The “V” in ITOS-4(V) stood for “versatile.” Two characteristic functions of ITOS-4(V) were the ITOS-RDB database function and the ITOS/NET network function. The operating system was shipped with NEC System 100/58, 150/68, and 150/78 office computers. NEC developed the ITOS-RDB relational database engine for ITOS-4(V) to replace the conventional method of multiple index files. As far as end-user functions were concerned, the operating system came with RDB/EUF (also called RDBQ), which primarily provided search functionality, and RDB-MERIT (MERIT being an acronym for “manager’s easy reporting interactive tools”), which made it possible to create simple reports with RDB data. ITOS-RDB could handle standard tables and view tables (query views and join views).
As the “versatile” in the operating system’s name suggested, office computer operating systems were being used for many more business processes than just mission critical tasks. And office automation processes were at the forefront of these office computer applications.
As office automation became more widespread, NEC offered a variety of office automation software to support business decision making. These included LANFILE (data creation and search), LANPLAN (a spreadsheet function), LANSTAT (a statistics and analysis package), LANFORECAST (a forecasting package), LANMAP (a map and graphing package), LANDESK (which combined word, plan, graph, and file functions), and LANPHONE, which permitted the construction of voice-activated systems for data entry, call centers, and reservations using telephone lines connected to VS-3300 or SR-2500 voice response units. All of these programs ran locally on the terminal side and shared/exchanged data with the office computer, which acted as a server.
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. To this end, ITOS-4(V) supported up to 56 connected terminals.

Cover of the NEC ITOS-4(V) database manualCover of the NEC ITOS-4(V) RDB/EUF manual