HardDrive, from developer Mitchell Cohen, is the latest app to join a growing list of file transfer apps. HardDrive is a rudimentary app for grabbing files from your desktop and storing them on your iPhone or iPod touch so you can transport them to another desktop or device.
HardDrive works over WebDAV (short for Web-based Distributed Authoring and Versioning), which is typical for these kinds of apps. WebDAV is an extension of HTML often used to transfer and view files in a Web browser. It works over Mac, PC and Linux machines.
Many of these apps also support Bonjour, Apple's protocol for discovering and sharing devices on a LAN. HardDrive does not use Bonjour, however.
One difference I've found in basic file transfer apps is the Web browser interface. Some are fancier looking than others, but they all do the same job: Enable you to see what files are on your iPhone or iPod touch and desktop and shuttle files back and forth. Both device and desktop must be on the same Wi-Fi network.
HardDrive is as simple to use as any other of the file transfer apps I've tested: Launch the app, and it will search for your router, connect and then display the handheld's IP address and a port to connect to. Enter that address into your browser and a simple Web page pops up where you can move files one way or the other.
Your first step with HardDrive is to drop some files into the app. Then go to another machine, repeat the connection process and transfer the files to the desktop.
Simple, but limited. HardDrive's sole purpose is to move files from one place to the other. The app does not have any provision for you to view your files while they're on your iPhone or iPod touch, as many other apps allow.
For the $1.99 price tag for HardDrive, I would recommend Headlight Software's WiFi Disk instead. In addition to file transfer, it gives you the option of viewing images, PDFs and all other file formats the iPhone supports and editing text and HTML. You can also drag and drop files using FTP. It's a far superior (and better-looking) app.