In response to a frequently asked question... I wrote the following discussion of using Time Machine versus SuperDuper for backing up a Mac. These two software programs are both good and reliable but they work in different ways and have different pros and cons. We've discussed this in club meetings more than once. But since I just wrote it down again, I thought I'd post it here. SuperDuper is the "cloning" software I've been using but there are a number of other programs (notably Carbon Copy Cloner) that do essentially the same thing and this discussion applies to them equally.
SuperDuper is available here: http://www.shirt-pocket.com/SuperDuper/ ... ption.html
Carbon Copy Cloner is here: http://www.bombich.com
Time Machine comes free as part of OS X and is in the Applications Folder on any Mac sold within the last 4-5 years.
Using Time Machine:
Time Machine keeps incremental backups but not a complete, bootable, version of your hard drive. What does that mean? It means it keeps a "snapshot" of exactly what your drive looked like each hour of the past day. Each day of the past week. Each week of the past month. And each month of the past year ... until it runs out of disk space. At which point it should (when all works properly) start deleting the oldest backups and continue ad infinitum. Time Machine is best at retrieving individual files. Because it can go back in time, it is particularly valuable for retrieving indvidual files or folders that you had last Tuesday and now they're gone. It also has the strength of running continuously, unobtrusively in the background. You turn it on and forget about it. It's good for people too disorganized to think about backing up. It has one particular weakness... Time Machine does not make a "bootable" clone of your computer. It has a set of multiple snapshots going back into the past. But you cannot hook the Time Machine up to another Mac and have it boot up that computer and operate like your own machine. And it cannot as easily create a "Restore" of all files when your hard disk crashes. It can be done, but it's a bit of a contortion to do it. And of course, if your disk crashes, you are at that point 'between a rock and hard place.' Not a good time for surprises or uncertainty.
Using SuperDuper (or Carbon Copy Cloner):
SuperDuper makes an exact bootable clone of your complete hard disk. What does that mean? It means it makes an exact copy of every file and every folder on your hard disk. Every application, every aspect of the System software. It is complete and perfect in every way. You can take your backup drive to any other Mac, anywhere in the world (so long as that Mac is capable of running the operating system on your clone), plug it in, the disk will spin up and you will be looking at your own home computer exactly as it was when you last backed up. All the files will be exactly as you put them. All the programs will open and run correctly. Moreover, if your computer's hard drive has crashed and become unusable for any reason, you can simply buy a new hard drive, install it in your computer, and then RESTORE the new hard drive from the contents of your backup. SuperDuper does this miracle in about 30 minutes leaving your new hard drive perfect and exactly as it was when you backed it up. The SuperDuper disk volume is "Finder readable." In other words, you can open the SuperDuper disk drive, open the folders there, and drag something you've accidentally deleted SINCE YOUR LAST BACKUP back to your computer's hard disk. But unlike Time Machine, SuperDuper does not keep a "snapshot" of past times. It only has a copy of the very last time you backed up. The other weakness of SuperDuper is that you have to remember to use it! The paid version of SuperDuper (which costs $28) has a "scheduler" in it, so that you can, in theory, leave it running all the time and it will automatically back up your hard drive each night at 2 AM. Many people use it that way. I don't. I'm a fanatic about backing up. I backup each day for sure. And I backup immediately after I've created any large or time-consuming project that I've just saved. After I back up, I turn off the drive and hide it in a safe place. This lengthens the disk drive's life because it's only used a few minutes each day. But I am completely and safely backed up. But if you forget to do this... or can't be bothered... then this method is not for you.