IBM 610 Manual Of Operation

Also see for 610: Technical overview and introduction

CONTROL DEVICES 23w u oyALL I N CLASS OFigure 10. Tape Representation of Entire ProgramNote that the carriage return (CR) instructioncauses the return of the typewriter carriage beforeread-out (RO) so that the results can be tabulatedin a vertical column. (These two operations will beexplained with the output commands.)Once the program of calculation has been com-pleted and stored on tape, the operator turns oflF thePUNCH switch and turns on the dup switch. Withthe DUP switch on, the information read by the pro-gram reader will be treated as instructions and willsimultaneously be repunched by the program punchinto blank tape immediately following the first pro-gram. Thus, after a given program has been executed,it has been repunched and moved into the slack loopavailable at the input of the program tape reader foruse in subsequent operations.The computer is now ready to repeat the routineas many times as may be desired. To begin processingthe second set of data, the operator depresses the ptrkey, transferring control to the program tape reader.The machine proceeds with the calculation until it istime for a numerical entry, at which point it returnscontrol automatically to the keyboard (as indicatedby the kb light coming on).The operator keys in the appropriate number and re-turns control to the program tape reader by againdepressing the ptr key. This process is repeated untilthe data to be processed has been exhausted with theprogram tape being automatically repunched eachcycle and the answers being typed out in a verticalcolumn for all pairs of Nj and Nj entered.Of special interest is the fact that while the pro-grammer was setting up the automatic program onthe keyboard, the first set of data was actually proc-essed. Thus on the 610 the programming itself doesuseful work.DATA TAPEThere may be occasions when it becomes desirableto record final or partial results in punched paper-tape form, either permanently or temporarily forlater use during the computation. Of the two paper-tape punches on the 610; one of these, called the DataTape Punch, is normally used for these purposes. Theoperator may direct the machine to punch informa-tion into this data tape. This tape can accumulate inthe machine up to fifty feet and can be automaticallyread back into the 610 at a later time if desired. Re-sults of the processing of several sets of data may bestored in the data tape and printed out at one time.Reading-ln from Data TapeIf the operator has punched data into the data tapefor automatic entry, he will want to write a pro-gram that secures data from the data tape as requiredby the program.(Data Tape Read)When this command is given, the data tape readeris turned on and the next number punched in thetape is read and transferred to the selected storageregister on the magnetic drum. At the end of eachsuch number on the data tape, a special two-charactersymbol (called the word-end symbol) is punched.When the word-end symbol is read by the tape reader,an electrical impulse is sent to the control panel. Thisimpulse must be used to transfer program control tosome other control device by means of control-panelwiring (i.e., to the control panel itself, to the key-board, or to the program tape reader) ; otherwise, themachine will continue to read data from the tape untilit runs out of tape or until the master stop switch isturned off. When the data tape reader is used, it isabsolutely necessary that the word-end on the con-trol panel be wired to activate a control device. Afull discussion of control-panel wiring is given in alater section.The data tape will be treated at greater length inthe output section of the manual.