IBM 1130

The IBM 1130 Computing System, introduced in 1965, was IBM's least expensive computer at that time. It was aimed at price-sensitive, computing-intensive technical markets like education and engineering, succeeding the IBM 1620 in that market segment.

The 1130 was also used as an intelligent front-end for attaching an IBM 2250 Graphics Display Unit, or as remote job entry (RJE) workstation, connected to a System/360 mainframe.

The total production run of the 1130 has been estimated at 10,000. The 1130 holds a place in computing history because it (and its non-IBM clones) gave many people their first direct interaction with a computer. Its price-performance ratio was good and it notably included inexpensive, removable disk storage, with reliable, easy-to-use software that supported several high-level languages. The low price (from around $32,000 or $41,000 with disk drive) and well-balanced feature set enabled interactive "open shop" program development.

The IBM 1130 used the same electronics packaging, called Solid Logic Technology (SLT), used in System/360. It had a 16-bit binary architecture, as did later minicomputers like the PDP-11 and Data General Nova.

The address space was 15 bits, limiting the 1130 to 32,768 16-bit words (65,536 bytes) of memory. The 1130 used magnetic-core memory, which the processor addressed on word boundaries, using direct, indirect, and indexed addressing modes.

IBM implemented five models of the 1131 Central Processing Unit, the primary processing component of the IBM 1130. The Model 1 through Model 5 described the core memory cycle time, as well as the model's ability to support disk storage. A letter A through D appended to the model number indicated the amount of core memory installed.

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