Editor’s Note: The following article is an excerpt from Take Control of Syncing in Tiger, a $10 electronic book available for download from TidBits Electronic Publishing. The 135-page ebook covers tasks like syncing data between your Mac and mobile phone, iPod, or PDA; explains how Apple’s syncing model works; and provides practical troubleshooting advice.
Tiger puts a lot of power and intelligence behind its syncing services, but it doesn’t offer syncing support to meet all contingencies. When Tiger falls short, you have to jump off the Apple mothership and board a third-party craft.
There are all sorts of reasons why you might want to, ahem, sync different:
Take Control of Syncing in Tiger addresses all of these situations. However, in this excerpt, we’ll focus our attention on using third-party apps to sync files. Tiger’s built-in file-syncing capabilities pretty much start and end with the .Mac iDisk. If iDisk’s characteristics and limitations don’t meet your particular syncing needs, you must find a third-party file-syncing solution.
In order to sync files between two or more Macs, the Macs involved must be connected in some way. Most of the file-syncing applications, described later in (what else?) Review file-syncing applications, sync between two folders—as a rule of thumb, as long as those two folders can appear in the Finder of the Mac running the sync application, you can sync those folders.
Notice the phrase in the preceding paragraph, the Mac running the sync application . This is a key concept for most third-party sync utilities: with few exceptions, file-syncing utilities run on one Mac, and use standard file reading and writing procedures to sync files with the other Mac; the second Mac runs no special file-syncing software of its own. This is sometimes referred to as a master/slave relationship, with the Mac running the sync program as the master.
Here are the two most common connection methods used to connect two Macs for file syncing:
FireWire Target Disk Mode: This method turns one of the Macs into a true slave—it becomes nothing more than an external FireWire drive connected to the master Mac.
Personal File Sharing: You can connect Macs on a local network with Tiger’s Personal File Sharing, which allows you to mount folders from the sharing Mac on the master Mac—note that the slave Macs do the sharing; the master Mac doesn’t have to. To turn on Personal File Sharing on the slave Mac, do this:
Now that the slave Mac has sharing turned on, you can mount it on the master Mac’s Desktop:
Tip: For an extremely fast way of sharing files, you can create a local network using FireWire; this Web page for details.
You can find quite a few file-syncing utilities with a quick Internet search. I’ve chosen five such utilities to describe here, with hopes that one or more of them might meet your syncing needs. If you have trouble deciding on one, Pick a file-syncing application, which follows this list, should help you out.
Here are my five sync utility picks:
If you want to keep your iTunes libraries synced between two or more Macs, the latest version of Martian Slingshot has added that neat trick to its repertoire.
You can download a free copy of Slingshot that provides for one publisher and one subscriber if you wish to try it out. Slingshot is one of the few file-syncing utilities that requires the syncing software to be installed on each Mac—for personal use, you can run Slingshot on multiple Macs with no extra license required, but Martian Technology requires a different licensing arrangement for business uses. Slingshot uses Bonjour to detect subscribers and publishers on a local network.
So how do you choose among the applications listed above to handle your own syncing needs? Fortunately, even the most costly of them will set you back no more than a typical gasoline fill-up, and they all either offer free trials or work with limitations until purchased, so you can experiment to find the one that works best for you.
To make the choice, consider the following questions:
How do you connect?
Look for a utility that can handle the transfer of files over the connection method you intend to use. The fastest syncs are with directly connected Macs using FireWire target disk mode, but the most convenient syncs are between Macs on a network, since you don’t have to shut one down, move it, and reboot it. All the applications listed above can handle any volume that mounts on the Desktop either through FireWire or a network connection, except for Martian Slingshot, which works only on a local network.
Are you syncing more than two Macs?
Only Slingshot handles more than two Macs at a time. FoldersSynchronizer and ChronoSync support multiple sync sessions, which with a little organizational work, let you sync multiple Macs in separate sessions.
Will the files be used in more than one location between syncs?
Some syncing utilities, such as Quick Sync, don’t handle the case where two or more copies of a file have changed between syncs, and simply choose to make the file with the most recent changes the current version. You must find a syncing solution that provides a way for you to resolve syncing conflicts easily and reliably. Synchronize! X Plus, FoldersSynchronizer, and ChronoSync each have a conflict resolution feature.
Will you need to automate your syncing?
If so, you may need to keep your sync utility running all the time, or use one that includes an always-running background helper application, so that syncs can occur on schedule (for example, Tiger uses a background application called MirrorAgent to monitor the state of your iDisk). You also need one that can gracefully handle situations where one or more of the syncing participants may not be available when automatic syncs occur. ChronoSync, FoldersSynchronizer, Quick Sync, and Synchronize! X Plus feature scheduled syncs. Slingshot operates in the background on all Macs participating in a sync; those that are unavailable don’t sync until they’re available again.
Will you need to sync metadata as well as the files themselves?
If you have a workflow that requires the file permissions to be preserved or that needs access to your files’ Spotlight comments, you must find a sync utility that manages such metadata. Synchronize! X Plus preserves file permissions, while ChronoSync preserves all sorts of Tiger-specific metadata, including Spotlight comments and extended attribute lists.
Tech note: A Unix utility known as
underlies a number of freeware and shareware file-syncing utilities. According to its Unix
page, “rsync [can] transfer just the differences between two sets of files across the network connection, using an efficient checksum-search algorithm.” If you are seriously geeky, you can put together Unix scripts that use
to sync your files exactly the way you want… but if you’re
geeky, you already knew this.
[ Michael E. Cohen has worked as a teacher, a programmer, a Web designer, a multimedia producer, and a certified usability analyst. He’s the author or co-author of several books; his latest is Take Control of Syncing in Tiger ( TidBits Electronic Publishing, 2006). ]