In 2006, Intel released a line of notebook processors that were essentially an evolution of the Pentium M notebook processors. These took two forms: Core Solo and Core Duo. Both were at their heart an update to the Pentium M; the difference being, Core Solo has one core and the Core Duo has two.

It was at this point that confusion over the word "core" and its application began to develop. Mutations of the product names ("Duo Core", "Solo Core") only worsened the trouble.

Intel Core 2

Later in 2006, Intel released the first of its Core 2 product line. Core 2 products are based on the Intel Core microarchitecture (below). The first products launched were the Core 2 Duo (dual-core) and Core 2 Extreme (dual-core at launch, later versions to be quad-core). The Core 2 Quad (quad-core) and possibly Core 2 Solo (single-core) are to follow. It is important to note that not all Core 2 processors are dual-core.

Core 2 processors come in both desktop and laptop flavors, unlike the laptop-only Core Solo and Core Duo.

Intel Core microarchitecture

Originally dubbed Intel Next Generation Micro-Architecture (NGMA), the Intel Core microarchitecture is a new microarchitecture that combines the strength of Intel's P6 and Netburst microarchitectures. What's a microarchitecutre? Roughly, it's a particular way to implement the guts of a processor. The overall structure and flow of how it works.

All Core 2 processors (Duo, Quad, Extreme, etc.) are based on Intel Core. Additionally, some Xeons are based on Intel Core. There is some possibility that future products based on Intel Core will be launch under the Pentium or Celeron brands.

The future

Intel has indicated that its future desktop and notebook processors will continue to use variants on the Core name. The generation after Core 2 would then be Core 3, and then Core 4, and so on. These generations are meant to correspond to changes in microarchitecture, which are to be more frequent in the future.

There is some uncertainty about what the corresponding microarchitectures will be called; currently "NGMA2" and "NGMA3" are the official names for the next two generations.

Conclusion

The proliferation of meanings for "core" can rapidly become very confusing. And it promises to just get worse. While there is no real way to fight the overloading of this term, learning the ropes of its various uses is not extremely demanding. And from the look of things, it will be valuable knowledge to have for a good long while.

Footnote, Sept. 4, 2007: Intel is now being sued by a company called DualCor for its use of the term "dual core". Go figure.

Born: October 28, 2006; Cleaned: June 28, 2008
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