1. You will need essentially any dual-core CPU running at 1.5 GHz core frequency at least. The primary testing PC is running on Celeron J3455 CPU and development is done on RyZen 5 3600. Even old CPUs like Pentium 4 or AMD E-350 might be OK.
2. Anything from 1 to 16 Gb of RAM should be enough, depending on the amount of data you process.
3. A DAQ card supported by Comedi is required. Please see the list, and if unsure, get in touch with a local guru or me.
4. Linux with installed Qt 4.5 (switch to Qt 5 pending) and Comedi. The development is done on a PC running the most recent Kubuntu Linux. You might have least trouble if you use it or any other Debian-based distribution with KDE as desktop environment.
5. The program design philosophy bases on working from RAM. Therefore I would not be surprised if someone would run it from a server - or an USB stick!
6. High quality power supply unit is essential for low-noise recordings. My personal recommendation will be to look at the 400-500 W PSU from the upper half of the price range; I tend to prefer FSP brand but other might work too. Just don't go for the cheap ones to be safe.