On-Line Handling System for the NBS Linac

To meet the needs of the new Linac facility at the National Bureau of Standards, an SDS 920 digital computer has been obtained for concurrent on-line processing of data from several independent experiments. The system surrounding the computer contains several novel devices for allowing convenient real time operator control on computer functions and to provide privacy of programs by means of priority interrupt lines controlling the sequence of operation. A family of building blocks is being developed for the input of information. Surprisingly, the requirements of all nuclear physics experiments projected for the facility can be met with only six different blocks; an Analog Voltage Analog to Digital Converter, a Digital Register Unit, a Spectrum Analog to Digital Converter, a scaler, and a Group Enable Unit. These devices all feed information into the computer via a Multiplex Register Unit. The man machine interface is made flexible by the use of two decoding units, one for outgoing signals and one for sense switch type information to be used in computer control. The conventional computer output devices are supplemented in this system by direct analog, digital, graphic and scope output of data.