A folder of reports, notes and engineers forms relating to the KDF9 interrupt test. This includes a report entitled 'Tape Generator' containing details of the general characteristics of the tape generator, program tape items, specification of code, the layout of program tape, the operation of the tape generator and the sum-checking facilities as well as extracts from a series of KDF9 instructions. Also included is a handwritten flowchart, a report entitled 'interrupt Test (Non Time Sharing) Programme No. T. 680', a handwritten note entitled 'Test Interrupt Sequence - Non-time-sharing', a draft report entitled 'Interrupt Test (Non Time Sharing) Programme No T 680', a flowchart entitled 'Interrupt Test'. Finally there is a report entitled 'Interrupt Test (Non Time Sharing) Programme No T 220 and a note from J.R. Ollerenshaw to J. Lucking relating to complaints about the interrupt test and another from J.R. Lucking to J. Ollerenshaw relating to issues with this test and some suggestions to remedy it.