Computers crash or get stolen. Hard disks get corrupted or fail. This is life! So protect yourself.
You can simply back up key files on a CD or online, using services such as Dropbox. To protect yourself seriously, however, is more complicated. But if (when) something goes wrong you will be glad you took the trouble because you can then get up and running again quickly. Here’s how:
1 SYSTEM DISK IMAGE If your computer breaks or your hard disk corrupts (usually just before an exam or presentation!) you need to get up and running on a spare one until yours is repaired. Your own computer has a huge number of refinements and software you have installed over time which will take an age to reinstall. So you need an image of your boot disk which you can quickly restore to a different computer. (The boot disk is the disk or volume that has all the system files necessary for starting (booting) the computer.) This image should also include your applications because these are often laborious to reinstall and you may have lost the passwords. If you borrow a computer you can use this boot disk as if it were your own hard disk.
2 VERSIONS As you work on your project you may make a mistake and need to go back a version or two. When making changes, first save the old version with another name. Be organised about this; for instance, put the date (e.g. 10.08.23_filename) as a prefix, so that when you sort by file name they will be the order you made them regardless of when you last changed them. If you make more than one a day, add a letter: 10.08.23a_filename. If you are working in a team, add your initials to the file name. Where possible put a history of the file at its beginning, which can be thrown away finally. For instance:
10.08.23_filename_gcs: final pages added
10.08.22a_filename_pt: section on Venice Biennale added
10.08.22_filename_pt: first draft made.
3 FILE BACKUPS When you back up files to an external hard disk use incremental backups that save previous versions so, for instance, if you throw away a file by mistake you can look back and find a previous version. Back up the files you are working on every day, or more often as you get near a deadline. Then, if your computer breaks, you can first reinstall your system disk image and then copy back your recent files. (You should also back up your email files regularly.)
4 OFF SITE BACKUPS If you had a flood, fire or robbery, your computer and your backups could both be lost. So keep copies of your system disk image and current files in a safe place in another building—with a friend, for instance.
5 ROTATION Every week or month rotate your disks: back up the disks you have at home and take them to your safe place. Bring home the other disks and back up to them. With this system, there may be a week or month’s work with only one copy, the one you have at home. To protect yourself against this being lost, use an online service like Dropbox to keep copies of the files you are currently working on.
6 ARCHIVE This is different from backups. Here you want to keep the final files of a project, or a year’s correspondence. They are there so you can access them if you need them, but usually you won’t. When you archive a project, make clear which are the final files and (usually) trash all the different versions you made when you were working on the project. This way you keep a neat archive and don’t fill up your hard disk with old rubbish.
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Here is a possible solution. It works for Macs but the principles are the same for Windows.
The ideal setup is 2 small external hard disks to back up your boot volume, 2 larger ones to back up your archive, and a large one for Apple’s Time Machine. (Instead of the 2 small disks you could get 2 big ones and partition each into 2 volumes, one for the boot disk and one for the archive. You can also manage without Time Machine, but it is so convenient that it is worth it if you can afford it.) You also need a safe place away from home where you can store copies of your backups.
To economise on space on your external backup disks, partition the internal hard disk on your computer into two volumes: one as your main boot disk with your system and current documents on it; the other as an archive disk with documents you don’t change often. Say 60-80 gigabytes for the boot volume. This means that when you make a backup of the boot volume it does not take much space and is quick to copy.
Use one of the small hard disks to back up only the boot volume. It does not need to be fast because you won’t access it often. If it is portable you can carry it with you if you travel (but don’t carry it in the same place as your computer).
Using Disk Utility, partition the disk (even if you only want one partition). If you will use the drive for Intel-based Macs only, choose GUID Partition Table; otherwise choose Apple Partition Map. When you have partitioned the disk, select it in the Finder and press Command-I to get information about it. Open Sharing and Permissions and at the bottom make sure that Ignore Ownership is NOT checked. (This keeps all the ownership details of the files on your boot volume correct—otherwise you will not be able to boot from it.)
(Not all portable hard disks that draw power from the computer can work as boot disks. Check that the one you use will work. Some only work if you boot up in a particular way. If this is the case, write the instructions on a label and stick it on the disk. Because you only restore very infrequently you may forget how to do it.)
Use Carbon Copy Cloner (free) to clone (make an exact copy of) your hard disk. On my Mac I clone the boot disk at least once a month so I can easily restore it.
Use another hard disk to back up all your data files. You only need to back up your archive when you add files to the archive, or reorganise it. Use Carbon Copy Cloner to do an incremental backup—not a clone. (An incremental backup only backs up stuff you have changed since the last backup.)
Duplicate these two disks and keep them in a different place, with a friend for instance.
Use another hard disk for Apple’s Time Machine which backs up your current disk automatically. It backs up what you have changed every hour and keeps them for a week, Every week it throws away all but the last of the week and goes on in this way until the disk is full. Then it throws away the oldest week to make room for your new changes. This way you have a few month’s files easily accessible if your computer breaks. (You can choose to include the archive but this will use a lot of space and so reduce the length of time your files are kept. Because you won’t often change the archive files it is best to back these up separately. )
Organise your hard disk so your current files are in one place: in Documents, for instance. Back up these files to an online service, in case your Time Machine hard disk is stolen or there is a fire in your apartment. (If you use AppleMail back up your Mail files as well: they are stored in the Library folder, not in Documents). Backing up online can be slow, so only back up current files. Then, if you need to restore, first restore your most recent boot disk backup, which will be not more than a month old, and then copy back the current files stored on your online backup.
To be ultra-safe one should have 3 sets of disks to rotate. This protects against what happened to someone we know: a computer and backup disk was stolen from his house over a weekend. He gets his second backup disk and borrows a computer onto which he copies his second backup. He leaves his bag with this computer and backup disk in the office, but someone slips in and steals it. EVERYTHING is lost. If you have only 2 backups there is always this period when you are restoring your work and both your backups are in one place.
For more about backing up Macs buy the e-book Take Control of Mac OS X Backups by Joe Kissel.