System on module

Unlike a single-board computer, a SoM serves a special function like a system on a chip (SoC).

The devices integrated in the SoM typically requires a high level of interconnection for reasons such as speed, timing, bus width, etc.

There are benefits in building a SoM, as for SoC; one notable result is to reduce the cost of the base board or the main PCB.

In the mid 1980s, when VMEbus blades used M-Modules,[1] these were commonly referred to as system On a module (SoM).

SoMs were used extensively by Sun Microsystems, Motorola, Xerox, DEC, and IBM in their blade computers.