Computer module

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This article is about computer hardware modules. For computer software and hardware modules, see Module (computing).
DEC's original products were individual modules, like these System Building Blocks 1103 hex-inverter cards (both sides).
Contemporary computer modules look like this Colibri T30 manufactured by Toradex, Switzerland

A computer module is a selection of independent electronic circuits packaged onto a circuit board to provide a basic function within a computer. An example might be an inverter or flip-flop, which would require two or more transistors and a small number of additional supporting devices. Modules would be inserted into a chassis and then wired together to produce a larger logic unit, like an adder.

History[edit]

Modules were the basic building block of most early computer designs, until they started being replaced by integrated circuits in the 1960s, which were essentially an entire module packaged onto a single computer chip. Modules with discrete components continued to be used in specialist roles into the 1970s, notably high-speed designs like the CDC 8600, but advances in chip design led to the disappearance of the discrete-component module in the 1970s.

In the 21st Century, computer modules more commonly refer to computer-on-module used in embedded computing. An extension of the concept of System on Chip (SoC), COM lies between a full-up computer and a microcontroller in nature. Today's Computer On Modules (COM) are complete embedded computers built on a single circuit board. The design is centered on a microprocessor with RAM, input/output controllers and all other features needed to be a functional computer on the one board. However, unlike a single-board computer, the COM will usually lack the standard connectors for any input/output peripherals to be attached directly to the board.

The module will usually need to be mounted on a carrier board (or "baseboard") which breaks the bus out to standard peripheral connectors. Some COMs also include peripheral connectors and/or can be used without a carrier.

A COM solution offers a dense package computer system for use in small or specialized applications requiring low power consumption or small physical size as is needed in embedded systems. As a COM is very compact and highly integrated, even complex CPUs, including multi-core technology, can be realized on a COM.

Using a carrier board is a benefit in many cases, as it can implement special I/O interfaces, memory devices, connectors or form factors. Separating the design of the carrier board and COM makes design concepts more modular, if needed. A carrier tailored to a special application may involve high design overhead by itself. If the actual processor and main I/O controllers are located on a COM, it is much easier, for example, to upgrade a CPU component to the next generation, without having to redesign a very specialized carrier as well. This can save costs and shorten development times. On the other hand, this only works if the board-to-board connection between the COM and its carrier remains compatible between upgrades.

Benefits of Computer Modules[edit]

There are many benefits to using COM products instead of ground-up development. These benefits include increasing speed to market, reduction to risk, cost savings, choice of a variety of CPUs, reduced requirements and time for customer design, and an ability to conduct both hardware and software development at once.