I would expect any end user interaction to be primarily through something like VHDL

I too am wondering about how the FPGA will be accessed from software. I can only assume that there's a built-in DMA interface, and that only one process can grab the FPGA at a time.

Looking at the product brief, it seems that the Intel CPU and the FPGA are being packaged on the same module and connected over PCI-E. So the interface from the processor to the FPGA will be over this connection. I imagine the development flow will be the same as if you connected these devices externally on your PCB. The processor won't need to know its connected to an FPGA, just a PCI-E device, and the same goes for the FPGA. The standard FPGA development flow can be followed.

Why would it need to be accessed from software? There's probably a strong likelihood that hardware manufacturers will configure the FPGA in the factory, and the end-user will end up oblivious to the fact it's even there.

Thats the more likely scenario, but also the much less interesting one, since, at least for me, the possibility of runtime reconfigurable hardware is what makes me like this.

Working with FPGA's isn't the black-art that I thought it was.

http://www.fpga4fun.com/ is a nice site with stuff that novices can have a go at creating.

There's also a sister site (http://www.knjn.com/) where you get hold of inexpensive FPGAs for tinkering with.

I agree .. it's less interesting - but I suppose the benefit of having an FPGA on-board is reduced development time (and cost) for the hardware manufacturers. Once they've created their product - and licensed the necessary cores .. they're going to try their damnedest to keep the unit sealed.

End-users, sure, but developers is another story completely. I'm sure there will be Linux libraries to access the FPGA directly, within a few weeks/days :P

The FPGA fabric will also have to be configured whenever power is lost. This probably includes the low power states of the Atom since the FPGA wasn't designed to support it. It would make sense for this to be part of the BIOS-level code since the FPGA is useless until configured.

There is a savings in board space, but, otherwise, this solution provides no additional value. You can already connect an Atom processor and FPGA through PCI Express.

The configuration would be saved in Flash memory and loaded at boot time. Also, you'd need to reboot the FPGA each time a new configuration would be written in.

I am not yet aware of FPGA-like chip architecture that can be reconfigured dynamically.

You may well be right, although it seems a huge missed opportunity for the platform in all sorts of hardware acceleration applications.