It is now few years that my mind has been fascinated about the opportunities that the PCI Express specification provides at the system architecture level. My recent tests with a simple, one lane PCI Express extension kit using a 50 meter fiber confirmed that my vision is quickly coming reality.
First, two very simple rules about the COTS systems:
- All industrial COTS cards that got a CPU on them get insufficient to turn a commercial Operating System (OS) within a three years time span
- Industrial I/O cards can live much longer: ten year is not an exception!
Today, the bus has dematerialized and it has become a software protocol that we transfer encapsulated in a transmission protocol on a serialized media, which can be cable, fiber or wireless. So why not finally make a modular system where the slow and fast I/O problems are each separated in to their own entities and the ever changing CPU/OS in its own? Presented with a block diagram, we would get something like this:
The high end solution (fast disks, PCI-Express detector cards, and so on) would look equally modular:
There are some industrial grade 1U height rackable servers around. The following link is not the only one that I found, but the product comes with PCI Express x8 riser card:
http://www.stealthcomputer.com/industrial_rackmounts_sr1501datasheet.htm.
An example of a bus extension system could be the following product:
http://www.amplicon.co.uk/IPC/product/PCI-Rackmount-MAGMA-2906.cfm.
Where’s the beef ?
Wouldn’t the proposed system be more expensive? Sure, for a single purchase. But seeing the annoying fact that the CPUs and Operating Systems are aging much more rapidly than the I/O systems the Total Cost of Ownership (TCO) would be equal or less in the timespan of ten to fifteen years. Only the unit containing the CPU and the operating system needs to be changed while the PCI/PCIe extension unit will not be touched. The immediate saving in money is not substantial but what a relief for the maintenance and software upgrades!
