【NTT】 DIPS-104-01OS

The development project of DIPS-104OS was planned in order to expand the fields of deployment for DIPS in the data communication market, taking into account subsequent technological trends and business trends, where competition among system vendors was intensifying. Based on the experiences of developing DIPS-103-10/11OS for a time-sharing system (TSS) and DIPS-103-20/21OS for a real-time system (RTS), it was required that the cost-performance ratio and reliability throughout developments of various new technologies, including the multi-processor control method, in addition to improvements of existing technologies, be increased.

At that time, in terms of hardware, the transition from the DIPS-1 to the DIPS-11/10 series was underway. Respective achievements in pursuit of technologies for increasing speed, capacity, and reliability, reducing size and cost, and making the system more flexible both for the main system and for peripherals, were accomplished.

With regard to the OS for DIPS, 103OS was released and introduced into commercial systems. Initially, 103OS for duplex-system operation was released, and then the development was divided into two families: 103-10OS series dedicated to TSS and 103-20OS series dedicated to RTS. Those two OSs were put into commercial use. In December 1973, the 103-10OS was introduced into the scientific and engineering computing system DEMOS-E. The 103-20OS was introduced into the sales/inventory management service DRESS in October 1975 and then into some banking service systems.

During that period, OS-related technologies made significant advances in processing, such as multi-processor (MP) control, virtual storage management, and communication control, in response to increasing diversification and sophistication of the fields in which computerization was being applied. Meanwhile, it became necessary for the data communication service of Nippon Telegraph and Telephone Public Corporation to address public, nationwide, and technology-led national projects as well as to enhance the quality of existing services. Accordingly, there arose a need to develop a new OS that would be highly marketable, ensure a high cost-performance ratio, and be highly applicable to various RTSs, including those of national projects, by introducing new methods/technologies to OSs in addition to developing improved hardware enhancing the DIPS-11/10 series.

In the DIPS project, MP processing was planned as a major technological feature from the outset. However, technologies supporting MP processing were premature, and there was no opportunity to realize this feature with the 103 family OS. Despite this, with the advance of technology and the rise of market demand, the ECL decided to develop 104OS as a new OS supporting MP processing.

In late 1971, with the development of the 103OS family on track, the ECL started work toward the development of 104OS for MP processing and multi-service processing support. However, for multi-service processing, it was difficult to set the requirements concerning the operational conditions for the system at the computer-host center before the applications and the services had been determined, and the plan coincided with the busiest period of the efforts to develop the 103OS family. Therefore, the study was temporarily suspended.

In 1973, the ECL had prospects for resolving the technological challenge concerning MP control and set the requirements by limiting the new OS to apply to RTS only. In 1974, the ECL started full-scale development of the 104OS. The 104OS was released in a series of steps, from Release 1 to Release 3. Release 1 was launched in mid-1976, Release 2 in mid-1977, and Release 3 in 1978. The functions developed with this OS were long used as the base functions of following DIPS-OS development.