With the progress of information-oriented society, many device with advanced technologies invented by many companies. However, the current firmware technologies have many problems to meet such high level of new Technologies, Recently it become necessary new manufactures of information-oriented society to require such embedded operating system as their system-level platform. Embedded linux, which could be on alternative proposal of existing high-cost embedded operating system, become available commercially by many companies Linux has many programs, But, embedded databases require very high cost. In this paper, we suggest ERT DE which has a small size and is suitable for embedded real-time technologies.