The Thecus N2100 is a network storage appliance, featuring an Intel IOP ARM CPU; two internal SATA drive bays; several USB 2 ports; two gigabit NICs and a miniPCI slot.
For a few years I used mine with two Western Digital WD4000KS 400GB SATA drives in a RAID-1 configuration using Linux software RAID and Debian GNU/Linux instead of the stock firmware.
One of the biggest draws to this particular unit was the ease with which you could install a stock Debian onto the device. Tbm has some detailed instructions.
It was very helpful to add a hardware serial port, particularly when the OS went wrong and booting normally was no longer possible. David Karlström has some instructions on where to solder here.
The biggest flaw with the device was thermal issues when running two hard drives. My two drives regularly reported temperatures of around 50-55° centigrade, which was the maximum supported operating temperature of the drives. Perhaps it's no surprise, but I went through quite a few drives before giving up on the device.
I only got the temperature to stableize at this level by replacing the plastic lid with a tin biscuit lid, which was a more efficient conductor. With the default lid, the temperatures hit 60° centigrade and kept climbing (I powered the unit off at that point).