The OKITAC System 9 was developed to be a force in data processing based on the following principles.
- Better operability on both the hardware and software side
- Enhanced reliability and maintenance functions
- Easy construction of multiwork systems
- Full Japanese language processing functions and graphics processing functions
- Simplified AP development
- Continuity for past software assets
- Software compatibility among all models
CROS (which stood for conversation real-time oriented system) was the operating system for this new OKITAC System 9 series. CROS/D used hard disks as its storage media, whereas CROS/F used floppy disks. Both were real-time multipurpose operating systems with functionality for both operating applications and developing programs.
- The features of CROS were as follows.
- ・High-speed real-time operating systems
- The operating systems offered enhanced real-time performance with up to 250 levels of priority control, controls and functions to execute as many as 250 simultaneous tasks, and timer, external interrupt, and other event handling functions.
- ・Improved man-machine interface
- Not only could the programs needed for program development be operated interactively, there was a function for calling as one command a group of commands stored in a file as an alternative to entering operator commands from a terminal.
- ・Multiwork systems
- To provide a more enriched multiwork environment, the operating systems came with multi-terminal control functions, so that multiple users (operators) could work simultaneously on program development or program execution, and functions to verify system usage privileges and file access privileges.
- ・File operations
- The operating systems provided four file access methods — sequential, direct, distributed sequential, and indexed — for effective, flexible support of business process applications without requiring extensive hardware knowledge.
- ・Japanese language processing
- The operating systems came with several programs and dictionaries to support Japanese language processing functions. Japanese was also used for system messages, and COBOL and BPL permitted definitions and input/output of Japanese language data.
- ・Database management system
- In consideration of constructing highly efficient data processing systems, the database management system kept data definitions and reads and writes separate from programs as a way of simplifying updates and extensions.
- ・Better reliability
- The operating systems came with a file restore function, a retry function for input and output devices, and fault troubleshooting and preventative maintenance functions, such as logs, to improve overall system reliability.