EXPERIENCE OPERATING tape drives TYPES Izotov 5003 and SM5300

EXPERIENCE OPERATING tape drives TYPES Izotov 5003 and SM5300

A. Fokin, head of the MCC group IPU

In the Main Computing Centre (MCC) MPS bundled with computers ES1010 as external storage devices operated tape drives (POC) types Izotov 5003 and SM5300.

To check the basic parameters and operating modes of storage (recording and reproducing information, measurements and settings skew line during recording and playback, measurement and adjustment of start-stop performance, test compatibility mode «Record» and «Play», measurement and adjustment of speed of movement) uses computer time ES1010 computers.

Manufacturing and introduction of the MCC MPS versatile device allows you to check the basic performance parameters POC autonomously economy «thus the machine time of computer. Schematic diagram of the device shown in Fig. 1. It consists of a clock generator with adjustable frequency from 5 to 50Hz oscillator clock frequency of 10 kHz, a type-setting field bus channel recording and playback SHZ BC, switch operation modes S1 … S5 and S6 rewind mode button. Dimension 120X90X50 mm devices.

The generator frequency 5 … 50Hz assembled on a chip D1 (K155LAZ). Potentiometer R1 provides a smooth frequency adjustment necessary to adjust the start-stop performance storage and synchronization of the oscilloscope.

■ 10 kHz generator consists of chip D2, (K155J1A3), capacitor C2 and resistor R2 serves to generate the recording timing drive.

Switched flexible jumpers typesetting field with tires SHZ recording channels can be set arbitrary codes in the recording. For example, the connection terminals of the field SZ with Key field OM provides a record of logical 0, and the lack of connections — 1 record across all channels POC. Terminals BC playback channels are used for visual control of the oscilloscope start-stop characteristics and skew line.

Modes POC checking device shown in the table. Here «+» denotes a closed and «-» open contact switches S1 … S5 and S6 buttons (see. Fig. 1).

Checked POC device is connected to a standard cable used to connect the POC and the control unit (CU), the interface board ZT15 of the cable is inserted into the connector XI device that is powered by POC checked. To do this, the cable POC — W contacts 11 and 12 drive connectors 02-11RR Izotov 5003 (contacts B13 and B1 connectors OZRV drive SM5300) are respectively connected to pins 8 and 0 board ZT15.

SM5300 drives have similar interface signals are connected to the computer and the EU in 1010 by three twisted-pair cables. Wiring cables made in accordance with Fig. 2. The boards POC set these jumpers: U-V, L-M, X-Y at 30X80, K-M (board «Management»); D-C, X-Z, F-G (the board «Record»); A-B, M-L (on-board «Play»).

Operating experience has revealed the dependence of storage stability of the speed of the magnetic tape (particularly in POC SM5300) on the cleanliness of the collector tacho. Therefore, the collector must be cleaned at least 1 times in two weeks.

It also found no signal EOT status word MEC. For its restoration — the transmission CPU signal the end of the tape — to Taizé SUP1 control devices on the circuit board assembly to cut the connection terminal 4 chips B1.

To ensure the stability of the frequency of clock signals in the W Taizé COL2 mounted crystal oscillator (Fig. 3). It is made on a quartz resonator (a chip D1 type K155LN1) a fundamental frequency of 2.7 MHz. The chip D2 (K155IE2) provides a frequency division by 5 chips D1 and D2 are set instead of the chips C2 and C4 (SN74121). Pilot operation of the generator shown an increased frequency stability and stable operation of the POC.

The MCC part of the information on the work of the railways introduced into ES 1010 tapes, recorded on a computer ES1033 and ES1045. Analysis of the data input into the computer ES1010 showed that reads from such tapes going unstable. There are several reasons. Each line of information received from the tape is analyzed in a computer ES1033 at the program level. The time T between lines (see. In the diagram in Fig. 4a) can vary within wide limits, it will have no effect when reading the information on a computer running on the software level. Time T may vary due to uneven movement of the magnetic carrier, on slipping belt driving roller, due misalignment drive start-stop characteristics, quality of the magnetic carrier and for other reasons.

The ES 1010 with the arrival of the line is a data analysis takes a certain branch of the firmware for the time t (Fig. 4b). Time t corresponds to the duration of 14 cycles of the signal frequency NCLK control device. If the read line information comes before the branch is fulfilled corresponding firmware (T’lt; t), this branch is interrupted and the information from the tape can not be read.

To ensure sustainable reading the information in the computer of the EU in 1010 have increased the frequency of clock signals W NML 30% of par, which reduced the time branch firmware (Fig. 4c).

In the top position of the switch S1 (see. Fig. 2) the frequency of the signal corresponds to the nominal NCLK — 180 kHz. In the lower position S1 in Taizé COL2 the relay K1 (RES55 passport 0302), which your contacts instead of the quartz oscillator connects D1.4 … D1.6 generator with a frequency of up to 30% more. At the same time it goes to zero SRE ERROR, thereby inhibiting the tape recording. This is necessary to eliminate the possibility of recording information on a frequency too high, ie. E. With a recording density greater than 32 bits / mm. To draw the operator’s attention to the fact that the switch S1 is in the down position, set VD1 LED type AL307A. It operates in flashing mode with a period of 1 second (1 Hz generator D1.3, D1.4). LED VD2 (type AL307B) indicates normal operation.

Operation of the upgraded scheme W POC demonstrated the effectiveness of its use when you enter information on the computer tapes ES1033 and ES1045, as well as devices of data preparation tape ES9004.

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