Abstract: Fundamental software acts as the vital link between hardware platform and software application. It is essential for building computing architectures and sustaining a strong technology ecosystem. This paper firstly reviews the history of fundamental software, explains how its technical architecture has expanded and evolved into platform-based model, and traces its business evolution from a simple hardware accessory to the central core of the ecosystem. Information technology is now entering a four-element integrated space that combines the physical world, the virtual world, human society, and intelligent machines. In this new trend, the paper delves into the paradigm restructuring that the new generation of fundamental  software platforms faces in terms of software form, system architecture, human-computer interaction, and engineering methods. Furthermore, it analyzes the key technical challenges that intelligent operating systems encounter in open environments when addressing real-time tasks, exceptional resilience, continuous evolution, and physical security. Finally, the paper discusses a novel intelligent fundamental  software stack jointly constituted by intelligent operating systems and intelligent compilers, the Internet of intelligent agents, compilation optimization, and intelligent development environments, fundamental  models and world models, and causal data lake.

Key words: fundamental software, operating system, artificial intelligence, four-element integration