Samsung added Multi window and multi tasking capabilities to Android OS with the recent Jellybean update. Basically, Android on Galaxy Note 10.1 devices with this update will be able to behave like traditional oses, like MS Windows, or Linux (and variants) as how they can manage multiple windows, and multitask.
Samsung did a few modifications to Android, through their proprietary ‘TouchWiz’ app, effecting the upgrade. Basically constituting a framework, this allows apps which are configured for this to be able to work in multi-windows, and also be multi-taskable. Currently number of multi-window enabled apps are small, but they will probably grow. Currently browser, calculator, calendar, alarm, youtube and similar common apps are multi-taskable.
You can read more details on multi-taskable Android in Informationweek.
