The original Raspberry Pi was a new and innovative device with great potential. It was massively successful after its release and was used for a vastly greater number of projects than was predicted. Unfortunately the device had some minor drawbacks that other, competition devices, did not. The power management on board was not very efficient and could not provide much power to USB devices. It was limited to two USB ports and high powered devices required a dedicated power source or a powered USB hub. The bad power management also meant that hot swapping devices caused a system reboot to occur (biglesp, 2014). This has been fixed with a better power management system, allowing devices to be powered by the board fixing the hot swapping problems and the 2 USB ports have also been upgraded to four.
Another limitation to the device was its number of General Purpose Input/Output pins. Competition devices such as the Beagle Bone Black have a vastly higher number of GPIO pins giving them an advantage here. The number of GPIO pins has therefore been increased to 40 allowing better connectivity and expandability. This also creates starts to close the bridge with the Pi Compute model’s 120 GPIO pins.
The SD card slot has been removed in favour of the smaller micro-SD version, and the two composite video and audio ports have been replaced by a single port (BBC, 2014).
The board still uses the same Broadcom chip and ram and still includes the same display and camera ports as previous boards. The board overall is slightly smaller and the layout has been modified to cater for the improved features. Even with these modifications and upgrades the B+ model is still only £20.
BBC, 2014. News: Technology: Redesign for barebones Raspberry Pi computer.