Misinformation about iPod patent

There has been a lot of publicity recently on a Microsoft patent by someone named John Platt which seems to cover the iPod interface. Some of the "pundits" are misstating some of the legalities, so I thought I'd say something about that here. For instance, PC Pro says:

Apple invented and publicly released the iPod interface before the Microsoft patent application was filed,' a company statement reads.

Under US law, you cannot patent something than someone else has already made. In theory this invalidates Platt's patent.

The writer's assertion is not true. The fact that Apple invented and publicly released the iPod interface before the patent application was filed does not necessarily mean the patent is invalid. In the U.S., the real issue is the date of invention.

It is conceivable that Platt can prove that he invented the user interface before Apple did, giving Microsoft the rights to the patent.

However, that does seem unlikely in this case, since it does take quite some time to actually build a device like the iPod, and much less time to file a patent application.