NCR 315
Encyclopedia
The NCR 315 Data Processing System, released in January 1962 by NCR
, was a second-generation computer
. All printed circuit
boards used resistor-transistor logic
to create the various logic elements. It used 12-bit
slab
memory structure using core memory. The instructions could use a memory slab as either two 6-bit alphanumeric characters or as three 4-bit
BCD
characters. Basic memory was 5k of hand-made core memory, which was expandable to a maximum of 40 k in four refrigerator-size cabinets. The main processor included three cabinets and a console section that housed the power supply, keyboard, output writer (an IBM
Selectric-i typewriter), and a panel of lights that indicated the current status of the program counter, registers, arithmetic accumulator, and system errors.
Input/Output was 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 were daisy-chained to allow multiple drives to be connected.
Later models in this series include the 315-100 and the 315-RMC (Rod Memory Computer).
The primary difference between the older NCR 315 and the 315-100 was the inclusion of the Automatic Recovery Option (ARO). One of the problems with early generation of computers was that when a memory or program error occurred, the system would literally turn on a red light and halt. The normal recovery process was to copy all register and counter setting from the console light panel, and to restart the program that was running at the time of the error. Usually the restart was from the very beginning of the program.
The upgrade to the 315 required the removal of approximate 1800 wire-wrapped
connection on the backplane, and the installation of approximately 2400 new point-to-point wired connection.
. This reduced the clock cycle time to 800 nanoseconds. It also included floating-point logic to allow scientific calculations, while retaining the same instruction set as previous NCR 315 and NCR 315-100.
The thin film was wrapped around "rods" to allow faster reading and writing of memory.
NCR Corporation
NCR Corporation is an American technology company specializing in kiosk products for the retail, financial, travel, healthcare, food service, entertainment, gaming and public sector industries. Its main products are self-service kiosks, point-of-sale terminals, automated teller machines, check...
, was a second-generation computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
. All printed circuit
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
boards used resistor-transistor logic
Resistor-transistor logic
Resistor–transistor logic is a class of digital circuits built using resistors as the input network and bipolar junction transistors as switching devices...
to create the various logic elements. It used 12-bit
12-bit
Possibly the best-known 12-bit CPU is the PDP-8 and its relatives, produced in various incarnations from August 1963 to mid-1990. Many ADCs have a 12-bit resolution. Some PIC microcontrollers use a 12-bit word size....
slab
Slab (computer science)
A slab or syllable is the primary unit of memory in the NCR 315 computer architecture from NCR Corporation. Having 12 data bits and a parity bit, its size falls between a byte and a typical word . A slab may contain three digits or two alphabetic characters...
memory structure using core memory. The instructions could use a memory slab as either two 6-bit alphanumeric characters or as three 4-bit
4-bit
The Intel 4004, the world's first commercially available single-chip microprocessor, was a 4-bit CPU. The F-14 Tomcat's Central Air Data Computer was created a year before the 4004, but its existence was classified by the United States Navy until 1997...
BCD
Binary-coded decimal
In computing and electronic systems, binary-coded decimal is a digital encoding method for numbers using decimal notation, with each decimal digit represented by its own binary sequence. In BCD, a numeral is usually represented by four bits which, in general, represent the decimal range 0 through 9...
characters. Basic memory was 5k of hand-made core memory, which was expandable to a maximum of 40 k in four refrigerator-size cabinets. The main processor included three cabinets and a console section that housed the power supply, keyboard, output writer (an IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
Selectric-i typewriter), and a panel of lights that indicated the current status of the program counter, registers, arithmetic accumulator, and system errors.
Input/Output was by direct parallel connections to each type of peripheral through a two-cable bundle with 1-inch-thick cables. Some devices like magnetic tape
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...
and the CRAM were daisy-chained to allow multiple drives to be connected.
Later models in this series include the 315-100 and the 315-RMC (Rod Memory Computer).
NCR 315-100
The NCR 315-100 was the second version of the original 315. It too had a 8 microsecond clock cycle, 10-40K Memory.The primary difference between the older NCR 315 and the 315-100 was the inclusion of the Automatic Recovery Option (ARO). One of the problems with early generation of computers was that when a memory or program error occurred, the system would literally turn on a red light and halt. The normal recovery process was to copy all register and counter setting from the console light panel, and to restart the program that was running at the time of the error. Usually the restart was from the very beginning of the program.
The upgrade to the 315 required the removal of approximate 1800 wire-wrapped
Wire wrap
Wire wrap is a technology used to assemble electronics. It is a method to construct circuit boards without having to make a printed circuit board. Wires can be wrapped by hand or by machine, and can be hand-modified afterwards. It was popular for large-scale manufacturing in the 60s and early 70s,...
connection on the backplane, and the installation of approximately 2400 new point-to-point wired connection.
NCR 315-RMC
The NCR 315-RMC, released in July 1965, was the first commercially available computer to employ thin film memoryThin film memory
Thin-film memory is a high-speed variation of core memory developed by Sperry Rand in a government-funded research project.Instead of threading individual ferrite cores on wires, thin-film memory consisted of 4 micrometre thick dots of permalloy, an iron-nickel alloy, deposited on small glass...
. This reduced the clock cycle time to 800 nanoseconds. It also included floating-point logic to allow scientific calculations, while retaining the same instruction set as previous NCR 315 and NCR 315-100.
The thin film was wrapped around "rods" to allow faster reading and writing of memory.
Available languages
- NCR Assembler Language
- National Electronic Autocoding Technique (NEAT)
- COBOLCOBOLCOBOL is one of the oldest programming languages. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments....
- BEST
Available peripherals
- NCR-321 Communications Controller
- NCR-340NCR-340The NCR-340 was NCR's first line "High Speed" 300-line-per-minute computer printer. It used a drum made up of 120 hardened steel discs with the upper-case alphabet, the numbers 0-9 and a few special symbols. The discs were keyed on an armature, but could be changed if a character were damaged.The...
600-LPM line printer - Magnetic tapes
- NCR-332 Magnetic tape drive (512 bpi)
- NCR-333 Control Data CDCControl Data CorporationControl Data Corporation was a supercomputer firm. For most of the 1960s, it built the fastest computers in the world by far, only losing that crown in the 1970s after Seymour Cray left the company to found Cray Research, Inc....
tape drive (512 bpi) - NCR-334 Magnetic Tape Drive (200/512 bpi)
- NCR-353 Magnetic Card Random Access Memory (CRAM)
- Card and tape equipment
- NCR-361 Paper Tape Reader
- NCR-371 Paper Tape Punch
- NCR-376 IBMIBMInternational Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
Card Reader/Punch - NCR-380 2000 CPS High speed card reader
- NCR-472 Card Reader, Paper Tape Reader/Punch
- NCR-??? Drum memory
- NCR-402 MICR Check Reader/Sorter
- NCR-420 Optical Character Reader(OCROptical character recognitionOptical character recognition, usually abbreviated to OCR, is the mechanical or electronic translation of scanned images of handwritten, typewritten or printed text into machine-encoded text. It is widely used to convert books and documents into electronic files, to computerize a record-keeping...
) - NCR-407 High Speed MICR Check Reader/Sorter