DD215199B1 - CIRCUIT ARRANGEMENT FOR ERROR-RELATED CONTROL AND ELECTRONIC SWITCHING OF A MAGNETIC TAPE UNIT AS A TESTING AND CLEANING DEVICE FOR MAGNETIC TAPERS - Google Patents

Abstract

The invention has the goal that a magnetic tape device can be used in computer equipment without retooling both for the computing operation and for the testing and cleaning process. The circuit according to the invention includes a modification and supplementation of existing circuits of cable receivers for control and data lines for switching from arithmetic operation to testing of magnetic tapes.

Description

Field of application of the invention

The field of application of the invention extends to the testing and cleaning of magnetic tapes in electronic data processing.

Characteristic of the known technical solutions

Devices are known which are intended exclusively for the testing and cleaning of magnetic tapes in electronic data processing. Other devices that are primarily used for arithmetic operation must be retrofitted for use in testing and cleaning magnetic tapes by repositioning printed circuit boards or cables. A disadvantage of this design is that contact errors occur due to the necessary frequent conversion, which adversely affect the results. The test methods used did not meet the required standards in most cases.

The cleaning devices lead to a considerable mechanical stress and thus to reduce the useful life of the magnetic tapes. There is often a lack of automatic error logging and throughout

Test procedure, a supervisor is required.

The deficiencies of the known technical solutions can be attributed to the following causes:

- The previous magnetic tape devices of computer systems are intended only for computing;

- In some cleaning devices to solve any adhering contaminants from the magnetic tape this is pulled over its entire length at high mechanical stress on a blade;

- The logging of errors is not automatic, is inaccurate and a distinction between permanent and dynamic errors is not possible.

Object of the invention

The aim of the invention is to achieve that the data security in computing operation of computer systems increases, and without retooling a magnetic tape device can be used for both the computing operation and for the testing and cleaning process without a supervisor is required during the testing process.

Explanation of the essence of the invention

The object of the invention is to provide a circuit arrangement for error-dependent control and electronic switching of a magnetic tape device as a testing and cleaning device for magnetic tapes, with an easily evaluable logging of errors, a targeted cleaning of magnetic tapes with minimal mechanical stress and the test and Cleaning process and the error logging run automatically. According to the invention this is achieved in that an acted upon by an external start signal flip-flop (FF1) on the output side with a univibrator (G 3), a gate (G 6) controlled by a length meter counter (Z), continue the counter (Z) with its outputs is connected to a gate (G 9), a flip-flop (FF2), a gate (G 8) and an error detection circuit (F), the outputs of the error detection circuit (F) with the flip-flop (FF1), the gates (G 7, G 8) and an amplifier (N) and a non-vibrator (G 5) and via a switch (S 2) with the gate (G 9) are in communication and the output of the univibrator (G 5) with an input of Fehlererkennuhgsschaltung (F) , as well as a from the tape start signal (BA) controlled univibrator (G 4) with its output to a gate (G 7) and whose output to the flip-flop (FF2) are connected, continue lead lines for a stop signal to the flip-flop (FF 1) and (FF2) and for a ready signal to Fli Pflop (FF 1), the output of the gate (G 6) to an input of the gate (G8) and the error detection circuit (F), and the output of the univibrator (G 3) to an input of the gate (G 6) and the output of the gate (G 9) to an input of the flip-flop (FF1), and further are for switching through the signals required for a test operation on an existing and known cable receiver for control lines diodes (D1 ... D9) with their anodes to the respective base connected by transistors (T1 / 1 ... T1 / 9) and led out with their interconnected cathodes on an input (B 1), also gates (G 1/1 ... G1 1A) output side with the corresponding inputs of the gates ( GA) and on the input side a common control line (B2) and for the gates (G 1/2 ... G1 / 4) the additional inputs (LR, AZ and L) are created and also in an existing and known cable receiver for data lines each an entrance v separated on gates (GA1 ... GA9) and connected to the output of an additional gate (G 2), which is controlled via an input (P) and existing blocking inputs of the cable driver via a line (BT) are connected, wherein the switch from the tester on data storage a switch (S 1) is provided. '

Embodiment.

The invention is explained in more detail below with reference to a preferred embodiment. In the accompanying drawings show:

1 shows the circuit change of the magnetic tape recorder "EC5017-2" for switching from computer operation to testing; FIG. 2 shows the circuit arrangement for error-dependent control.

As shown in Fig. 1, the cable receiver for control cables has been extended with the diodes DI to D9 and the NAND gates G1 / 1 to G1 / 4 with two inputs each and an open collector. The additionally required inputs are routed to free contact points of the circuit board. The anodes of the diodes D1 to D9 are respectively connected to the base of the transistors T1 / 1 to * Ti ^. The cathodes are connected in parallel and led out on the input B1. The NAND gates G1 / 1 to G1 / 4 have a common input B 2. The outputs of these gates are connected to the inputs of the respective gates GA / n. The resistors R 5 / n serve as a working resistor for the output transistors of the gates G1 / 1 to G1 / 4. For the function "arithmetic operation", the input B1 leads,-potential, the diodes D1 to D9 are blocked, the input B2 has L-potential and the outputs of the gates G1 / 1 to G1 / 4 have Η-potential The interface signals IS1 to IS9 can become effective in the usual way.

