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Diagnosis of Magnetic Tape Positioning Servo Sensing Circuits

IP.com Disclosure Number: IPCOM000085984D
Original Publication Date: 1976-Jul-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Yakkel, GL: AUTHOR

Abstract

In diagnosing magnetic tape unit functions, it is desirable to be able to exercise a magnetic tape unit without using a magnetic tape for supplying servo timing and data signals. A program controlling unit contains a program for generating the series of signals supplied to the microprogrammed control register, for simulating servo signal detection without the use of servo-written magnetic tapes. Signals normally received from the tape include sync or timing signals, plus data or position indicating signals. These signal paths are OR'ed in the AO's with signals received from the microprogrammed control register. Of course, in the absence of magnetic tape, none of the normal signals are received for generating the servo sync or the servo data signals.

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Diagnosis of Magnetic Tape Positioning Servo Sensing Circuits

In diagnosing magnetic tape unit functions, it is desirable to be able to exercise a magnetic tape unit without using a magnetic tape for supplying servo timing and data signals. A program controlling unit contains a program for generating the series of signals supplied to the microprogrammed control register, for simulating servo signal detection without the use of servo-written magnetic tapes. Signals normally received from the tape include sync or timing signals, plus data or position indicating signals. These signal paths are OR'ed in the AO's with signals received from the microprogrammed control register. Of course, in the absence of magnetic tape, none of the normal signals are received for generating the servo sync or the servo data signals.

The programmed controlling unit supplies a signal setting a diagnostic mode in the magnetic tape unit. This mode enables the A2 input portions of the illustrated A0 circuits. Then the program manipulates the N/2 and Nth bits of the microprogrammed control register generating sync and data bits. As the program controlling unit exercises the magnetic tape unit, the eye of the sync and data bits, in response of the magnetic tape unit, is checked by the monitor. Traditionally, the remaining bit positions of the microprogrammed control register may be further assigned to other functions as may be desired. When the Diagnostic Mode Bit One is reset, the bit positi...