Seamless computing refers to a potential end-state for technology. Right now there aren’t standardized APIs that can be used across every technology platform, and many solutions are naturally siloed from one another. Over time these divisions are being broken down, and technology as a whole is becoming more integrated.
Seamless computing also refers to your session state. Once technology matures and becomes integrated, you will be able to have a persistent session that links your mind with the technology across separate pieces of hardware (virtual reality, embedded technology within your body, heads up displays, etc).
Technology is progressing at a fast rate, but it is still in its infancy. Automation, machine learning/AI and infrastructure consolidation will help streamline the technology, but for now both software and hardware require a substantial amount of manual maintenance and are prone to failure.