A demonstration of the new MacBook Air and MacBook Pro systems was one of the key components of the company's WWDC keynote address on Monday; with the highlights being the streamlined I/O offerings of the two devices as well as their discontinuation of optical drives.

In order to ensure that some space is saved in the systems, Apple has introduced a combination of USB 2.0 and 3.0 connections; and has also brought on the I/O connectivity from older Mac systems, largely by depending on its Thunderbolt connections.

The evolution of the MacBook lineup over the years has already resulted in the systems being gotten rid of legacy ports, including MacBooks Air system's Ethernet port; as well as FireWire from a few MacBook systems, and the ExpressCard slot from all MacBook systems except the company's 17-inch MacBook Pro.

The move has largely been an upshot of the inclusion of Thunderbolt in the MacBook systems, particularly because Thunderbolt enables the users to add any I/O technology that they require. At present, both Apple's Thunderbolt Display and forthcoming third-party docking stations offer the mentioned advantage, though they are comparatively more high-priced offerings which may also likely include certain features - like a display - which may not be needed by the users.

Going by the announcements marking Apple's keynote, the built-in connectivity options in the Apple laptops will no longer include Ethernet, FireWire, or ExpressCard; though the company will sell Ethernet and FireWire Thunderbolt adapters at a cost of $29 each.