The development of the DIPS-103 Operating System as the standard OS proceeded through the inclusion of technological breakthroughs, such as virtual memory space management, a VMAP file access method that did not depend on the physical properties of the storage equipment, and a VFS file recovery method that used a virtual file for a time- sharing system (TSS).
In the process of the project, it was clear that the TSS would be achieved, with slight improvements on the DIPS 103OS original functions, by supporting the DEMOS-E system specific commands. However, for a real-time system (RTS), it was found that measures such as drastically redesigning the file system and the execution management system of the 103OS would be necessary.
Therefore, the project was divided into two development streams: tuning up 103-10OS for TSSs and tuning up 103-20OS for RTSs.
The 103-10OS for a TSS was commercially introduced in 1972 into the TSS service (DEMOS-E service started in November 1972) systems of the Nippon Telegraph and Telephone Public Corporation (now called Nippon Telegraph and Telephone Corporation). Subsequently, the TSS functions of the OS were continuously improved to support communication functions between computers; it evolved into 105OS.
The 103-20OS for an RTS was developed by improving the control program of 103-10OS and packaging the real-time specific functions, including private file support functions using the conventional Volume Table of Contents (VTOC) method.