I would like to understand why they are using helium at all instead of a several other plausible alternatives. The article offers the following rationale for using helium in this capacity;

>>>At one-seventh the density of air, helium produces less drag on the moving components of a drive - the spinning disk platters and actuator arms -- which translates into less friction and lower operating temperatures.<<<

This appears to be a slight misunderstanding as the density of any gas is variable and we have found that it is directly proportional to the unit weight of the substance, the pressure and inversely proportional to temperature. It is not fixed. They could have easily achieved the result in multiple ways. For instance, to reduce density it might have been easier to simply reduce pressure and then create a hermetically sealed chamber with a reasonably inert gas with low atomic or molecular mass such as nitrogen. This should have saved them a lot of trouble as helium is actually pretty hard to contain. An alternative nitrogen based solution would also have been good enough for a long enough period of time and it could have been achieved in a much less expensive manner. (they say in the article that successfully trapping helium for a long enough period of time required a decade of research. This is a relatively solved problem for gases such as nitrogen)

I am sure that the people at Western Digital can see something that I don't - I'm just curious as to what that insight is. What makes helium worth all of the trouble?