U.2 over SFF-8644?

[chx]

So the U.2 connector is per Making Sense of Next-Gen SSDs this article is a "slightly modified" SFF-8643. I can't find a description of this "slight modification". Would SFF-8643 to SFF-8644 adapters work? In other words, is it possible to run PCI Express x4 via an PCIe-U.2 adapter followed by a SFF-8644 to SFF-8643 adapter and the other end another SFF-8644 to SFF-8643 adapter and then a U.2 to PCIe x4 slot? All of these adapters exist I am just wondering whether it would work.

 

[amarton]

So the U.2 connector is per Making Sense of Next-Gen SSDs this article is a "slightly modified" SFF-8643. I can't find a description of this "slight modification". Would SFF-8643 to SFF-8644 adapters work? In other words, is it possible to run PCI Express x4 via an PCIe-U.2 adapter followed by a SFF-8644 to SFF-8643 adapter and the other end another SFF-8644 to SFF-8643 adapter and then a U.2 to PCIe x4 slot? All of these adapters exist I am just wondering whether it would work.

It might. I don't know if the latency and signal strength loss added by the cable can be an issue - SAS accounts for these, PCIe probably doesn't. Do you have any particular application in mind?

 

[chx]

Two part chassis for easier transportation.

 

[amarton]

They have those; I can't post links but google "pcie expander chassis". They come with a host card, an expansion card in the chassis, and usually two SAS-like cables for connectivity. It's pretty expensive though.

I don't think what you describe above would work for more than a single card.

 

[lutjens]

As far as I know, the U.2 version of the cable has the requisite shielding to protect the integrity of the data and the integrity of treference clock (which must be present unless using a SRIS device).