BOS and ROS were the operating systems (hereinafter “OS”) for Fujitsu’s medium general-purpose computers FACOM 230-25 and FACOM 230-35, and were announced in August 1968. BOS (Batch Operating System) was an OS designed mainly for medium-scale batch processing and was completed in June 1969. ROS (Real-time Operating System) was an OS designed mainly for real-time processing and was completed in December 1969.
 In October 1971, BOS II, which achieved multiprocessing and provided an online control function called SOM (Standard Online Module) was completed as a higher-level OS beyond BOS.
 In November 1974, BOS/VS, which realized virtual memory control, was completed as a successor OS to BOS. Incidentally, VS showed Virtual Storage and Storage meant memory.
 The following describes the brief history of the OSs for Fujitsu’s medium general-purpose computer series FACOM 230-5 and FACOM 230-8, and the features of the OSs.

1. Brief history of OSs for the FACOM 230-5/8 series medium general-purpose computers

 Fujitsu announced three models of the FACOM 230-5 series (FACOM 230-25/35/45) in August 1968. It also announced BOS and ROS as the OSs for FACOM 230-25 and 35 at the same time.
 At that time, there was growing demand for real-time processing. However, in order to respond to that demand it was necessary for an OS to adopt a multitasking function, and many resources including memory were required. By contrast, for batch processing, it was preferable to downsize the system and minimize its price by imposing some limits. To achieve these goals, Fujitsu developed two types of OS: BOS designed mainly for batch processing as a medium-scale general-purpose OS, and ROS designed mainly for real-time processing.
 In addition, in November 1971, Fujitsu also developed BOS II, a new OS that made it possible to execute batch processing and small-scale online processing simultaneously. BOS II also provided an online control function called SOM.
 In August 1973, Fujitsu announced the medium-scale general-purpose OS BOS/VS, which supported virtual memory as the OS for FACOM 230-28 and FACOM 230-28S, which were lower models in the FACOM 230-8 series.
 BOS/VS was succeeded by the medium-scale general-purpose OS OSIV/F2 for the M series.
Table Brief history of OSs for medium-scale general-purpose computers
OS name Features Announcement date Completion date
BOS For medium-scale batch processing. Capable of simultaneously executing one batch process and up to two sub processes. August 1968 June 1969
ROS OS for small-to-medium scale real-time processing. August 1968 December 1969
BOS II Multiprocessing of up to 4 jobs - October 1971
BOS/VS Virtual memory control August 1973 November 1974
2. Features of BOS

 BOS was a medium-scale general-purpose OS designed mainly for batch processing, and had the following features:

(1) Increased processing efficiency by effectively using a high-speed system drum unit (FACOM 628).
(2) Capable of simultaneously executing one main process called “mainframe” (batch processing) and two sub processes called “sub-frame” (e.g. inquiry processing). In addition, it enabled one-key operation using the start/stop key for each frame on the console.
(3) Realized a paging function with software control, and allowed use of the memory at a capacity level higher than the actual capacity.
(4) Allowed program creation in compiler languages such as COBOL and FORTRAN.
3. Features of ROS

 ROS was a medium-scale general-purpose OS designed mainly for small-to-medium scale real-time processing, and was completely different from BOS, which was developed in the same period. ROS had the following features, of which provision of an online common package called COP-F (online COmmon Package File oriented system) for building an online system was the most notable:

(1) Supported a multitasking function to realize real-time processing.
(2) Realized functions for roll-in/roll-out and overlay control using a system drum in order to enable various types of control even with small-capacity memory.
(3) Provided online common package COP-F for FACOM 230-35 in order to facilitate creation of an online system. Previously, the company had offered a single-function package for one business application program, which operation was exchange-type or interactive-type. However, COP-F provided a package consisting of controls specific to online systems and of support programs required for developing application programs, for not only a single business application but also complex business applications.
4. Features of BOS II

 BOS II was a higher-level OS beyond BOS, developed with the aim of realizing small-scale online processing in parallel with medium-scale or large-scale batch processing. BOS II was operated on FACOM 230-35 and on FACOM 230-25, for which the memory was extended to 128 kilobytes. BOS II had the following functions, of which provision of SOM (Standard Online Module) was the most notable feature:

(1) Eliminated the sub-frame from BOS to enable multiprocessing of up to 4 programs.
(2) Provided useful programs as follows in order to perform online processing control. SOM (Standard Online Module) supported standard functions required for online processing. LCP (Line Control Program) managed the communication lines and terminals and controlled data transmission. RBM (Remote Batch Module) realized remote batch processing.
(3) Added a communication function to COBOL, allowing the user of SOM to develop an online application program in COBOL.
5. Features of BOS/VS

 BOS/VS was a medium-scale general-purpose OS that was developed based on BOS in order to inherit the assets of BOS, and it realized virtual memory. BOS/VS was succeeded by medium-scale general-purpose OS OSIV/F2 for the M series. BOS/VS had the following features:

(1) Realized a virtual memory space consisting of up to 3 partitions by using the HPA (high-speed page address) mechanism of the hardware.
(2) Increased operability by providing a simplified operation with color-console display, a multi-console function and an automatic spooling function.
(3) Allowed development of simplified online application programs using SOM (standard online module) and COBOL, as with BOS II.
(4) Was compatible with BOS in respect of job control statements, source programs, object programs and data files.