It's not just tinkerers who suffer. At our university research group we're doing ultra high speed OCT imaging research. Without going into full details, let it just sink in that were're fully saturating two PCI-E x8 Gen3 toward GPU cards in a continuous stream. Since CUDA-5 there's an API that allows direct DMA between the GPU and whatever device you can write drivers for.

This opens an interesting opportunity: Put the ADC and the GPU into an external PCI-E enclosure with a PCI-E crossbar switch (PLX/Avago makes those). Unfortunately there are no existing enclosures that support the number of slots and the PCI-E generation required for that.

But what the heck, we've got all the tools here required to design, and more importantly troubleshoot such a design. I've got a 4ch 35GHz bandwidth Oscilloscope at my disposal here and there's be a >60GHz one at the lab soon, too. Also all the kinds of probes required. And being a radio amateur with interest in microwave operation there's also the technical background. A quick search at Mouser and Digikey reveals, that they even have all the right ICs in stock. So all I need is electrical specifications for what to keep in mind, pin outs, and some programming manuals for the controller.

Now there are two options to go about this: Using External-PCI-E connection (adapters for which for some reason have become hard to come in the past 2 years) or Thunderbolt. So I thought, hmm, it's worth a try getting in touch with them (heck, some guy at HN actually suggestest I should get in touch with the Thunderbolt groups). Here's the reply in verbatim:

> Dear Wolfgang,
>
> Thank you for your interest in Thunderbolt™ technology. Due to resource
> constraints we are not able to approve Individuals or institutions to sign
> the Thunderbolt Technology License that is required for access to Thunderbolt
> Confidential documentation. As our resources improve we hope to be able to
> allow individuals or educational access.
>
> You may find the attached Intel Developer Forum presentation from August 2015 helpful.
>
> If there is a specific Thunderbolt product you are trying to bring to market please let us know.
>
> Thank you and best regards,
> Thunderbolt Admin

Yeah, thank you very much.

It always puzzles me why hardware companies, who want to _sell_ their stuff or proliferate their newest kind of technology makes it so awfully hard for independent developers, engineers, researchers and tinkerers to actually make use of it in their products.

As far as I can tell there's not really much on the Thunderbolt market available right now. A few storage enclosures, NICs, single slot PCI-E enclosures and the occassional novelty audio interface. You can, in fact, enumerate all existing products that use Thunderbolt technology on the Thunderbolt website itself.

In a broader sense the same problems also hold for PCI-E and PCI (fortunately the specifications for those float around the web, you can find them if you want to) and "standard" links like DisplayPort and HDMI.

And apart from the whole hardware building aspect, there's also the software aspect. Hey you various printer and scanner manufactureres out there (I'm looking at you EPSON, Canon, Samsung, Brother, Kyocera, etc.) you want me to buy your stuff. So how about you also tell me how to talk to it, once I've bought it. You know, drivers are not really terribly complicated things. Yes I understand you may have some secrets in your drivers. I don't want to get the sources to _your_ drivers, I want to write my own. Oh I could damage my hardware you say? What problem is that for you, you should be happy, I might buy another pice from you. I think it has to do with the fact, that you're selling the very same piece of hardware in different feature editions for different prices and you don't want to tell people that plainly.

/rant