Writings on technology and society from Wellington, New Zealand

Thursday, October 29, 2009

Why you should back up your computer and how to do it

There is an utterly heart-rending scene in Miranda Harcourt’s autobiographical play A Biography of my Skin in which their family computer’s disc crashes and they lose all their family photographs.

Today on Radio New Zealand National I’ll talk about how to keep your computer backed up. It’s not a hard thing to do. I’ll also have a few other tidbits from the world of technology.

I’ll be on air after the 11am news, and soon afterwards the you’ll be able to download the audio as ogg or mp3.

Q: So, about backing up our computers. That’s one of the things we all ought to do.

A: Absolutely. Let’s just recap how a computer’s hard drive works – that’s the part of it that keeps your files, photographs etc – it consists of one or more discs of magnetically sensitive material, quite like the stuff that recording tape is made of. The disc spins very fast, and it’s read from and written to by a tiny read/write head – actually a very small electromagnet – mounted on an arm which lets it move from the edge of the disc to the centre. By moving the arm and waiting for the disc to rotate the computer can get the read/write head to any part of the disc. Now here’s the risky part. Not only does the disc move very fast, up to 10,000 rpm, but the read/write head on the arm – also moving – has to very close to the surface of the disc for it to work. Now imagine what happens if the read/write head touches the disc.

Q: What does happen?

A: At a minimum, the disc is scratched and the information in the scratched area is damaged or lost. We used to say that the disc head had gone farming, because it ploughed a furrow in the disk. In the worst case, the disk cracks then just disintegrates under the tremendous centrifugal force its experiencing.

Q: It flies apart?

A: Yes. There is not much hope of getting any of your information back if that happens.

Q: What if the damage was more minor?

A: You will still lose part or all of what’s on your hard drive if that happens, and recovering what’s there will be an uncertain and expensive business. Look for Computer Forensics in Google and you’ll find some companies who might be able to help – but their services are not cheap.

Q: What sort of thing could you lose if your computer disc fails?

A: Those of us who run businesses on our computers mostly realize how painful that could be if we lost our files. It might prevent us getting our work done, lose track of what we are owed, or even put us out of business altogether.

But even for most people who don’t run a business on the computer – imagine how distressing to would be to irretrievably lose all your photographs, maybe of your children or your grandchildren as they grew up. Or all the CDs you have put into your computer – legally of course, over the years. Or just the archive of all the email you have sent and received, if you are like me and keep all that kind of thing.

Q: How do you back your computer up?

A: It used to be pretty tedious, frankly. You used to have to burn the computers contents to writeable DVDs or CDs, or in the dark ages – floppy disks. Thankfully we have far better mechanisms available to us now. The best way is to use an external hard drive and copy the entire contents of your computer’s hard drive to it.

Q: An external hard drive?

A: These are things about the size of a paperback book. They plug into your computer’s USB sockets. Some of them have an external power supply as well. They cost about $200 depending on size. You should get one that’s bigger than your computer’s drive, preferably twice as big. You can get them in 1 or 2 terabyte sizes these days. A Terabyte is a thousand Gigabytes, which is comfortably more than most computers’ hard drives, so that’s not a problem.

Then you need some software. Many of the hard drives come with some archiving software. If you use Windows, make sure that the software runs on your particular flavour of Windows, say XP, Vista or 7.

If you use a Mac – you don’t need any more software, provided you are on Leopard or Snow Leopard. They both have Apple’s really slick backup and archiving software called Time Machine built in. If you don’t have at least Leopard or Snow Leopard – get with the programme. Time Machine is worth the upgrade cost alone.

If you are on Linux, have a look at a program called “Back in Time” which gives some of Time Machine’s capability.


A disk crash. Don’t let one ruin your whole year, and backup regularly. Use a USB hard drive like this one. Backup software for Windows and Linux. For Mac users it’s built-in.

posted by colin at 8:16 pm  


  1. I have my older machine backing up my newer machine. Every time I create new documents, programs, photographs or whatever, I run a custom script which uses rsync to mirror the updates to the backup machine—quick and convenient.

    Every now and then I do burn a bunch of CDs/DVDs, and pop them in the bank safe-deposit account. They only charge me a few dollars a year.

    Comment by Lawrence D'Oliveiro — 29 October 2009 @ 1:36 pm

  2. I was wondering about the various ways of backing up data and your comments this morning were very useful. However you didn’t say anything about using internet back up services. I appreciate that there are issues here of storage integrity and access speed but in this area things are changing almost daily so it could be considered a possibility if your files were suitably encrypted. What do you think?

    Comment by John — 29 October 2009 @ 3:41 pm

  3. Laurence

    Yes, rsync is the way to do it if you are geeky enough to set the thing up in the first place! Not to mention having multiple machiens to hand whiohc most people still don’t.


    Backing up to the Internet has a number of issues in my mind. One is the data cap most of us live under. Another is the encryption – I’d want to control that, not just accept whatever the backup company gave me. And you also have to worry about physically where your data is. What is the legal environment it’s under and and what rights and obligations do you have there? Finally you also have to ask yourself what comeback you have if it doesn;t perform when you do want to restore files.


    Comment by colin — 30 October 2009 @ 7:10 am

  4. I’m also a mac user, but I have a PC for a small handful of programs I can’t run on the mac. For my laptop I use a free account at Typhoonbackup to back up my files.

    Comment by Online Backup Service — 18 February 2010 @ 5:30 am

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