From the birth of the first mobile phone, we have been used to regard it as a single object. It was possible to replace the battery with a higher capacity model, expand the internal memory with a microSD card and little else.
Over the years, manufacturers have tried to add external modules to increase the capabilities of mobile phones. We remember, for example, the external camera for the Sony Ericsson T68i, or more recently the various add-on modules available for Iphone.
Since the dawn of modern technology, personal computers have always had a modular architecture. The desktop PC and, in a lesser way, notebooks have always been built with replaceable components (Cpu, Ram, video card, hard drives) so it’s possible to customize their configuration and upgrade over time. All this implies a standardization in personal computers, with reference to the connection interfaces, such as Pci Express for video cards or Sata for hard disk drives. Interfaces are difficult to miniaturize and implement in smaller devices. This explains why in the notebook, expansion opportunities are limited and some components, like the Cpu, are welded and non-replaceable.
Until now, think of a mobile modular phone was considered science fiction. Modern smartphones were too small for the integration of connection interfaces and separate modules. The weight and size would have been excessive. All this was true until the arrival of the Motorola / Google with Project Ara and Phoneblocks, which will be discussed separately.