For the "Check" funiction, B1 = L and B 2 = H. The diodes D1 to D9 are low impedance and incoming interface signals can not pass the receiver, the output of G1 / 1 becomes L and thus A1 = H (select signal) the gates G1 / 2 to G1 / 4, the signals formed by the control electronics of the tester E1, E2 and E3 at the outputs A2, A3 and A4 can be effective.

The cable receiver for data lines is changed such that each one of the three inputs of the gates GA / 1 to GA / 9 is combined on a common line and connected to the output of a gate G 2. With the input P = H, (corresponds to the function "arithmetic operation"), the interface signals ID1 to ID9 become effective at the outputs ABUS-O to ABUS-K. In the function "Check", the input P = L, all carry Outputs ABUS-O to ABUS-K constantly Η level. This is necessary for the selected function "Check." During this function, the cable drivers are disabled with the signal BT = L. The switch S1 switches over.

The contacts of the relay Re11 are used to switch through a recording cycle during the "Check" function and to switch on the operating voltage for the test electronics.

From Figure 2 it can be seen that a trigger FF1 by a start pulse, the signals L (run forward) and delayed by G3 via G 6, a recording signal (AZ). The delay lasts until the defined belt speed is reached. With AZ the error detection is activated. The signal L also controls the counting direction of a counter Z. If the MBG is not ready, due to a stop signal or a detected error (DF), FF1 is reset. The error detection takes place, for. For example, by conjunctively linking the read data in the circuit F. With DF, the trigger FF2 switches on the band return LR via G7. This function, controlled by G4, is only possible when the tape has run a defined distance from the beginning of the tape BA.

At the beginning of the tape retrace, the counter Z evaluates the length pulses, switches the direction with ER on G 9 again when the faulty tape position is again in front of the recording head and clears with RF the detected error in the circuit F. Is at the same band Error detected for the second or third time, an internal counter advances. After the third error, with the switch S 2 closed, a further tape advance (renewed read-write attempt) can be prevented by F3 via G 9 (definition: permanent error). In the other case (S2 open), via G5 an error suppression FU takes effect, which makes it possible to override the permanent error and to continue the automatic test. Furthermore, the signals F2 and F3 are evaluated by an amplifier V, which drives a device for error recording and classification with the output AF. Via the gate G8, after the second activation of a fault (F2) in connection with the signal ZM from the counter Z, the band is pulled over a cleaning blade at the next read-write attempt at the faulty point by a mechanism controlled by the signal KM.

Claims (2)

Circuit arrangement for error-dependent control and electronic switching of a magnetic tape device (MGB) as a testing and cleaning device for magnetic tapes, characterized in that a flip-flop (FF 1) which can be acted upon by an external start signal has, on the output side, a non-vibrator (G3), a gate (G 6), a counter (Z) controlled by the length measuring pulse, furthermore the counter (Z) with its outputs connected to a gate (G 9), a flipflop (FF2), a gate (G 8) and an error detection circuit (F), the outputs of Error detection circuit (F) with the flip-flop (FF 1), the gates (G7, G 8) and an amplifier (N) and a non-vibrator (G 5) and a switch (S2) with the gate (G 9) are in communication and the output of the univibrator (G 5) having an input of the error detection circuit (F), and a univibrator (G4) controlled by the beginning of the tape (BA) with its output with a gate (G 7) and its output with the F Furthermore, leads for a stop signal to the flip-flop (FF 1) and (FF2) and for a ready signal to the flip-flop (FF 1), from the output of the gate (G 6) to an input of the gate (G 8) and the error detection circuit (F), as well as the output of the univibrator (G 3) to an input of the gate (G 6) and the output of the gate (G 9) to an input of the flip-flop (FF 1), and continue to Circuit through the signals required for a test operation on an existing and known cable receiver for control lines in addition diodes (D 1 ... D9) connected with their anodes to the respective base of transistors (T1 / 1 ... ΤΊ / 9) and their interconnected Cathodes are led out to an input (B 1), furthermore, gates (G 1/1 ... G1 / 4) are connected on the output side to the corresponding inputs of the gates (GA) and on the input side a common control line (B2) and for the gates ( G 1/2 ... G1 / 4) the additional In addition, an input of gates (GA1 ... GA9) are separated in an existing and known cable receiver for data lines and connected together to the output of an additional gate (G 2), which leads via an input (P) is controlled and existing blocking inputs of the cable driver via a line (BT) are connected, wherein a switch (S 1) is provided for switching from the tester to data storage. For this 2 pages drawings