IBM System/7 Functional Characteristics - All about the IBM 1130 ...

RequestThis switch serves a dual function in the operator station. When momentarily pressed once,the request switch generates an interruption request to the processor and sets indicatorbit 0 in the operator station interrupt status word. A light inside the request switchturns on under program control when the operator station is in remote mode to indicatethat the program requires information from the keyboard.EOM (End of Message)This switch, when momentarily pressed once, generates an interruption request to theprocessor and sets indicator bit 3 in the operator station interrupt status word. The keyboardmust be enabled; that is, the request switch light is on.LocalThis switch places the operator station in the local mode of operation. When in localmode, the operator station is disconnected from the system and can be tested by the CE orused as a tape punch to prepare tapes for subsequent use.The local switch also turns on the motor if it has been turned off by the motor-offswitch.PunchThis switch turns on or off the paper tape punch when the operator station is in local modeof operation. The switch is pressed once to turn on the punch, and once to turn off thepunch. When the tape punch is turned on and the operator station is in local mode, anycharacter read from the tape reader or entered from the keyboard is punched into papertape.INITIAL PROGRAM LOAD (IPL)The two right-hand storage data/address switches must be set to a load unit address ofhexadecimal 00 prior to performing an initial program load operation from the tape readerin the operator station.When the program load key on the System/7 operator console is pressed, a system resetoccurs and the operator station adapter turns on the motor, locks the keyboard, disablesthe printer, and feeds tape until a hole is detected (that is, a nonzero character is read).The adapter then starts to transfer characters, two characters (bytes) at a time, inorder to fill each 16-bit storage location word. Storing begins with location 0 and continuesconsecutively until location 127 is filled. (See Figure 9-3.)The System/7 cannot be interrupted during this data transfer. Any error detected duringthis portion of the IPL procedure requires operator intervention. If an error occurs, thetape stops moving, but the load light on the system operator console remains on until resetby the reset key.Following the transfer of 128 words of data, a branch is made automatically to location 0and the system begins executing instructions on priority level 3. At this time, the tapestops moving, but the operator station motor remains on.The IPL operation just described can also be started by the auto restart function. Whenthe IPL operation is complete and program execution begins, bit 0 of the level 3accumulator will be set off if the IPL was a result of the program load key. Bit 0 will beset on if the IPL was the result of an auto restart operation. (See "Auto Rstrt Switch"and "Program Load Key" in Chapter 5.)IBM 5028 Operator Station 9-5...r.m.•••••9