- Software for first-generation office computers(beginning in 1973)
NEC’s first generation of office computers began with the NEAC System 100, which was announced in August 1973 and started shipping in October 1973. The NEAC System 100 predated office computers that came with full-fledged operating systems. Most office computers at this time used magnetic cassette tape as their main storage device, and they were used primarily for business processes like data entry and billing. Rather sophisticated programs for business processes could be created using simple COBOL-like programming languages, although these programs were limited in terms of available memory and peripheral devices. Operating systems would not appear until physical memory sizes increased and disks began being used as main storage devices. Most of the first office computers could only process a single job at a time. But in the three years after the first generation of office computers, CPU performance had improved to the point where multiple business processes could be executed simultaneously on one machine, physical memory sizes had increased, and disks had become available for storage. At this point, the future form of operating systems came into sight.
For its multiwork system that it began selling in December 1977, NEC introduced the OS-4 operating system, which permitted connections to up to eight stations (either typewriter stations or display stations) and could simultaneously process as many as nine tasks, including up to eight foreground tasks, such as billing, along with one batch process task. Because memory was very expensive at the time, most programs were executed in a small amount of physical memory using a Roll out/Roll in topology whereby the executing program was shuttled between main memory and disk storage. NEC would continue to apply the technology used to build this multiwork system in its next generation of ITOS office computer operating systems.
- ITOS(beginning in 1978)
- True office computer operating systems arrived with the provision of ITOS in 1978. This was a completely new interactive operating system based on an “interactive tutorial” format. The operating system relied on a keyboard and a CRT display instead of the typewriter-like console that had been the primary means of issuing command sequences to the computer. With the new interactive tutorial concept, the computer could display operating instructions to the operator, thereby greatly improving operability. In February 1980, NEC improved the overall Japanese language functionality of the operating system. ITOS became an office computer operating system that covered a wide range of systems, from small systems (standalone systems) to mid-sized systems (systems with as many as 32 terminals), because the entire family had identical software systems.
- ITOS-４(V)(beginning in 1984)
- The ITOS-4(V) arrived as an operating system with relational database functionality, called ITOS-RDB. The operating system came with functions that used relational databases as core data and with end-user database functions known as RDB/EUF．
ITOS/NET connected multiple office computers residing in physically separate offices and stores with communication lines to facilitate bidirectional access with other systems and files. This was a transition period in how office computers were used, moving from specific office tasks, like billing processes, to comprehensive jobs on a company-wide scale. Product names, too, were changing from office computers to office processors, in keeping with the trend toward integrated office automation.
- ITOS-VX(beginning in 1987)
- ITOS-VX was shipped as an operating system that could maintain the consistency of programs from standalone office computers to large systems. It was shipped alongside the new NEC System 3100 series of office computers, which were fitted with multiple processors for large system support and dramatically improved performance. In December 1988, NEC improved the PC-RDB server, a function that provided data accessibility between office computers and client computers, and in October of the same year, it offered improved network functionality.
The provision of the Aladdin integrated office system led to the development of computing environments where many different kinds of office tasks could be performed.
- A-VX(beginning in 1990)
- A-VX was an advanced operating system with greater system performance than ITOS-VX and offered scalability for even larger systems. The LAN Manager server function (LM/A-VX) gave the operating system the ability to link with LAN Manager, which was the de facto standard network operating system. Flexible systems could be built in combination with other personal computer integration software. This LAN Manager server function eventually became the technical basis for the later A-VX III operating system, which ran on Windows.
- A-VX II(beginning in 1993)
- A-VX II was the operating system for NEC’s 7200 series of office server systems, which offered a much-improved cost-performance ratio.
At this time, the overall performance of systems was advancing rapidly and customers were calling for ever-larger systems to be built. In response, NEC rolled out 16 models, ranging from the 7100 series of standalone office server systems to its flagship model, which could be scaled up to support as many as 2,400 connected terminals. Reliability was improved with the use of disk array units and the provision of hot-standby functions. And in pursuit of greater application productivity, NEC provided SEA/I, a software development assistant system, and SOFPIA and IDL Tool as software development assistant systems that operated in client-server configurations.
- A-VX support for open platforms (beginning in 1995)
- From this point on, A-VX versions were provided as operating systems that ran on Windows, an open platform. This allowed A-VX software to link and work together with the many open-platform software titles for the construction of an even wider variety of systems.
- A-VX III(beginning in 1995)
- As open-platform operating systems (UNIX and Windows) grew in popularity, A-VX III included functionality so it could work in conjunction with these open-platform operating systems to implement various systems that could not be implemented strictly with an office computer operating system alone. A-VX III also made it possible to continue using user assets from office servers (System 7200 series) and to work in conjunction with Windows NT application software.
- A-VX IV(beginning in 1997)
- A-VX IV was introduced as an operating system that maintained the continuity of office server assets (System 7200 series) and that could work in conjunction with Windows NT application software. In November 1998, NEC beefed up its Database Replicator function, which created duplicates of office server relational databases in Windows open-platform databases (Oracle or SQL servers). In July 2000, NEC added more functionality to its Open Database Access kit, which allowed legacy applications to directly access Windows open-platform databases (Oracle or SQL servers).