The SFF-SIG is known for standards such as SUMIT (see Playing The Board Game: Stack' em, Pack 'em, And Rack 'em) used in stacking architectures. Its latest offering is RS-DIMM (Fig. 1), a rugged, DDR3 mezzanine module. The module uses a 240-pin Samtec BTH/BSH connector pair that carries signals that mirror the standard DDR3 DIMM. The big difference is that the RS-DIMM module is bolted down providing excellent shock and vibration support. It provides a removable platform much like the FeaturePak (see Module Packs I/O Features) peripheral module.
The RS-DIMM module is 38mm by 67.5mm, slightly larger than an SODIMM module. It has room for 9- or 18-chips with a capacity up. ECC support is optional. So is SATA-2 support. This allows the module to support memory, SSDs or both.
Single board computers (SBC) will likely host a single RS-DIMM socket although multiple sockets are possible. In the past, rugged applications tended to have only soldered memory fixing the amount available to designers. Using standard DIMM sockets was usually not an option. RS-RIMM changes the dynamics providing a more flexible design option. Swissbit and Virtium Technology are showing RS-DIMM implementations.