Why Use a Passive Backplane?
Why would you use a passive backplane and Single Board Computer? The three primary reasons are more expansion slots, need for ISA slots, and much lower MTTR (Mean Time To Repair). Motherboards are limited to 8 slots maximum – at the most. It’s getting hard to find even that many. Passive Backplanes can provide up to 20 slots. 20 is the most that will fit within a 17″ wide rack mount chassis. You can build a backplane with more than 20 if your chassis is wide enough to accommodate the board. Intel and Microsoft decreed some time ago that ISA slots will no longer be supported. New motherboards only provide PCI slots. If you have an application that is served by a plug-in I/O which is only available in ISA form factor, you are limited to looking for used or old stock motherboards or switching to a passive backplane. A passive backplane can provide up to 20 ISA slots. However, 1 or 2 of those slots would be occupied by the SBC leaving 18 available ISA card slots. An SBC can be removed from
