System Requirements for Studying Japanese with SuperMemo
Unfortunately, SuperMemo only runs on Windows. There are no plans for Mac or Linux versions.
However, Mac and Linux users are not out of luck. Intel Mac users can install VMWare Fusion to run SuperMemo from within Mac OS X, or use Leopard's Boot Camp feature. Linux users can use WINE (I have heard good things about its ability to use SuperMemo but I have not used it myself).
To use Japanese in SuperMemo, you will need to purchase SuperMemo 2006. Although this is the most expensive version, it is also the only one that can do Japanese properly.
SuperMemo does not require much disk space and should run fine on any well-maintained computer built in the last ten years.