macbookpro

The macbookpro was introduced 2006 amd replaced the powerbook G4 with an intel proecessor and with 13- and 15-inch screens. A 17-inch version was available in the first and second generation, but not in the third.

The first generation macbookpro appeared externally similar to the powerbook G4, but used the intel core processors instead of powerpc G4 chips. 

The macbookpro second generation, known as the "unibody" model, has a more tapered design and a casing made from a single block of aluminum.

The most substantial differences in the third generation macbookpro are the fitting of a significantly higher resolution retina display, the elimination of the optical drive, and replacement of hard disk drives with solid-state drives.

2016 Apple announced new fourth-generation 13 and 15-inch macbookpro models. The models introduce the touch bar, a multi-touch enabled oled strip built into the top of the keyboard, replacing the function keys. They also include a sapphire-glass covered touch id sensor at the right end of the touch bar. The enclosure continues to be an all-metal unibody construction with significant reduction in volume and weight. All ports have been replaced with either two or four thunderbolt 3 ports, any of which can be used for charging, and a standard 3.5mm headphone jack.

The models also introduce a "second-generation" butterfly mechanism keyboard. The fourth generation 13-inch model has a trackpad that is 46% larger than its predecessor while the 15-inch model has a trackpad twice as large as the previous iteration.

Apple also introduced a new lower-end 13-inch model which lacks the touch bar in favor of function keys and has only two Thunderbolt 3 ports.