Ken Kutaragi has confirmed that the HDD peripheral will be required and he encourages developers to make as much use of it as possible. It will be approximately 60 gigabytes in size and come pre-installed with the Linux operating system. Another cited feature is the ability to use the Playstation 3 HDD as a media storage device, a sort of hub from which information can be accessed through a home network. At the time of this post, it is unknown whether or not the HDD will actually be included with the system, though a
on Sony's website does say that the PS3 features a 2.5" detachable HDD slot, meaning that either it could be separate from the main package, there will be more one than one version of the PS3, or that several sizes of HDDs may everntually become available.