DIPS, a series of computers and their software by Nippon Telegraph and Telephone Public Corporation (NTT, now called Nippon Telegraph and Telephone Corporation), was developed for the on-line computer systems to be used in the data communication services from the outset. The research and development of the communication management program (CMP) for DIPS was started for effective data communications between nodes (host computers and terminals) that constitute the network system. The communication management program (CMP) was developed in five phases: (1) CMP-1 and earlier, (2) CMP-2, (3) CMP-10, (4) CMP-11 and (5) CMP-12 (1988 onward).
- （１）CMP-1 and earlier
- During the era of DIPS-103OS, the communication channel management processing (e.g. connection/disconnection, assembly/disassembly of transmitted characters) was conducted by the firmware installed in the communication control equipment (CCE) for DIPS, and the transmission control processing was assigned to the main OS. With this method, however, it was necessary to rewrite the ROM (Read Only Memory) embedded in the CCE in case to support new types of terminals and the diversity of types of networks such as an digital data exchange (DDX) packet exchange network, it difficult to ensure rapid response in supporting new and various communication technologies.
Therefore, in 1972, the development of the DIPS-7300 communication control processor (CCP) was started for building the communication control dedicated processor. The character-buffer type communication prototype program was completed to ensure the same functions of CCE as the first software running on 7300 CCP in 1974, and also the development of the message-buffer type communication program at the front-end processor (FEP) was started in November 1973. The development of the message-buffer type communication program was conducted along with the 105OS development plan with the aim of providing computer communication services for DEMOS-E system.
In 1975, the FEP method was also decided to introduce into 104OS, and the research and development was started how this could be achieved. CMP-0 is the product compliant with DCNA version 0specifications, and its development was completed at the end of fiscal 1978. This product was equipped with enhanced functions such as accommodating a nonprocedural terminal in addition to the end-to-end protocol processing. CMP-1 was the product compliant with DCNA version 1 specifications, and its development was completed at the end of fiscal 1979. This product had the enhanced relayed communication supporting function in addition to accommodating the commercial packet communication services.
- In 1978, the development was started for CMP-2, the communication management program that supported the 7400 family CCP in addition to 7300 CCP for communication control processors, and supported the remote processor (RP) in addition to FEPs.
Formerly, the lower levels up to the transport layer compliant with DCNA were achieved on the CCP, while higher levels of DIPS-specific were processed on the host (logic terminal access method of 104OS). With CMP-2, it was decide to provide the DCNA specification compliant access method for higher level processing,, in order to provide the DCNA specification compliant access method for higher level programs. Subsequently, these procedures were packaged into the DCNA higher-layer protocol processing package (e.g., file transfer, message transfer, virtual terminal, database access).
The development of CMP-2 was completed at the end of 1982.
- The development of the CMP-10 was started in April 1981 with the aim of achieving the network distribution system by replacing the previous CCP (7300 CCP, 7400 family CCP) with a DIPS small processor (DIPS-V20), and was completed at the end of fiscal 1983.
With CMP-10, in order to realize the communication management functions consolidated on the host (DIPS small processor), it was necessary to improve their performance. Therefore, it was decided to improve the performance of the communication management programs through structural reorganizations such as achieving the communication control functions in the form of ICA (Integrated Communication Adapter) firmware, redesigning the module structure from by-function to by-process, and reducing interactions between the OS and the ICA.
In addition, it simplified the configurations of the network distributed system by promoting compliance with DCNA specifications such as unifying the intra-network protocols to DCNA, in virtualizing the basic communication procedural terminal at the accommodated node, and unifying higher program interfaces to DCNA by adopting the DCNA virtual terminal protocol.
- The development of the CMP-11 was started in October 1982 with the aim of accommodating with a large-scale network and diversifying the services, enhancing the functions to be sophisticated and to enable computer networks to be built economically, improving the mutual connectivity function between computers of different types, and establishing a highly reliable system, in order to strengthen market competitiveness.
The development of the CMP-11 was conducted in five steps: Releases 1, 2, 3, 4-1 and 4-2.
