Shareware Beach

Tuesday, 27 February 2007

The Value of OS Disk Images

Filed under: Software Development — Jan @ 13:56

Whenever I get a new computer, the first thing I do is to repartition the hard disk, so I can have a separate partition for the OS and applications, and another for all my data files. In fact, I have multiple OS partitions so I can boot multiple versions of Windows, but that doesn’t matter for today’s topic.

The key benefit of the separate OS partition is that I can easily make a backup of the whole system by making an image of the partition. Personally I use Paragon Drive Backup for this. Norton Ghost is another popular hard disk backup utility. The real benefit is that I can restore the OS partition to a known good state in about 10 minutes.

Every time my system is working fine, I make an image of the OS partition. Usually I do that a few days after installing something new, when I’m sure all went well. I save the last backup on the data partition. I also burn the backup to a DVD-R. I keep all the backup DVDs for the life of the PC, so I can go back to a previous installation if I have to. Restoring the backup only takes about 10 minutes when using the image on the data partition as the source. Restoring from DVD takes longer.

I’m still surprised that many shareware industry professionals don’t have a solid backup strategy. Take Dave Collins. In the latest issue of his Competitive Edge newsletter, he recants how he wasted 8 hours reconfiguring his system after an Office 2007 installation went awry. With proper backup procedures, he would only have to waste a few minutes to start the restore process, which could then run unattended for the next 10 minutes or so.

In fact, with a proper backup system in place, you don’t have to be afraid of messing up your system. I don’t use any anti-virus or anti-spyware software. If my system starts acting up, I’ll restore the backup, and have a guaranteed clean system. No spyware remover can beat that. If I want to play with beta software, I don’t have to inconvenience myself by running it in a virtual machine. I do use VMware for testing my applications on clean installs of Windows. But when beta testing new versions of tools I use for development, I want to test them in my actual development environment rather. When the beta expires, I wipe it off by restoring the OS backup.

My data files remain untouched during all this. For those I have a separate backup strategy, which involves keeping them synchronized with a backup computer (my laptop) and keeping rotating backups on DVD+RW discs.


  1. I like your strategy. How do you deal with the fact that a clean install of Windows always creates the “My Documents” folder for each user under the OS drive’s (C:)\Documents and Settings? How do you make sure that all the per-user data (registry, profile) makes it onto your second partition/drive and how do you restore that information, should you ever need to do a clean install of Windows? How does this change for Windows Vista?

    Comment by GeekTieGuy — Friday, 2 March 2007 @ 13:03

  2. I do this for fresh installs of a new PC once I have all service packs and divers up to date and installed the main apps (Office, common tools etc). I use Acronis True Image (the best drive imaging tool at present).

    Some gotchas to using drive images:
    - Once you start installing many apps the image becomes huge. Fine to backup on another partition but not reasonable to burn to DVD+/-R (at least not frequently). My current system drive (which contains the OS and installed apps, My Documents – I don’t put much there – application data files and so on but no games or other bloatware) is 55GB uncompressed. This might come down to 20-30 GB in a compressed image but that’s at least 5 DVD’s. It might fit on a single HD-DVD or Bluray disk but the drive and the blanks are still too expensive.
    - You can’t expect an image to work on a different PC. If the hardware (mostly motherboard and GPU) is similar you might get away with it but expect a manual reinstall on upgrading your PC.


    Comment by Alfred — Thursday, 1 November 2007 @ 9:18

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