At first, the iTwin seems to solve a problem that's already been taken care of--sharing and syncing documents remotely. But while services such as Dropbox are useful, you're limited to just 2GB before you have to start paying a monthly fee. For $99--with no additional fees or subscriptions--iTwin lets you create a secure link over the Internet between your home and work PCs, creating a single, unified storage structure that's only limited by the size of your computer's hard drive. While you have to remember to pack this tiny USB dongle when you travel, it's as simple as it is effective.
Design and Setup
The iTwin looks like a long USB stick, except it has a male USB jack at opposite ends, sort of like a gag pencil with two erasers. A small LED on each half lights up when it's connected to a PC.
Setup is simple. Stick the iTwin into a USB slot in your home PC--it doesn't matter which end--and iTwin's software will self-install from the stick. On a Mac, you may have to download the iTwin software; the company is working to include it in future iterations. While that's annoying, Mac installation presented no problems. Afterwards, an iTwin disc image appears in Windows Explorer or, on a Mac, in Finder. You are now ready to create a single centralized set of folders that can be accessed from anywhere on any other PC.
Drag files you'd like centralized to the iTwin as you would to any attached hard drive. Since you do not store actual files on iTwin--just links to files--storage capacity is only limited by your computer's hard drive size. And because you're not copying actual files, the "copy" process takes no time at all.
Now, snap the iTwin in two. Slip the second half into a remote PC, and the iTwin will perform the same self-installation as the double-stick did in your main PC. Better yet, the iTwin is platform-agnostic; you can mix Windows and Mac PCs on the same iTwin mini-network. You can also use more than one iTwin on a single computer, so you can share files with multiple notebooks.
Once you plug the second half of the iTwin into your laptop and the software is installed, two folders are created on both linked machines: Local and Remote. On your host PC, your linked folders are in the Local folder, an on your laptop they appear in the Remote folder. Click on the Remote folder on your laptop, and you'll see the set of files you dragged to it on your desktop PC.
However, you may have a separate set of files and folders on your laptop that you want to access remotely and keep separately from the files on your desktop PC. In this case, these files are stored in the Local disk image on your laptop and appear in the Remote folder on your desktop.
This seems a bit confusing; it would seem easier simply to keep all these files in a single folder. But as you long as you remember originating files are Local and accessed remotely from the (duh) Remote folder, you'll be okay.
Once the two iTwin halves are linked, you're emailed a Remote Disable Code, which you can use to disable a lost or missing iTwin half. If you lose the second half, you can buy a $50 replacement that can be paired with the remaining half.
When connected, the two halves of iTwin generate a shared random 256-bit AES (Advanced Encryption Standard) key each time they are paired and plugged into a computer. A Smart Crypto key using HTTPS (RSA 1024-bit, 128-bit RC4) protocols is used to encrypt the data traffic between the two halves. You can also set your own password.
The iTwin detects almost all types of proxies, firewalls and NATs (Network Address Translators), and self-configures. If reception of files on either iTwinned-connected PCs is blocked by one of these security measures, the iTwin uses Amazon EC2-based servers to relay the encrypted data traffic. Files are never buffered--if a file can't be transferred, it stays where it is until it can be .
As long as both our host and remote PCs were turned on and connected to the Internet, we could access and open files from the Remote folder as if they were sitting on our desktop. We could create new documents and save them to the Remote folder--and thereby to our host PC--as well.
Once saved, changes to old files and created new files showed up instantaneously at the other end of the iTwin link. If you want to add files to be remotely accessed, there's no need to re-attach the two iTwin halves. Just drag the new folders or files to the iTwin Local folder on the host PC, and--POP!--they appear in the Remote folder on your iTwin-connected laptop.
Functionally, iTwin works wonderfully. Physically, not so much. You don't want to travel with the iTwin sticking out of your laptop where it can get jammed or twisted. That means you have to carry the tiny thing--somewhere--increasing the odds you'll lose it. iTwin needs to create a key fob case so you always know where the second half is when it's not in your laptop or a remote PC.
While a cloud-storage solution such as Dropbox eliminates the need for the fobs, it has a capacity of only 2GB (in its free version), and is designed more to transfer files between devices than to create a unified file structure. Once you put files in your Dropbox folder, you have to remember to transfer them to your permanent file folders.
Conversely, a networked hard drive creates a centralized file structure, but is more difficult to set up and limits your storage. Unlike an external networked drive, the iTwin doesn't require you to choose where to store your main files, on your desktop or the external drive.
Since iTwin does not actually store files, it can't be used as a backup drive. You should still do an ordinary backup of your files to an external drive or to a cloud backup service.
Like other technically sophisticated gear, iTwin is deceptively simple to use and inexpensively solves one of our most vexing modern PC problems. For those who need to keep files synced between two computers, the iTwin is highly recommended. Just don't lose the second half.