The Core Memory Project



NCR Century Series

NCR Century 50

The NCR Century 50 System is the newest member of the NCR Century 50NCR series of electronic data processing systems. The system has been developed specifically for the user whose present data processing operations are being handled electromechanically perhaps by accounting machine or by a tab system but whose overall needs demand a faster and more efficient means of processing. The hardware/software combination of the NCR Century 50 System offers the first-time user a small, yet complete system with features especially designed to fill his needs.

High Performance and Low Cost

The small user's most pressing need is for a relatively inexpensive computer that offers fast, efficient processing. The NCR Century 50 System combines a minimum hardware configuration with powerful software to give the user high performance at low cost.

Ease of Operation

NCR also meets the user's need for an easy-to- operate computer. Operating instructions for the NCR Century 50 System are completely documented. All of the NCR Century's hardware units have control panels and indicators at a comfortable height, and all provide simple access for loading and unloading. Also, the hardware is arranged so that the operator need take only a few steps to service any of the units.

Reliability and Maintainability

The NCR Century 50 System meets the user's demands for a system with a high degree of operating reliability and maintainability. Reliability is attained from the extensive use of integrated circuits; maintainability is achieved with the standardization of circuit boards, which reduces the number of parts required to service the system.

Ease of Installation

The user who is converting to an electronic data processing system must give special consideration to electrical power, air conditioning, placement of cables, and space. The NCR Century 50 has been designed to keep these requirements at a minimum.

Ease of Programming

The NCR Century 50 uses the simple, near-English instructions of the NEAT/S programming language. Although the computer needs detailed machine instructions, the user need only write his programs in this simple language; the NCR- supplied software interprets the NEAT/S instructions and forms the detailed machine instructions internally. To further aid the user's task, NCR provides both prewritten routines to perform common computer operations and complete user programs for many common commercial applications.

Upward Compatibility

NCR has designed the NCR Century 50 System realizing that the small user may need to acquire a larger system as his operations grow. For this reason, the NCR Century 50 has been made compatible with the other members of the NCR Century Series. This enables the user to upgrade to a larger member of the series without rewriting his existing programs.



The hardware components of the NCR Century 50 System are a Central Processor, a Dual-Spindle Disc Unit, a Punched Card Reader or a Punched Paper Tape Reader (depending on the user's choice), and a line Printer. An additional Dual-Spindle Disc Unit and an I/O Writer are also available on an optional basis.



The heart of any electronic data processing system is the central processor. This unit is the center of activity during any operation performed on the system.


The memory of the NCR Century 50 System's Central Processor is made up of short, magnetic thin-film rods. Each rod serves as storage for one bit; each character (letter, number, or symbol) requires eight bits. The standard storage capacity of the NCR Century 50 is 16,384 characters; however, memory size can be expanded to 32,768 characters if desired. Since internal operations in the NCR Century 50 are executed one character at a time, each character is separately addressable. The time required to access (store or retrieve) one character is 800 nanoseconds.


The NCR Century 50 System is controlled by the user through the operator's console. This control panel contains the indicators, rotary switches, toggle switches, and push button switches needed to operate the system. The console's control panel also contains a running-time meter, a compute-time meter, and a maintenance counter. These meters provide the user with valuable information for time studies, billing, and maintenance scheduling.



The NCR Century 50 System's Dual-Spindle Disc Unit contains two spindles for two disc packs that may be independently mounted or removed. These disc packs perform a vital function in the operation of the system because they contain the system's operating software in addition to the user's files. The storage capacity of each disc pack is 4,194,304 characters, providing access to over eight million characters on the dual-disc unit. This unit has an average access (read or write) time of 153 milliseconds, or 65 milliseconds on an optional basis.



The Printer included with the NCR Century 50 System is capable of printing 200 lines per minute. With this model, the user has his choice of either a 52- or 64-character set of alphabetic characters, numeric characters, and special characters. Two other models of the Printer are available on an optional basis. Both of these printers have faster printing speeds: 300/450 lines per minute when printing alphanumeric; 600/900 lines per minute when printing straight numeric. All models use 132 print positions, and all accept paper or forms of different widths, lengths, and weights.



