IBM System 360/40

IBM 360/40 számítógép központi egység

The IBM 360 was a system announced by IBM in 1964, and delivered from 1965.

The most widely used model was the middle-range Model 40, with integrated circuits. The machine, just like its companion systems is universal with respect to applications, as it can be used for commercial, technical or scientific, as well as remote data processing and even process control purposes.

Its dual-address instruction set contains text (byte) and fixed-point (16-bit and 32-bit words) based, as well as floating-point (64-bit) commands. Multiprogramming is supported by further special instructions. It features 8-bit byte addressing, with a memory between 32k and 128k. The magnetic tape and disk drives used as external storage are handled by two selector channels, while slower peripherals are controlled by a byte-multiplexer channel. The machine’s license included ASM, RPG, FORTRAN, COBOL and PL/1 language compilers. Also, an operating system was provided based on configuration: TOS for systems without a disk drive, DOS - with foreground/background partitions -, or OS MFT - with a fixed number of memory partitions - for the largest configurations.

Operating systems are better at providing human-machine interfaces than control panels, while implementing different forms of multiprogramming. Background storage units included 9-channel - byte based - magnetic tapes and 7.25MB disks. The system could be equipped with larger capacity disks and mass storage devices as well. Slow speed peripherals included punch tape and punch card readers, mark sensing and OCR, as well as controllers for implementing remote data processing for remote work, data entry and data transfer. Later, terminal options in the modern sense also began to appear, such as the PL/1 system or the APL terminal. In Hungary, the 360/40 appeared relatively late, in 1971, as IBM strictly complied with embargo policies. By that time, a number of different byte based computers - ICL, Siemens - were used in Hungary.