Computer^News^FAQ: AirDrop

How to use AirDrop over Ethernet and on older Macs running Lion

12:33:00 PM

AirDrop is a new feature in Mac OS X Lion that makes sharing files between Macs easier than ever. There are no accounts to sign into, networks to connect to, or preferences to set up. Some Macs don’t support AirDrop, though, and sharing over Ethernet isn’t possible by default.

Transferring files from Mac to Mac is so easy in Mac OS X Lion that there’s barely anything to it. Just go to the AirDrop menu in the Finder sidebar on both Macs and they will automatically find each other. Next, drag one or more files to the icon of the computer you’re sending them to. The person on the other end will approve the transfer and that’s it!

While the beauty of AirDrop is its simplicity, that doesn’t mean there aren’t caveats. For example, the awesome technology that lets AirDrop work without both Macs being connected to the same wireless network (or any network at all, for that matter) also makes the feature exclusive to recent Macs. Apple has a rundown of Mac models which support AirDrop on their website and the list is limited to those that have a special kind of wireless chip inside them. AirDrop relies on Wi-Fi’s PAN (Personal Area Network) interface, which is capable of establishing peer-to-peer connections. But what if your Mac doesn’t support PAN, even though you’re running Lion? A couple lines of code will keep you from feeling left out.

Launch Terminal (located in Applications > Utilities) and paste the following command:

defaults write com.apple.NetworkBrowser BrowseAllInterfaces 1

Press Enter to run the command.

Next, paste this line in Terminal to restart Finder:

killall Finder

Press Enter again and you’re ready to go!

Let’s say you have two Macs running Lion – one that supports AirDrop out of the box and another that is unsupported. If you’re going to be using this technique to share files between them, it’s a good idea to follow steps 1-4 on both computers. You can always reverse this setting by going through the process again, except replacing the 1 at the end of the first command with a 0.

What exactly have we just done? In essence, we’ve told AirDrop to work over any kind of network, not just a PAN. The only difference is that now both computers need to be connected to the same local network in order see each other and transfer files. So you can have one Mac connected to your network over Ethernet and another connected via Wi-Fi. Perhaps both have Ethernet, or maybe both have Wi-Fi. Whatever the combination, it’ll work just the same.

One thing to keep in mind is that Apple likely chose to only allow AirDrop to work over PAN connections because they are heavily encrypted. Whatever files you transfer using AirDrop with its default settings are secured and safe from snoopers. With the technique in this tutorial, you’re getting more flexibility at the cost of security. Files are only as safe as the network you’re connected to. If it’s your home network, it’s probably no big deal. If you’re using the public Wi-Fi atmake sure you’re not sharing anything important.

AirDrop

How to encrypt an external hard drive in Lion

8:26:00 PM

FileVault 2 not only encrypts your Mac’s internal drive, but it can also encrypt external drives connected via USB and FireWire (and we suspect you’ll be able to encrypt external drives connected via Thunderbolt, but Apple’s documentation doesn’t specify this). However, external drives must be formatted using HFS+. If you have an external drive you want to use with both Windows and a Mac, you have to use the FAT file format, and you can’t encrypt it.

To encrypt your external drive, you need to use Disk Utility (/Applications/Utilities) to reformat it. You can’t encrypt a drive that has data on it—that’s a major drawback if you have an existing hard drive with a ton of data and you want it encrypted. If you want to keep the data, you need to back it up and then copy it back to the drive after the reformatting.

One major caveat: During our testing, encrypted external hard drives could only be used on other Macs running Lion, and not with older versions of OS X. When we connected a drive encrypted using Lion’s Disk Utility to a MacBook Pro running Snow Leopard, a message appeared, stating that the drive required OS X 10.7.

Disk Utility

To encrypt an external drive, connect it to your Mac, wait until it mounts on your desktop after you turn it on, and launch Disk Utility. You’ll see a left column that lists the storage devices on your Mac. The first device is your internal drive. Your external drives should follow. Select the drive you want to encrypt. Then click on the Erase tab in the section to the right.

In the Format pop-up menu, you’ll see two new disk formats available to you, in addition to the standard Mac OS Extended (Journaled), Mac OS Extended (Case-sensitive, Journaled), MS-DOS (FAT), and ExFAT. The two new formats are Mac OS Extended (Journaled, Encrypted), and Mac OS Extended (Case-sensitive, Journaled, Encrypted).

In most cases, you should pick Mac OS Extended (Journaled, Encrypted). The other encrypted Mac format lets you give files the same names but with different letter case treatment. (For example, both files named 2011taxes.numbers and 2011Taxes.numbers can exist in the same folder.) You also need to provide a name. Click Erase.

Set a password

A window will appear, confirming that you want to create an encrypted volume. If so, you need to enter a password. You need to enter this password any time you mount the drive, so be sure to memorize it.

