Although my PowerBook G3 now acts as my main computer, both on the road and on my desk, my earlier PowerBook 5300 existed primarily as a satellite machine. As a mobile Mac it proved invaluable, but at home or in the office it became another flat surface to hold papers and floppies while the battery charged. Switching between machines presented a problem: what's the best way to ensure that my data is up to date on both machines? I found the solution in the aptly named shareware utility Synchronize, which I now use to synchronize files and folders on a variety of machines.
Through a Mirror, Darkly -- Synchronize's functionality is the same as other similar tools, such as Apple's File Assistant: it compares files' modification times and replaces old versions with new ones. This way, if you've changed two separate files on two machines, the end result will be folders containing the most recent editions of each file. You could accomplish this by dragging each file to its comparable destination in the Finder, which automatically compares modification times, but you'd go insane soon after responding to a few dozen "Do you want to replace..." dialogs.
The problem with some synchronization utilities is that they assume you want exact duplicates of your source and destination folders, and will efficiently create folder clones for you. But what if you don't want exact duplicates? What if your Date & Time settings got screwed up on one machine, and your last hour's of work is efficiently overwritten? When I used to synchronize the folder for Claris Emailer 1.0 (which stored each message as its own file, instead of one database as Emailer 2.0v3 does), I once lost a significant amount of email because the PowerBook's date was off. Blind efficiency quickly lost its appeal.
The Power of Choice -- Synchronize offers the same functionality but with much more control. After scanning the directories you specify, Synchronize presents a list of files to copy, with color-coded arrows to indicate which files will be overwritten. Clicking a line representing a file or folder displays modification dates and times, as well as the files' sizes (which can be useful when files' dates are extremely divergent). If you run across a pair of files that seem misdirected, you can choose to remove them from the list. You can also mark files for deletion (both files in a pair are deleted).
Being able to micro-manage your synchronization operations is worth the price of registration, but there are other features which make the program compelling. In some cases Synchronize can be too good at its task, such as copying aliases or invisible files like custom icons. Synchronize's configuration options allow you to specify individual file and folder names to ignore, and you can filter the selections based on label, modification date, file type (such as aliases or invisible files), or parent application. If you regularly synchronize the same two folders, you'll appreciate not having to remove such items manually from the Files to Copy list.
Synchronize can be set to perform brute force copies that create exact duplicates of the master folders, such as when you want to maintain a backup of a folder. Using Synchronize's multiple Start and Completion options, you can schedule automatic sessions that could, for example, mount a network volume in the middle of the night, synchronize files between it and your Mac, put away the volume, and then put your Mac to sleep.
The program stores folder locations and settings in independent Synchronize files, so initiating a synchronization job is usually just a matter of double-clicking its file. You can also set those files to open automatically when you launch the program, which makes all of your frequently used operations ready at the same time.
The only persistent problem I have with Synchronize is the lack of a zoom box in the Files to Copy window. I'm usually comparing at least dozens of files, and the default window size displays less than ten items. Although you can manually expand the window by dragging the lower-right corner, I want to be able to click a zoom box to make the window fit my monitor's height. For a long time I also wished for the capability to synchronize files over the Internet, since Synchronize works only on local volumes and over AppleTalk LANs. Qdea's upcoming Synchronize Pro 4.0 (a separate product, now in public beta) promises TCP/IP synchronization.
Despite my enthusiasm, I don't actually spend much time using Synchronize; it works so well that I can quickly synchronize the files I need and get on with my day. That kind of efficiency maintains its appeal.
Synchronize 3.7 is available as a free 650K download. The unregistered version limits synchronization of folders containing 10 MB of data or less; advanced features apply to folders sized 1 MB or less. Paying the $29.95 registration fee removes the file size restrictions (you may have to increase the amount of allocated RAM depending on the number of files being synchronized), and includes free upgrades.