An embedded system is a specialized computer system that is application-centered, customized to fit special hardware, designed to satisfy some special requirements of functions, reliability, size costs, power-consumption, and so on. In this research, we create an embedded spatial database (or called geographic information system (GIS)). To perform non-trivial tasks, an embedded system usually is consisted of two integrated components: a customized operating system and an application system. In this research, we modify an existing operating system (Linux) to meet the special requirements for supporting a spatial database, and create a spatial database on the operating system. Since the operating system is required to support a single application, we have the freedom to build a customized file system in order that the requirements of high performance and small size can be achieved. In building the file system, we develop new technique for physical block allocation, data buffering, and reducing system overhead.