【Hitachi】 OS7

OS7, which Hitachi developed as the OS for HITAC 8700/8800, was a large-scale software system that supported a virtual space and multiple processors. At that time, its scale ranked at highest level in the world.

 Hitachi announced OS7 in November 1970, and started shipping it in October 1972.

 OS7 had the following features:

Feature Description
Adoption of virtual storage The OS allows the user to use a large address space and create a program beyond the framework of the conventional overlay structure. In addition, a swapping mechanism using a high-speed magnetic drum is adopted in order to achieve a large virtual space on the core storage.
Support for interactive processing and remote batch processing The center can simultaneously open up interactive processing and remote batch processing to the user, in addition to batch processing and the real-time processing. In addition, because programs, commands and user files are configured under the same system, extensive flexibility is ensured, such as use of the results of batch processing in interactive processing.
Increased availability The OS supports multi-processor and duplex configurations, and means to cope with faults are taken into account.
Function for managing jobs and files The OS encourages laborsaving in center operation through job stacking, efficient scheduling, control of effective system resource use, and reduction in the operator’s workload.
In addition, it provides various methods for accessing files to achieve simplified handling of files, as well as a catalog function.
It is also equipped with security mechanisms such as storage protection at the ring level.
Powerful language processor system Provides a FORTRAN compiler with an advanced optimization function, PL/I, COBOL, assembler, interactive language BASIC and a FORTRAN syntax checker.
Easy-to-use utility programs Equipped with utility programs such as a linkage editor, a sort/merge program, a program for maintaining libraries, a program for maintaining files, a program for maintaining volumes, a program for debugging support and a test data generator.
Allows the user to also handle these as batch jobs in commands of the same system from a terminal, increasing processing efficiency.

 Figure 1 shows the software configuration for OS7.

Figure 1 shows the software configuration for OS7.

Figure 1 shows the software configuration for OS7.

  In January 1973, a joint-use system based on the HITAC 8700/8800 system, with OS7 installed, started operating at the Computer Centre of the University of Tokyo. At that time, reception of jobs and return of job results in center operations were normally performed with human intervention. However, the Computer Centre of the University of Tokyo adopted a demand-print method called open-batch processing, in which the user had a token card read into the system and extracted the job result. This method used by Tokyo University was revolutionary for its time. Figure 2 shows the procedure for open-batch processing at the Computer Centre of the University of Tokyo.

Cover of manual for OS7Sample descriptions from the OS7 manualManual binding
(secured with screws for replacement convenience)