■ Release 1 (development started in October 1982, completed in March 1985)
Release 1 was developed with the aim of accommodating with the expansion of the scale of the network distribution system, diversifying the services and enhancing the functions for sophistication with the DIPS-V series.
The number of nodes that could be accommodated was increased to achieve a large-scale network. In addition, supporting communication procedures were extended for non-interactive communication protocol and dedicated communication protocol (e.g., J procedure, JBA [Japanese Bankers Association] protocol), and types of connectable networks were extended to the DDX circuit exchange networks and the facsimile networks.
■Release 2 (development started in June 1983, completed in March 1986)
Release 2 was developed for the DIPS-II/5E series in order to make the program applicable to the computer complex system configuration consisting of multiple hosts and FEPs, a mixed Hosts configuration with a conventional CCP (communication control processor) and a stand-alone Hosts configuration, to respond to network diversification and to establish a highly reliable system.
To respond to network diversification, functions were added such as for communicating with terminals in a LAN, for supporting communication protocol conversion and for connecting with a DDX network (1980 version X.25)
In addition, as for establishing highly reliable systems, this release realized a function for high-speed recovery and restart processing of the host/FEP with a complex configuration system, maintained communication processing so that the terminal user would not be aware of a “host down” event, and shortened the restart time in the event of FEP failure.
■ Release 3 ( development started in October 1984, completed in September 1987)
Release 3 achieved layers 3 to 5 communication processing programs in accordance with the OSI (Open Systems Interconnection) protocol, defined as an international standard, in order to allow connection with OSI protocol compliant terminal/computers. In addition, the release supported a function for directly accommodating super digital line service at line speed of max, 1.5 Mbps in order to allow an economical system to be built.
■Release 4-1 (development started in April 1986, completed in June 1988)
Release 4-1 enhanced the OSI protocol processing functions and supported a TCP/IP protocol via LAN in order to improve the connectivity between different types of hosts /terminals. In addition, it also supported vendor-specific communication procedures for consolidated RC to expand the scope of connectable terminals of other vendors.
■Release 4-2 (development started in June 1987, completed in December 1989)
Release 4-2 supported a function for directly connecting to ISN Net 64/1500. Additionally, it supported a function for directly accommodating 6 Mbps super digital circuit for establishing an economical network.
It also realized a gateway function that enabled multiple DCNA networks of different addressing coordinate to be connected with each other so that an existing network could be utilized as-is to allow easy expansion of networks, in order to establish a large-scale network using an existing network.
The whole development of the CMP-11 series was completed at the end of fiscal 1989.
- The development of the CMP-12was conducted in three steps: Releases 1, 2 and 3, starting October 1988, with the aims of further strengthening the DIPS communication management functions to respond to greater technical sophistication, broader areas and the multi-vendor trend of communication systems, improving operability and enhancing the function for long-term maintenance and management.
■Release 1 (development started in October 1988, completed in December 1990)
Release 1 supported communication with the H channel (384 Kbps) and the D channel of INS (Information Network System) Net, version 2 protocol on the session layer of OSI, and achievement of 40 digits of network addressing in preparation for the spread of large-scale networks.
In addition, it simplified the operations for system generation, testing and running, and facilitated the modification/collection of system information.
■Release 2 (development started in October 1989, completed in April 1992)
Release 2 achieved the communication procedures based on the latest INTAP (Interoperability Technology Association for Information Processing, Japan) l and the MEA (Message Enabled Application) specifications in line with the trend. Additionally, it added a function for TCP/IP-based protocol processing. It also simplified the SG (System Generation) procedures by enabling to add terminals without detailed registrations in order to respond to growing scales of networks and frequent network configuration changes.
Moreover, it increased the system reliability through strengthening the guard and enhancing the quality assurance test, for the software and system, and realized a function for efficient gathering of information about events of the system, in order for the effective trouble shootings in the long-term maintenance management operation.
■Release 3 (development started in April 1991, completed in April 1993)
The development of the release 3 was conducted focusing on improvement of operability and enhancement of the maintenance of the system, communication connectivity between machines of different types, and efficiency in maintenance and management of the system.