As first noticed by Jim Dalrymple at The Loop, the switch, located just above the volume controls on the right side of the device, is now devoted to locking the screen orientation in its current state. Previously, the switch was used to mute the iPad.
One of the features Apple has touted with the iPad is that it can be used from any orientation the user sees fit. The new feature will prevent users from having the screen rotate unexpectedly as they use the device while browsing the Web, reading an e-book, or accomplishing any other task on the 9.7-inch screen.
"There isn't even a single orientation," Jony Ive, senior vice president of design with Apple, said in the iPad's initial promotional video. "There's no up, there's no down, there's no right or wrong way of holding it. I don't have to change myself to fit the product. It fits me."
Like with the iPhone and iPod touch, the internal accelerometer of the iPad automatically adjusts the display to fit the orientation by which the user is holding the device. The iPad allows even more functionality than with the previous products, granting users the ability to turn the iPad completely upside down, with the home button up top, if they so choose.
Because the iPad has a focus on reading e-books and newspapers, many users will undoubtedly use the device as they would a physical book or newspaper -- objects that are sometimes read by users laying on their side. The screen rotation lock would prevent the device from shifting as a user moves around.
Additional physical inputs on the device are the on/off and sleep/wake button, volume up/down controls, and the home button.
Apple began accepting preorders for the iPad Friday morning. Purchases for the device, scheduled to ship April 3 for the Wi-Fi-only model, are limited to two per customer.