NCR 315

The NCR 315 Data Processing System, released in January 1962 by NCR, is a second-generationcomputer. All printed circuit boards use resistor–transistor logic (RTL) to create the various logic elements. The magnetic-core memory is divided into 12-bit addressable units called slabs. The instructions can use a memory slab as either two 6-bit alphanumeric characters or as three 4-bitBCD digits. Basic memory is 5000 slabs (10,000 characters or 15,000 decimal digits), which is expandable to a maximum of 40,000 slabs (80,000 characters or 120,000 decimal digits) in four refrigerator-size cabinets. The main processor includes three cabinets and a console section that houses the power supply, keyboard, output writer (an IBM electric typewriter), and a panel with lights that indicate the current status of the program counter, registers, arithmetic accumulator, and system errors. Input/Output is by direct parallel connections to each type of peripheral through a two-cable bundle with 1-inch-thick cables. Some devices like magnetic tape and the CRAM are daisy-chained to allow multiple drives to be connected.

The central processor (315 Data Processor) weighed about 1,325 pounds (601 kg).

Later models in this series include the 315-100 and the 315-RMC (Rod Memory Computer).