At the moment we don't even have any ides about the hardware it is supposed to run on. Maybe some of the beta testers could enlighten us as to the hardware they used.
If your machine will run eCS, it will run ArcaOS. If your devices have a driver today, ArcaOS will use the driver (even if you need to supply it yourself). Be aware, that a few drivers are not being included because of licensing concerns, but that doesn't mean they won't work, if you want to install them. If your machine will not run eCS 2.2b2, it is unlikely (but not impossible) that ArcaOS will run on it.
For my part, I have tested on:
-Lenovo ThinkPad T510. Intel.
-Lenovo ThinkPad L530 (UEFI). Intel.
-Asus M3A78-EM quad core. AMD.
-Asus M3A78-EM triple core. AMD.
-Dell Dimension 4300. AMD, I think.
-VirtualBox, under win 10, using various configurations.
I intend to install on:
-My antique IBM ThinkPad A22e. Intel. (eCS 2.2b2 works as well as it can with only 256 meg).
-My main system Asus A88XM-A (UEFI). AMD. (eCS 2.2b2 works pretty well. I expect that ArcaOS will be better).
when they fix a couple of problems in the installer, that are proving to be difficult.
I must say that the final product, once it is installed, is running very well. IMO it is definitely a step up from eCS 2.2b2. The new installer is being somewhat stubborn, but it will be in shape, when ArcaOS is released.
Can it run the hard disks in AHCI mode or do they have to be set to IDE?
Arca Noae developed the AHCI driver, so it will be included. To be specific, if the driver is in the Arca Noae driver pack, it will also be in ArcaOS.
How well does it work with UEFI and what setting are important?
As long as the machine BIOS has "Legacy Mode", it should work. Apparently, there are a few machines that don't have that feature.
Will we get answers or will there be a deathly silence aka eCS?
That depends on whether they have carted Lewis off to a padded cell, or not. He (and others) is working his tail off, trying to get this right.
To be quite honest, the best answer is "You won't know, for sure, until you try it". That is pretty much the same as it has always been with any version of OS/2, and any new machine. There are always surprises. More often good, than bad, in my experience.
You will probably want to install on a test machine, or in a virtual machine, to see what the installer does, before you try it on a live machine. The installer is a little different, but similar, so users who are familiar with the eCS installer could easily get themselves into trouble, if they don't pay attention to what they are doing. As usual, trying to install, when windows, has hogged the whole disk, is going to be "interesting", but the tools to do it are there, and it has always worked, for me, after I figured out what needs to be done. As usual, be sure that you have a GOOD backup, BEFORE you mess something up.