In a later interview with TabTimes, Kay said personal computers should be designed like an architect designs a house, as a place where people are going to spend a lot of time and different people can exist there.
Regarding the "different people can exist there", he is right about that. The iPad should allow multiple users to use it better, but that creates some unique challenges too.
Because most owners of an iPad spend a lot of time on the device, it allows little room for others to use it. Most people who I know, with an iPad, have trouble sharing it. The second person end up having to get their own iPad.
One challenge is storage. Except for the new 128GB iPad, most people don't have enough storage to allow every user to store their photos, music or movies.
The software would have to work like the match service that Apple runs. If while on my profile, I attempt to download a song to the storage that already exists on another profile, the OS would have to know that and know not to add the song again, but rather allow me access to the existing song. If one of us deletes the song, it would need to stay available for the other user(s). This would have to be done for other types of storage hogs like movies, videos, photo and even apps.
Some apps like Plants and Zombies allow multiple users to have and maintain their own stats, but it does not prevent the other users' info from being accessed or altered. In a multiuser tablet environment, the OS would have to provide protection of user data.
Then you would have to have superusers. What if it was my iPad, but my kids have all of the storage used up with their junk. Should I be able to delete some to regain space? Are tablet makers wrong or have they simple recreated the "personal computer" where is is not personal because you can personalize it, but rather because it is truly a "personal" device intended to be used personally by one person?
Carl W. Brooks