Exactly this.
I wonder what the factor is that hinders gigabit ethernet and especially multiple sata ports.
My pogoplug actually has an onboard sata port so it should be possible to integrate those without choking the arm board or running up hardware prices.
It depends on the SoC used. Some will have 1 or 2 SATA controllers on board. This board is based on the Exynos 4412 which I don't think has SATA controllers on board (can't find a full datasheet). This means adding them externally, not big deal right? But, 99% of SATA controllers today are built to talk PCI-Express, and the Exynos SoC doesn't speak PCI-Express! We're screwed...
Basically the same thing happens with gigabit Ethernet (and USB 3.0). Unless the SoC has the controller on-board or has PCI-Express (few do) there really isn't a way to plug the external controller into the SoC. 10/100 Ethernet is slow enough that you can pump its data in and out of the SoC using a SPI port and get most of the speed and many SoCs now have a 10/100 controller and USB 2.0 controllers on board. There is no spec limit to the speed of SPI but its a single ended 2 wire protocol limiting its realistic usage to the several tens of Mbit/sec.
The problem is that there is no commonly accepted, generic, very high speed I/O protocol for embedded devices so if they choose not to implement PCI-Express your left without a way to pump information into and out of the SoC at fast enough speeds to support these new interfaces.
Exynos is a brand name of the family, not a single product. The Arndale has the Exynos 5250 SoC (dual-core A15) not the Exynos 4412 (quad core A9) which is used on the board mentioned in this thread.
You need to include the numbers when you're talking about these parts :-) Arndale is Exynos5, which has a different CPU and peripheral set to Exynos4 (which is what this board uses).
I think it's simply that most of these devboards are produced by the SoC manufacturers with the idea of popularising/making it easy to develop products for their SoC. So the peripherals you get are the ones the SoC has, and traditionally most of these SoCs are aimed at the mobile space, which doesn't have SATA or ethernet or PCI (ethernet on these devboards is often USB-ethernet). As the A15-based SoCs (eg exynos5) appear I'm hoping to see more SoCs aimed less solidly at the mobile market, and with a wider mix of onboard devices.
