Nanocomputer

Nanocomputing technology is the apogee of bioelectronics and miniaturization. A nanocomputer is an tiny photonic computer that is commonly inserted on the occipital lobe of the user and used a bioelectric interface to link with the user's brain.
Commonly, a nanocomputer is installed during birth in most of the inhabitants of the core worlds. a nanocomputer has a small capacity compared to other storage devices but it can easily interface with any storage links to the neural network of the user. Most nanocomputers are issued by the USSA but the parents can opt-out and have a specialised or higher quality chipset installed into their child.
Nanocomputers can be replaced. Most people replace them once or twice in their lifetime. Scientists, Programmers, hackers, technology enthusiasts and military personnel are known to replace them almost everytime a better version comes out.

Utility

Nanocomputers are needed for most of daily life in the core worlds. Digital wallets, entertainment, access and authentication are all handled by a nanocomputer. In more advanced versions, nanocomputers are used to interface with Gridcasters, Gridsuits or other types of specialised equipment like Power Armours, spaceships or other vessels.

Access & Availability

Everyone in the core worlds has access to the USSA standard issue nanocomputers.
Residents of the Inner Rim and Outer Rim have to buy them but they are not hard to find. In most cases the difficult part is to find someone to install it safely.
Military personnel and corporate staff of Megacorporations get specialised versions from their respective organizations depending on the tasks they perform.

Discovery

Nanocomputers are the result of amazing breakthroughs in many sciences like bioengineering, computing and electronics miniaturization. It was not so much a discovery but a slow steady and natural progression.