A reader recently contacted us with a question regarding her decision to recycle an older iMac computer. She wanted to know how she could clear/reformat the hard drive, but didn't have the disks that came with the system. So, we thought we would take a minute to tell you how you can cleanse your hard drives before getting rid of your computer. I'm going to show you how to wipe the hard drive using Target Disk Mode, since this will work even if you don't have the install disks.

Step 1: Get a FireWire Cable
Both of the Macs will need to have FireWire, which means everything between the iMac DV and the current lineup (except for the MacBook Air and unibody MacBook) is eligible. You will also need a FireWire 400 cable so you can connect one end to the old Mac, and the other end to another Mac. If you don't have one of these cables, you can easily pick up one online or at a retail store. If both of the Macs support FireWire 800, you can use one of those cables as an alternative to 400; it will be faster. If one has only a 400 port and the other has only an 800 port, a converter cable (available online for less than $10) is what you need. Once you have the FireWire cable, just simply connect the two computers together.

Step 2: Boot into Target Disk Mode on the old Mac
Shut down the old Mac that will be receiving the hard drive cleaning, and reboot it while holding down the "T" key on your keyboard. After a few moments, you should see a FireWire symbol appear on the screen -- when you see this, you are in FireWire Disk Mode (FDM). When in FDM, your old Mac's hard drive should show up on the new Mac as a connected external FireWire drive.

Step 3: Do some Disk Utility magic
Open Disk Utility.app on your new Mac (located in /Applications/Utilities), and click on your old Mac hard drive in the selection area on the left. Note that you should click on the drive, and not the partition (often called "Macintosh HD") to ensure a complete disk wipe. The disk drive will most likely have a FireWire icon to denote that it is connected as an external disk. Once you select the drive, click the Erase tab, and click Security options.

In this section of Disk Utility, you will be able to select a few different erase options that will also add security to the standard disk erase. First, lets specify a name for the drive -- in the name field type what you would like the drive to show up as when it is erased, otherwise it will default to "Untitled."

Continue reading to learn about security options and how to fully erase the hard drive on an old Mac.

Today is Data Privacy Day, a global initiative to highlight information security rights and practices, especially among teens, professionals, corporations, and the government.

As part of the celebration, TUAW (along with our sister blog Download Squad) has seven good ideas for you about how to keep your data safe and away from prying eyes with Mac OS X Leopard. Also, be sure to browse TUAW articles filed under Security for other tips and alerts about keeping your data safe.

1: Turn on your firewall

Leopard, as we all know, comes with a built in firewall to prevent other computers from connecting to internet-facing ports on your computer. But: Did you know it's turned off by default?

To turn on your firewall, open System Preferences, and click the Security icon. Then, click the Firewall tab. Make sure either "Allow only essential services" is selected, or you can choose to "set access for specific services and applications" yourself.

You can also use "Stealth Mode": when enabled, computers that send data to blocked ports won't even get acknowledgement that the data was received. To enable Stealth Mode, click the Advanced button on the Firewall tab of the Security preference pane, and click the check box next to "Enable Stealth Mode."

2: Set a screen saver password

A feature popular with Windows users, Mac OS X can also lock your screen when your computer sleeps or when the screen saver comes on. Simply open System Preferences, select Security, and choose the General tab. Click the check box next to "require password to wake this computer from sleep or screen saver," and you're all set.

If you have automatic login enabled and click the "require password" check box, Mac OS X will recommend that you disable automatic login. This means you'll have to enter your password to turn your computer on, too; nefarious nogoodniks won't be able to restart your Mac while the screen saver is on to circumvent the need for a password. Good thinking.

A while back we noted that refurbished iPhones still contained previous users' data and that there was no built-in way to securely erase it (though there were some rough suggested work-arounds). With the new 3G iPhone, and lots of upgrading, around the corner the problem seemed more worrisome than ever. However, AppleInsider is reporting that the iPhone 2.0 software will have a solution.

Unlike the present "Erase All Content and Settings" feature in the iPhone Settings, the new version "will wipe data in similar fashion to the 'Secure Empty Trash' function of Mac OS X, by which all data is deleted, unlinked, and then overwritten several times to make it irretrievable by even the savviest of recovery tools." This is obviously good news for everyone looking to upgrade and it should roll out when iPhone 2.0 lands on July 11.

Given all the recent MacBook Pro drama of late, what with overheating issues and all, it might be a good idea to peruse your MacBook/MacBookPro owner's manual one of these days to make sure you've covered the basics, even if most of Apple's care recommendations are obvious these days. Gearlog found a couple of interesting snippets in a MacBook Pro owner's manual that, again, might be obvious to some, but are still good for a refresher. The first is a warning about the use of magnets in the MagSafe power adapter. Apple warns that the end of the MagSafe power adapter and the port on the MacBook could be powerful enough to erase information from magnetic media such as credit cards and iPods, so it would be a good idea to keep these things away from each other.

The second blurb from the owner's manual warns against using a MacBook Pro directly on any part of your uncovered body; these things can get pretty hot (obviously), but this is the first time I've heard of a laptop owner's manual directly warning: "Prolonged contact with your body could cause discomfort and potentially a burn". I wonder if there are any other obvious or possibly interesting snippets in these manuals that most of us have been passing over.

This concludes the end of this public service announcement, thank you for your time.

If you've ever installed an app that can take advantage of .Mac syncing services and then stopped using it or removed it for one reason or another, you might have noticed that its listing in the .Mac System Preferences pane still lingers. This could be a nuisance to neat-freaks, but it could also cause complications in some cases.

Fortunately, a post at macosxhints has done some digging into the matter and revealed a few clues to cleaning up the mess. It turns out that Panic, makers of Transmit, offer a Terminal tip for removing Transmit from the .Mac sync services list. This inspired the macosxhints poster to do some digging to see about other services, so check out their post if you're looking to do some .Mac sync services spring cleaning.