【Fujitsu】 OSIV/F4

 OSIV/F4 (*) was one of the operating systems (hereinafter “OS”) for Fujitsu’s FACOM M series general-purpose computers, and was a super-large general-purpose OS. The OS was announced in November 1974 together with the super-large general-purpose computer FACOM M-190.
 The following describes the features of OSIV/F4, its major functions and functional enhancements.

*: OSIV/F4 was pronounced “OS four F four” The letters “OSIV” represented 4th generation OSs, and were added to the heads of the names of all OSs for the FACOM M series computers.

1. Features of OSIV/F4

 OSIV/F4 was newly developed in order to provide functions and performance at the highest level, and it had the following features:

(1) Achievement of a system with high levels of processing capacity, expandability and reliability
 The OS efficiently controlled the hardware of the FACOM M series, including a multiprocessor system consisting of up to 4 CPUs, by adopting a multiple virtual memory control, and it achieved high levels of system processing capability and expandability.
 In addition, it provided functions for building a high-reliability system in conjunction with the RAS (Reliability Availability Serviceability) function of the hardware.
(2) Provision of online database AIM (Advanced Information Manager)
 The OS provided the online database AIM, which integrated an online function and a database function based on a new concept, allowing the user to easily build an optimal online database system.
(3) Easy-to-use system operating functions
  In order to ease the burden on the operators, the OS provided easy-to-use functions of system operation, which were including functions for improving operability, a function for managing files in an integrated manner and a simple job scheduling function.
(4) Functions for realizing easy application development
 The OS provided high-level languages processing programs, an advanced function of the language-processing program to make program development easy, tools for TSS-based application development, and so on.
(5) International compatible functions
 The OS achieved compatibility with IBM OS/VS1 in job control languages, application programs (source codes and load modules), and data files.
2. Major features of OSIV/F4

 Major features of OSIV/F4 included:

(1) Functions for increasing the processing capacity and expandability of the system
 The OS was aimed at realizing high system processing capacity and system expandability through the following functions:
- Multiple virtual memory control function capable of allocating up to 1,536 16-MB virtual address spaces
- Tightly-coupled multiprocessor control function in a configuration consisting of up to 4 CPUs (achieved with FACOM M-200)
- Reduction of the overhead in the I/O control of the OS through utilization of channel DAT (Dynamic Address Translation) and channel cross call
- VSAM (Virtual Storage Access Method), designed to increase processing capacity and utilization of the file device
- VIO (Virtual Input Output) function for increasing the processing efficiency of the system
 The OS achieved acceleration of the I/O operation speed by allocating temporary files to a virtual memory space.
-Provision of VTAM (Virtual Telecommunication Access Method) and a network control program (NCP) that operated with a communication control processor (CCP)
The OS increased system efficiency though load distribution of the whole system, by having the NCP perform part of the functions that were formerly executed by the host computer.

Figure: Configuration (example) of the virtual spaces within the OSIV/F4 system

Figure: Configuration (example) of the virtual spaces within the OSIV/F4 system

(2) Online database AIM
 For AIM, the company categorized the functions required to establish an online database into the following five types, and provided corresponding software components:
- Message control (DCMS: Data Communication Management Subsystem)
- Database management (DBMS: Data Base Management Subsystem)
- Operation management (ISMS: Integrity and Schedule Management Subsystem)
- AIM system asset management (DDMS: Dictionary and Directory Management Subsystem)
- Support function (utilities)
 By selecting and combining functions of the software components, the user was able to easily create application programs for an online database system of any scale.
(3) System operation functions
 The OS provided a function for efficiently operating the system and a function for easily performing system operation.
- JES (Job Entry Subsystem) that managed entry of jobs and fetching of the execution results of jobs, in a unified and efficient manner
- MCS (Multiple Console Support) function that enabled the usage of consoles according to the purpose or/and application
- AVR (Automatic Volume Recognition) function that enabled efficient handling of volumes (volume: a handling unit of storage)
- SDM (System Decision Management) for assuring response of programs and effective use of system resources
- Function for managing storage files in an integrated manner
- Easy job scheduling function
- Center operation function with SMF (System Management Facilities)
(4) RAS (Reliability Availability Serviceability) functions
 For realizing a high-reliability system OSIV/F4 provided various RAS functions in conjunction with the hardware. A representative example of these functions was a recovery management function called RMS (Recovery Management Support). If hardware failure occurred in the main system unit or the I/O system, RMS recovered the system to the maximum extent through the OS. If RMS judged it impossible to recover from the failure, it isolated the problem device from the system to minimize the impact on the system, thereby allowing the system to continue operating. In addition, the OS provided ACR (Alternate CPU Recovery) function that automatically detached the problem CPU from the multiprocessor system and had another CPU terminate/recover the processes that were executing on the problem CPU. And also a configuration control function was provided for facilitating detachment and attachment of the CPU, main memory and channel unit.
3. Functional enhancement of OSIV/F4

OSIV/F4’s batch function, remote batch function, TSS function and online database AIM were completed in October 1975, February 1976, March 1977 and June 1977, respectively. Subsequently, various functional enhancements were implemented. Of these enhancements, the support function for the Japanese-language information system JEF (Japanese processing Extended Feature), announced in 1979, was one of the major functions.
 OSIV/F4 was succeeded by OSIV/F4 MSP (announced in June 1982), which extended its virtual memory address space from 16 MB to 2 GB (extended from 16-bit address to 31-bit address).

FACOM OSIV JEF instruction manual (cover)FACOM OSIV JEF instruction manual (part of content)