The first electronic digital computer ENIAC was developed at the University of Pennsylvania in 1946. It was not a stored program computer yet and its programming was provided through physical wiring. EDSAC, the world’s first stored-program computer, developed by Maurice Wilkes of University of Cambridge in 1949, had initial orders, an initial input routine, for storing a program described with symbols while reading and converting the program to binary codes. In the 1950s, commercial computers appeared and peripherals such as magnetic tape drives were developed in conjunction with improvements to the central processing unit, while advances were also made in software support. Early-stage programs were coded using machine languages, including hexadecimal numbers; support for assemblers and compilers followed. In 1957, IBM began providing the high-level language FORTRAN for scientific and engineering computing. The advent of high-level languages improved programming efficiency and enabled computers that used different machine languages to use the same programs. In 1958, ALGOL was introduced. And in 1961, COBOL was proposed as a language for business applications.
Around the end of the 1950s, second-generation transistor computers appeared, and computerization spread rapidly. Initially, each programmer operated the machines by himself to process his own program. Later, a monitor, early operating system was developed in order to improve the efficiency of processing . Batch processing was adopted to execute a series of programs on a computer without human interaction. Online systems and time-sharing systems(TSS) were developed in addition to batch processing systems, and the corresponding operating systems were also developed.
Over the two decades of the 1960s through the 1970s, operating systems development advanced rapidly. The first- and second-generation computers were categorized into those for scientific and engineering computing and those for business applications, and there was separate development of operating systems for batch processing, online processing and TSS. In 1964, IBM's announcement of the general-purpose computer System/360 integrated with a general-purpose operating system OS/360 was followed by widespread adoption and use of general-purpose machines and operating systems. As a result, most manufacturers shifted to production of general-purpose systems. The term "operating system （OS）" also became established. In addition, MIT and IBM developed the concept of a virtual machine, which was one step ahead of general-purpose operating systems, and IBM announced its virtual machine "VM/370" in 1972.
In Japan, initial orders were created for some early computers to follow EDSAC. From around the end of the 1950s into the 1960s, research and development of compilers such as FORTRAN and ALGOL started at universities, national laboratories and computer manufacturing companies in Japan. In addition, a large-scale computer center designed for nationwide shared use was installed at the University of Tokyo in order to promote Japanese computer technology research. Subsequently, Japan's first OS research and development project was implemented through collaboration between the University of Tokyo and Hitachi, and an operating system that adopted a multiprogramming technology was realized on HITAC 5020E.
In the United States, MIT's MAC project started in 1963, and a MULTICS system using a two-dimensional virtual storage was developed. MULTICS was regarded as the model for a general-purpose, large TSS. Because this system involved important policies such as strict protection based on the assumption of shared use, it had a significant impact on Japanese operating systems, particularly on research and development of TSS. In Japan, research on TSS began around 1967. Specifically, research activities were conducted at Keio University in cooperation with Toshiba, at Tokyo University with Hitachi, at Osaka University with NEC, at Kyoto University with Fujitsu, and at the Electrical Communication Laboratory of Nippon Telegraph and Telephone Public Corporation, the Electrotechnical Laboratory of Ministry of Communications and Kyushu University.
Starting in fiscal 1962, a plan for manufacturing a Japanese computer that could compete with IBM's large computers was implemented as the FONTAC project involving NEC, Oki Electric Industry and Fujitsu, supported by subsidy from the Ministry of International Trade and Industry (MITI, currently Ministry of Economy, Trade and Industry). This project also included development of a multiprogramming type OS as a research task. Fujitsu successfully realized that objective with the development of FACOM 230/50, 60 and 70. In 1965, it announced MONITOR II, which was developed based on the FONTAC OS. Subsequently, Fujitsu developed MONITOR V in 1968, MONITOR VII in 1974, and the largest OS, VII/F4, in 1975. In 1977, Fujitsu announced X8 for medium-size systems and F2 for small systems. Hitachi, in technical collaboration with RCA, developed HITAC 8000 series operating systems to compete with System 360. Hitachi developed OS7 for HITAC 8700/8800 in 1977 to realize functions that would ideally suited to the virtual storage method. NEC developed NEAC 2200 series machines in technical collaboration with Honeywell. NEC independently developed the large models NEAC 2200/500 and 700 and their respective operating systems, and developed OS/MOD IV, MOD IV EX, which had TSS functions. In 1968, it put Osaka University MAC into practical application through joint TSS research with Osaka University. NEC also developed OS/MOD VII, which was capable of performing batch processing, online processing and TSS processing.
In 1970, IBM announced System 370. To compete with it, Japanese computer manufacturers were grouped into three under the guidance of the MITI. Fujitsu and Hitachi developed an M series, NEC and Toshiba an ACOS series and Mitsubishi Electric and Oki Electric Industry a COSMO series. Fujitsu developed three operating systems: an ultra-large, general-purpose OS "OS IV/F4" for the FACOM M series, a large, general-purpose OS "OS IV/X8" with a high price/performance- ratio, and a medium-size, general-purpose OS "OS IV/F2," which was optimal for medium-size business operations. OS IV/F4 and F2 were announced in 1974, and OS IV/X8 in 1975. These three OSs were subsequently enhanced by the addition of various functions including new hardware support. Hitachi announced "VOS2," the first OS for the HITAC M series, in 1974, followed by a higher-level model VOS3 and a lower-level model VOS1 in 1975. Virtual machine systems VMS, VMS/ES and VMS/AS for the HITAC M series computers were developed and completed in 1979, 1985 and 1990, respectively. NEC and Toshiba began joint development of the ACOS series in 1972. When Toshiba withdrew from the general-purpose computer field in 1979, NEC assumed responsibility for all development work. The ACOS series systems took advantage of the MULTICS achievement to evolve from GCOS. ACOS-4 and ACOS-4/MVP were also appraised as systems that could be suitable for large-scale TSS based on the virtual method. In 1974, Mitsubishi Electric announced "UTS/VS," which supported the multiple virtual storage method and closely coupled multiprocessors, for the COSMO series. For the MELCOM EX series announced in 1985, Mitsubishi Electric developed GOS/VS, which offered substantially enhanced functionality. Thus, Japanese mainframe manufacturers succeeded in developing unique systems from the 1970s through the 1980s by implementing distinctive strategies.