I understand that when I press and release the power button on the top of my iPhone or iPad, it stays on but turns off the screen.
Whereas if I press and hold the power button, a "slide to turn off" control appears on the screen.
Sliding this, as I was told, does turn the unit off, but it does so by suspending the RAM to disk (flash memory, actually.) So, when turning on the iPhone or iPad, it isn't so much rebooting the OS as it is resuming it from flash storage.
How to force the OS to completely reboot on these devices?