The B-type USB port labelled 'USB-PC' is for connecting the A110 up to a PC (funnily enough), specifically for accessing the internal hard drive - if you've chosen to fit one. It enables you to quickly and easily copy your media to the drive just like it were a conventional external hard drive. The only headache is the installation of a special driver to make the drive appear in Windows and OS10 operating systems (EXT2FSD is one that's suggested for Windows).
Meanwhile, the Ethernet connection, which is only 10/100Mbps, provides connectivity for the A110's host of network capabilities. These include the ability to access the internal hard drive over a network as you would a NAS box, you can also run a bittorrent client, FTP server, and there are all manner of internet services including youtube, Flickr, picasaweb, RSS feeds, Shoutcast, SayaTV, and many more besides. There's no built in wireless but many wireless USB adapters will work and you could also use a wireless to wired bridge.
Getting a hard drive inside the A110 is as simple as removing the four thumbscrews holding the top down, plugging the drive in, and screwing it in place using the provided screws. There are mounting points for both 2.5in and 3.5in drives providing plenty of flexibility. The drive connection is SATA, which is another change from the A100 that used PATA, so should fit the vast majority of modern drives.
As you can see, there's not much to the A110 once you get inside. The vast majority of its trickery is performed by the chip that sits under the large black heatsink. This heatsink makes contact with a thermal transfer pad on the underside of the lid to pass the not inconsiderable heat generated by the processing chip onto the A110's casing. For this reason the whole unit can get quite warm even when sitting idling and we've read reports of overheating. Some people have retro fitted small fans to help air circulation and one could also add a more effective thermal compound to the underside of the lid to aid cooling. We, however, experienced no heat related stability issues whatsoever.
Once connected up, initial bootup can take quite a while but, from there on in, flipping between standby and On is very quick. The first screen you'll see lists the source device options that are currently available so if you have a hard drive installed, a USB device plugged in, and a network connection present, you'll have a choice of these three. Choosing network requires you to further choose which network device to connect to, whether it be a NAS box or shared folder on your PC.
From here on in you'll be greeted by a home screen that gives four file-type options; video, music, photos, and file. The first three are self explanatory but the last one is less so. Essentially, it's for accessing anything else like executable files (some of which you may be installing on the system) or documents.