The user of an NCR Century 50 has his choice of either a Punched Card Reader or Punched Paper Tape Reader to input control information to the processor. The system paper media reader, which is commonly referred to as the COT (card or tape) Reader, may also be used to read data files for input to user's programs.

System Punched Card Reader

The system's Punched Card Reader reads standard, 80-column cards photoelectrically, one column at a time, translating the data to 8-bit characters that can be recognized by both the hardware and software.

The NCR Century Punched Card Reader reads 300 cards per minute. The feed hopper and output stacker, which have a capacity of 1000 cards each, are easily accessible. The transport mechanism maintains constant contact and control of the cards as it guides them through the Reader, minimizing card jams and wear.

System Punched Paper Tape Reader

The system's Punched Paper Tape Reader can read paper tape at 1,000 characters per second in any code, and it can accept a wide variety of tape sizes (11/16, 7/8, or 1 inch) and formats (5-, 7-, or 8-channel).



The user of an NCR Century 50 has the option of having an I/O Writer installed with his system. This unit, which is similar in appearance to a typewriter, facilitates the communication between the user and the processor that is normally handled through the console indicators and switches. The processor uses the I/O Writer to print out software and user messages; the operator uses it to enter data and message responses.



The second major component of an electronic data processing system is the software - the programs supplied by the manufacturer to direct the computer's internal operation. The software supplied with the NCR Century 50 System is an extensive package that includes the operating system, utility routines, applied programs, and the NEAT/S Compiler. These programs have been designed to perform specific functions but, at the same time, to interact with one another to increase processing efficiency and to avoid duplication.

To conserve valuable memory space, a large portion of the software package remains on disc; only the most frequently used portion resides in internal memory all of the time. The disc-resident software is organized into small modules that are called into memory as needed to perform specific functions.

The memory-resident portion of the operating system maintains strict control of processing. It consists of routines, subroutines, lists, and tables that are used to perform common program functions, such as processing input/output operations, calling other software routines from disc as needed and processing errors.

The disc-resident portion of the operating system contains routines that are used less frequently in system operation, such as the peripheral-related software routines which are used for correcting errors encountered on the various units, and the log and display routines which record unusual operating conditions in the system log. The disc-resident portion of the operating system also contains Monitor, the software program that supervises the loading of utility routines and the user's programs.

Utility Routines

Another major portion of the software package consists of prewritten programs, called utility routines that perform functions frequently needed during system operation. These routines have been incorporated into the software package to save the user valuable programming time and to facilitate the operation of his system. The utility routines perform a wide variety of functions. Disc-related utility routines enable the user to initialize, print, and copy disc packs. System-related utility routines enable the user to print the system log and aid the user in debugging (correcting) programs. Other utility routines enable the user to sort data files and to print data stored in punched card and paper tape files. The utility routines are stored on a disc pack and are called into memory when requested by the user.

Applied Programs

NCR offers the NCR Century 50 user prewritten and completely debugged programs for the most common business applications. These programs reflect the most up-to-date methods and practices known in business and industry.
All applied programs consist of sections which may be modified individually for optimum operating efficiency under the .varying requirements of different users.

NEAT/S Compiler

The language used to program the NCR Century 50 is a subset of NCR's NEAT/S programming language, which consists of several types of instructions that enable the user to communicate with the computer. The instructions must be presented to the computer, however, in a language that the computer can understand. The NCR Century 50 allows the programmer to express his instructions in the NEAT/S programming language's near-English statements, such as GET (GET a new record), PUT (PUT the record out to a file), MOVE (MOVE this data to a new location), COMP (COMPARE this data to existing data). The NEAT/S Compiler then converts the programmer's instructions (source program) to machine language (object program) which the computer's processor can recognize and execute.



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