The 1100 is essentially a dedicated computer that has everything stripped out except what's needed to get it attached to a 10/100 Ethernet LAN and talking to just about any network file system and protocol that you'd want. It runs on a customized stripped-down version of FreeBSD dubbed SnapOS, which should make it fairly robust in terms of both uptime and resistance to hacking exploits.
The other advantage that being FreeBSD-based brings is that you don't have to worry about per-client license fees, as you do with other non *nix-based server products. The 1100 supports file sharing for as many clients as you need... no questions asked or additional money required. SnapAppliance sweetens the deal by including a copy of PowerQuest's DataKeeper - also usable for an unlimited number of Windows clients (more on DataKeeper later).
The 1100's enclosure is about the size of a child's shoebox in footprint, but a little shorter. It surprised me that it weighs as much as it does - 3.5 pounds - but an inspection of the innards revealed that a lot of that is the Seagate hard drive. My 80GB model (the 1100 also comes in a 120GB size) uses a U Series CE 80 5400RPM Ultra ATA/100 drive. It and the processor board are mounted in an aluminum chassis, which is then dressed off with a snap-on black plastic cover.
The processor board uses an Intel Pentium 166MHz MMX processor with 64MB of RAM and just the bare essentials required to interface the CPU to the single 10/100 Ethernet port and hard drive.
The front panel has four status lights - System, Ethernet Link and Net (activity), and Disk activity - with the System light flashing about once per second once the 1100 has booted. The rear panel holds the Ethernet port, Power jack, hardware Reset and Power buttons. I had hoped that the power supply would be internal to the unit, but it's an external brick that's about the size of a typical laptop power supply with cords on both ends.
In general, the 1100 is very quiet (quieter than my Dell laptop!) - at least when the temperature-controlled fan isn't running. Once the fan kicks in, however, it seems to be on more than off, adding one more member to my office's fan chorus.