Technology is evolving so rapidly that even the one “license per computer” dogma is being challenged. Dual Core Processors and the forthcoming era of virtualisation mean that one physical machine may contain two or more virtual machines – a little like virtual desktops.
Each of these virtual machines would be able to work on their own, independent from one another. It would, therefore, be possible for the average user to have a “work” configuration, a “game” configuration and a “testing” configuration etc, the important bit being that whatever might go wrong to one virtual environment has no impact on the other ones.
Open source software is not affected by licenses as it is basically an “install as much as you can” policy. As for commercial and proprietary software (CPS), various software vendors have different policies when it comes to licenses. Microsoft, for example, stipulates that you can install Office on up to two computers (desktop and laptop), provided the two are being used exclusively by one person only. That’s valid for the shrink wrap version.
The educational version can be installed on up to three computers, whilst the OEM one – which comes with your computer on purchase, can only be installed on only one.
Other vendors, including Sun Microsystems and IBM may license software to you per core, per seat or per user. Speaking of Microsoft, its open discount scheme on their popular software packages might be of some interest to you.
You can read about the ten other myths of commercial and proprietary software here.