JPS5994212A - Record control system of magnetic tape - Google Patents

Abstract

PURPOSE:To write the next data block DB without disturbing the recorded DB by having retrogression of a prescribed length after detecting the existence of an inter-block gap when the new data is recorded at the rear side of the final record data block DB and then recording the next DB when both conditions are satisfied, i.e. a magnetic tape goes forward by a prescribed distance and the record DB is not detected yet at that time point. CONSTITUTION:When a tape starts its forward traveling at a point C after the positioning action is started, the tape traveling speed is measured by a tape traveling distance/speed measuring circuit RDM. When this measured value exceeds a prescribed value (point D), the reading is restarted for the data DB1. It is supposed for a write head WH to start the writing when the circuit RDM measured that the head WH reaches a point F. At this time point, the termination of the DB1 can be detected since a read head RH is positioned at a point E. Therefore no disturbance of data is produced by supplying a current to the head WH when no read output exists any more.

Description

[Detailed Description of the Invention] (1) Technical Field of the Invention The present invention provides a method for recording a new data block by reliably providing an ink block gap without disturbing the data of the previously recorded data block. This article relates to a magnetic tape recording control system.

(2) Prior Art and Problems Conventionally, it is known that data blocks to be recorded are divided into arbitrary lengths and recorded on a magnetic tape via interblock gaps. In Figure 1, DBl
, DB2 are data blocks on tape TP. The size of the interblock camp IBG is standardized depending on the data distribution density. Since the tape running mechanism has inertia, at normal tape running speed, the end of the data block DBI, that is, the ink block gap IB.
Even if you give a command to stop running at the starting point of G, the tape cannot stop immediately, and considering the position of the head facing the tape, head 0
exceeds the interblock gap IBG length, advances until it passes the next data block position, and finally stops. The situation is shown in the tH2 diagram. In FIG. 2, the arrows indicate the movement of the write head WH. Collapsible head W
The relative movement between H and tape TP is commonly called "positioning excitation." To explain the conventional positioning operation, the write head writes the instruction data from the center opening device to the data block DBI, and then when it reaches point A in the figure and there is no write instruction for block DB2, a "command overrun" occurs. '', the writing head WH is mechanically stopped from running and actually stops at the 8 points. Here, the current passing to the write head WH and the magnetic erasing head is cut off, and the head is moved back a predetermined distance Be and stopped at the zero point.

The 0 point is at a certain distance from the tip of the block DB2, and is often located inside the data block DBI. The running system is restarted from the 0 point, and when it is run in the forward direction for a certain distance, for example, 80%, a current is applied to the write head WH to initiate a write operation. In this operation, the length of tape travel is simply controlled by a travel distance measurement circuit using a tachometer, so if an error occurs in the travel system, the backward distance or forward distance may be incorrect, and the data may be lost due to slips, etc. New data block D on top of block DBI
In some cases, B2 was stored and data DB1 was destroyed, and the first part of data block DB2 became completely unusable.

(3) Purpose of the Invention The purpose of the present invention is to provide a magnetic recording control device which improves the above-mentioned drawbacks and reliably sets an interblock gap and praises the next data block without causing the data blocks that have already been recorded to be misprinted. There is something to do.

(4) Structure of the Invention The structure of the present invention to achieve the above-mentioned object is a magnetic tape recording control that records and reproduces data blocks in which data to be recorded is divided into arbitrary lengths via interblock gaps. In this method, when recording LR standard data after the last recording data block, the playback head detects the existence of an interblock gap, stops traveling, moves backward for a predetermined length, and then travels a predetermined distance in the hard direction. The next data block is recorded on the tape when both the following conditions are satisfied: and the recording data block is not detected at that time.

(5) Embodiment I@3 of the invention is a block diagram showing the configuration of a magnetic reproducing system as an embodiment of the invention. Tape TP is driven by drive device DR
Y causes the mirror to be driven in both reverse directions, and the direction in which it winds to the left is the forward direction.

RH is a reading head, WH is a writing head, and the interval between them is set to be shorter than the ink block gap IBG length. T.O.
M is a tachometer, RDM is a odometer/tape speedometer side circuit, l'1D (i is a reading circuit, WHO is a writing circuit,
OTI indicates a control circuit. When the positioning operation is started in the same way as in Fig. 2, and forward running is started from the 0 point as shown in Fig. 44, the tape running speed is measured by the tape running distance/speed needle side circuit RDM, and as shown in Fig. 4. CD point when reaching 5 predetermined value or more as shown in ), data DB
Wjt of 1, reading is resumed by the read head RH. As for the write head WH, when the tape running distance counting circuit R1)M calculates that it has reached 2 points (for example, 01 to 80% is reached), writing is supposed to start. However, since the reading head RH is at 8 points in FIG.
Around this time, the end of data block DB1 can be detected. Therefore, when the read output from the read head RH disappears, that is, after passing the end of the data block DB1 and confirming that the tape is within the range of the interblock gap IBH, the current is sent to the write head WH. Such data confusion does not occur.

Figure 5 shows a control circuit OT for performing the above-mentioned control.
In the block diagram showing an example of L, the output of the running distance/tape speed measuring circuit RDM and the constants determining the positions of the two points described above are compared by a comparator CMP to detect a match. Block recognition enclosure BI monitoring output from read head RH
The IIC detects the end of the data block DB1, performs logical AND-1 with the coincidence signal from the comparator, and then performs AND-2 when the convolution instruction signal WS arrives from the central controller. It is calculated and used as a signal to the write hand WH.

(6) Effects of the Invention As described above, according to the present invention, when a slip occurs in tape running or a mechanical error occurs in the drive device, the data block read signal can be detected during the positioning operation. It is possible to clearly set interblock gaps and record data without committing new data blocks. Therefore, there is an effect that the recorded data has high reliability.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing data blocks on a magnetic tape having interblock gaps, FIG. 2 is a diagram explaining a conventional positioning operation, FIG. 3 is a block diagram showing an embodiment of the present invention, and FIG. The figure is a positioning system diagram of the present invention, and the SCS diagram is a block diagram showing the control circuit of FIG. 3 in more detail. TP... Magnetic tape DBl, DB2.
...Data block IBG...Interblock ganging WH...Write head WH...Read head
TOM... Tachomeme RDM... Tape mileage and running speed Summer Itf side circuit C1TL... Control circuit Patent applicant Fujitsu Co., Ltd. representative Patent attorney Eisuke Tsuchi Suzuki

Claims (1)

[Claims] A magnetic tape recording control method for recording and reproducing data blocks in which data to be recorded is divided into arbitrary lengths is recorded and reproduced via interblock gaps.When recording new data after the last recorded data block, The reproducing head detects the presence of an ink block gap, stops traveling, moves backward for a predetermined distance, and then 7P) r detects that it has traveled a fixed distance in the forward direction and that no recording data block is detected at that point. A magnetic tape recording control method characterized in that when both conditions are satisfied, the next data block is recorded on the tape.