Once you enter and confirm the password, click Erase. This will start the formatting process, which will take several minutes. If you don’t want to encrypt the drive, click Cancel.

Enter password

Once the drive is formatted, you’ll need to enter a password to access it. Your files will be automatically encrypted and decrypted. If you dismount the drive, you’ll need to enter the password when you try to mount it again on your desktop. If you enter the wrong password or don’t enter one, you can’t access the data.

At the password-entry window, you have the option to save your password in your keychain. This will allow your drive to mount without needing your password for that particular Mac that’s storing your keychain. If you try to attach the encrypted drive to, say, your friend’s Mac, which doesn’t have your keychain information, you’ll need to enter a password to access the drive.

AirDrop

How AirDrop makes file-sharing simple

8:13:00 PM

Moving a file from one computer to another remains as big a pain today as it was decades ago when network file-sharing first became common. To move a file from Computer A (your MacBook Pro, say) to Computer B (a colleague’s or family member’s Mac mini, for instance), you have to ensure both machines are on the same network or visible to each other over the Internet. Then you start up File Sharing in the Sharing preference pane, and make sure the other person has the correct permissions to access the folder or volume containing the file. Then, on the other machine, that person (it could be you) selects the networked file server, enters login credentials, and navigates to the file to copy it.

Lion’s AirDrop feature is supposed to cut through all that nonsense and make moving one or more files between two computers a breeze. You just open the AirDrop window (click its name in the sidebar of any Finder window), and drag files onto the icon of a nearby user (who also has the AirDrop window open). They agree to accept the files, and—voilà!—the transfer happens.

But how does AirDrop accomplish this apparently seamless magic? By taking advantage of a not-so-new bit of Wi-Fi technology that allows computers and other devices to connect to one another via peer-to-peer networking. Computers connecting via AirDrop don’t have to be connected to the same Wi-Fi network. They don’t require an ad hoc network or software base station. AirDrop bypasses all that.

The right chips

What AirDrop does require is a Mac with one of the newer Wi-Fi chips—specifically, those that support the Wi-Fi Direct networking system (or similar technology that predates its standardization). Wi-Fi Direct has been around in industry-approved form since 2009. It enables devices to establish simple peer-to-peer connections; at the same time, it supports strong WPA2 encryption. It also allows devices to advertise their available services to other pieces of hardware. For instance, a printer with Wi-Fi Direct could broadcast the fact that it was a printer—even its model number for the purposes of loading a driver—while a cell phone might tell nearby devices that it can transfer files and be used as a relay to access the Internet.

Most popular Wi-Fi chipsets—including some that Apple has used for years—support Wi-Fi Direct. But even though Apple and Microsoft sit on the board of the Wi-Fi Alliance, which developed the underlying technical standards and certification regime, support in operating systems has been lacking. You can’t find it in Windows 7 or Lion, nor in any mobile operating system. For AirDrop, Apple is using just a subset of Wi-Fi Direct’s features; strictly speaking, AirDrop isn’t actually compatible with the standard.

Apple began to include compatible Wi-Fi chips in some of its Macs three years ago; but as recently as a year ago, some Mac models still didn’t have them. Unless your Mac has the correct Atheros or Broadcom chip, you can’t use AirDrop. Apple’s AirDrop troubleshooting page lists the Macs that support the technology:

o MacBook Pro (Late 2008 or newer, but not 17-inch Late 2008)

o MacBook Air (Late 2010 or newer)

o MacBook (Late 2008 or newer, but not white MacBook Late 2008)

o iMac (Early 2009 or newer)

o Mac Mini (Mid 2010 or newer)

o Mac Pro (Early 2009 with AirPort Extreme card, or Mid 2010)

Of my five home and work Macs, only two have the right chips, even though they all meet Lion’s other hardware requirements.

The hit-or-miss availability of AirDrop has made some Mac owners mad, and they’ve been venting their spleen in online forums and news stories. People rightly complain when a marquee feature of a new OS isn’t available uniformly. Some have wondered why Apple didn’t make AirDrop available over older Wi-Fi or on Ethernet connections. The answer is that AirDrop isn’t based on standard networking technologies; it’s peer-to-peer. Apple would certainly have made more friends by adopting the approach of DropCopy (, free for one to three computers), which runs on standard network connections or over Bonjour.

Despite its shortcomings, I see AirDrop as a sign of things to come. As more new Macs are sold and old ones die or are put out to pasture, more and more machines will support AirDrop. As modern networking chips become more common, Apple (and others) could implement Wi-Fi Direct fully, which would make a host of common networking tasks simpler. AirDrop (or Wi-Fi Direct) could also find its way into iOS and other mobile operating systems. However it happens, we’re likely to find AirDrop-style peer-to-peer hookups more routine and more consistently available as time goes on.

Computer^News^FAQ

How to use AirDrop over Ethernet and on older Macs running Lion