Hardware
Imagine a block the size of a PC card. The block would contain the operating system, all of the enhancements to the operating system and all of the documents, music, images and other data files. It would also contain a set of smart batteries. Whatever other device the block was connected to would contain a CPU, display, input devices, modem, networking devices, optical drives etc. The hardware would also have firmware to match the operating system to its display type and input method.
So the block would be the heart of the system. The block would be "Me." The block is also the switch to turn on the other devices. Insert the block into the faceplate of the desktop device and the desktop device turns on. The desktop charges the block's smart batteries while you check your email and update your pages.
You pull the block from the desktop, turning the desktop off and insert it into your combination phone and PDA. The display automatically adapts to the PDA screen size and pen input. Once in your car you slot the PDA into its cradle and the car tops up the battery. The car stereo now adds the music in the block to its playlist. A call comes in and its routed through the stereo as well.
At work you plug the block into your wifi tablet. When you checked your mail at home the desktop dialed up, in the car the cellular phone dialed up, now at work the tablet fetches mail from the company server. The block knows where it is by what its plugged into, you don't
have to do anything. Meanwhile back at home your son plugs his block into the desktop. Nothing that you did remains on the desktop so there's no way your son can damage your operating system or data.
On the PDA or tablet there would be an eight way centred joystick under your left thumb. Pressing the joystick would step the focus through the four permanent panels of the interface. Pressing and holding would step the focused panel through normal, larger and full screen. Nudging the joystick left or right would tab through items or options in the panel and nudging up or down would either scroll through the view of a panel or change the value of tabbed options.
On the desktop the screen edges could be activated to replicate the joystick; slamming the pointer against any edge would simulate nudging the joystick and a mouse button under the thumb would simulate pressing the joystick. Screen corners could be used for quick jumping. An open document could be slammed top left for later reading; an item or clip could be slammed top right to the temporary stash; contacts could be slammed bottom left to add to the speed dialling list; bottom right could be a screensaver or hardware status display.