Apple's Time Capsule is an ideal backup for anyone with a Mac - especially a MacBook, MacBook Air or MacBook Pro. Windows users may be less enamoured, however.

One of the biggest selling points in Mac OS X 10.5 Leopard was the inclusion of Time Machine, a nifty new app aimed at making that most onerous of tasks - backing up data - not only easy to do, but fun.

For laptop users, however,Time Machine offered something of a conundrum. To back up files, you still had to plug in an external USB hard drive - meaning you lost out on one of Time Machine's best features: the ability to back up your data continuously in the background without any extra work by you, the user.

Now plugging in an external drive may seem like a minor task, given the obvious advantages of having all of your files, photos, songs and applications safely backed up. Nonetheless, it was a hurdle. And since 90 percent of Apple's customers told the company in surveys that they don't back up data regularly, any hurdle is one too many.

That's where Time Capsule, which was announced at the MacWorld Expo in January and is now on store shelves, comes in extremely handy - especially for laptop lovers. By allowing wireless backups, it letsTime Machine shine for those of us who don't want to lug around a backup drive or tether our laptops to one sitting on a desk somewhere.

Apple offers two Time Capsules: The 500GB model sells for £199, and the 1TB version goes for £599. Both in effect cut the proverbial USB cord when it comes to backups.

AirPort Extreme on steroids

We've been using Time Capsule for a few weeks now, courtesy of Apple, and have found it to be an ideal backup for anyone with a Mac - especially a MacBook, MacBook Air or MacBook Pro. Not only does it serve as an 802.11n Wi-Fi router, beaming the internet throughout the house or small office, but it also marries that router with a server-grade Serial ATA hard drive spinning at 7,200rpm.

(Incidentally, Windows-based systems - and Macintoshes that haven't been upgraded to Leopard - can use Time Capsule for wireless network access. However, these machines don't have Time Machine, which only comes with Leopard, meaning they're missing a key piece of the backup equation.)

The device itself it looks a lot like an AirPort Extreme on steroids - it's housed in a flat, gleaming, all-white square case that's about 177mm wide and about 25mm high. It's also noticeably heavier than the AirPort Extreme, no doubt because of the hard drive inside.

Time Capsule offers the usual complement of ports in the back that allow you to share an ethernet internet connection with three other computers and plug in a USB printer for shared printing. The only functional difference between it and an AirPort Extreme router is the ability to store data.

You can set up Time Capsule in one of two basic ways: as an all-in-one solution in which it serves as both your wireless router and your backup drive, or as an adjunct wireless drive that connects to your current network.

If you're still using an old 802.11b AirPort base station - or relying something more PC-centric such as a wireless router from Linksys or D-Link - and you're looking for something simple to set up and use, you'll want to go with the first option. That's because Time Capsule allows you to take advantage of the greater data-transfer speeds offered by the newer 802.11n Wi-Fi standard while at the same time adding storage to your network.

An easy setup

Setup is simple. Plug your ethernet cable into the Time Capsule, make sure it has a valid IP address (you may need to restart your Digital Subscriber Line or cable modem first), launch the AirPort Utility, and set your network preferences to your liking. Then launch Time Machine, which will recognize the hard drive inside the device and allow you to designate it as your backup drive. Select "Back Up Now", and sit back and wait. And wait. And wait.

According to Apple, you should plan on waiting a few hours while Time Machine does its first backup. Since it's copying all of your files wirelessly, this process will take longer than doing so over a hardwired ethernet connection. Apple's advice: Start your first backup before you go to bed and let it run overnight. After that, each backup is incremental and takes no more than a few minutes, depending on how many files have changed since the last backup was done.

We can vouch for the amount of time needed for the first backup, which we started one evening just before 8pm. We needed to back up just over 68GB of data on a MacBook Pro. Since the network we used is a mixed 802.11b/g/n network, and the Time Capsule was 4.5m away from the computer - and on the other side of a wall - transfer speeds were slower than if we had used 802.11n only with the device and the computer close to each other. It took all night for the backup to complete. But when it was done, all files had been safely duplicated.

If you're interested only in adding wireless storage to an already-existing 802.11n network, just plug the Time Capsule into a wall outlet, launch the AirPort Utility, set up the device to join your network, and then use Time Machine to back up your files. No major network revamp is needed, although you will have to "switch" between your current network and Time Capsule the first time you add it to your network.

We used the "Manual Setup" option to make sure the Time Capsule settings matched those of my network; just make sure you choose "Extend a wireless network" in the Wireless Mode drop-down menu. We used this setup when connecting Time Capsule to my mom's pre-existing AirPort Express network - and to my own AirPort Extreme network - and it showed up on each network without a hitch.

Two storage options: official and not

If you just want to use Time Capsule to back up your data wirelessly on an existing 802.11n network - and you already have an AirPort Extreme base station - the decision-making can get a bit complicated. You actually have two options: one official, one unofficial. The official one is to buy a Time Capsule and just add it to your current network as described above. Or - and this has been a bone of contention in recent months for Leopard users - you can plug an external USB drive into an AirPort Extreme and use that "AirPort disk" for backups.

This feature, which Apple does not yet officially support, was made live last month with the release of updates for AirPort Extreme and the AirPort Utility application. The move basically followed through on a promise that CEO Steve Jobs made last year before Leopard was released. At the time, he said AirPort disks would work with Time Machine. But that feature was pulled from Leopard before its release in October, to the annoyance of a lot of Apple users.

Although that function has been turned on (and is exactly how we use Time Machine at home), Apple does not yet officially offer support for it. In fact, the updates released last month made no mention of AirPort disks. Users first found out they could access hard drives attached to AirPort Extreme base stations through Time Machine only after the updates came out.

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