If you are doing a large number of SuperMemo repetitions, you should back up your data every time you finish. The easiest way to do this is to choose File: Copy Collection and then make a backup. You don't have to make a new backup each time; you can overwrite an old backup.

But backing up on one computer isn't enough-- what if your hard drive dies? If you plan on using SuperMemo to become fluent in Japanese, you will end up with months and years of data. Losing it all is almost unthinkable-- so take the steps to make sure you don't have to deal with it.

One easy way to handle the backup is to backup your collection to CD or DVD. This is generally sufficient, but if you're going to back up, say, every week, you'll burn a lot of media that way.

Personally, I back up to the Internet using Mozy. Mozy is a service that makes money by selling people unlimited backup for $5/month. However, they will offer you a free 2GB account to try to entice you to use the service. 2GB is plenty to backup SuperMemo collections, so it's a great solution. The only problem is that once your SuperMemo collect includes thousands of files (and it will, since it makes a few files for each item in your collection), Mozy takes forever. But there is a simple solution to this: just zip the files.

Here's a step-by-step guide if you're having trouble following:

• register for Mozy
• backup your SuperMemo collection
• repair your SuperMemo collection
• open My Computer and go to C:\Program Files\SuperMemo\systems
• Right-click on the folder named for your collection and choose "Compress Folder"
• copy this compressed folder and your my_collection_name.kno file (in the systems folder) to a folder that Mozy will back up
• press "Start backup" on Mozy

SuperMemo Official Guides

• SuperMemo Backup Guide
• SuperMemo Backup FAQ