JP2989968B2 - Magnetic tape device and write head switching method in write circuit of magnetic tape device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a magnetic tape device adopting a serpentine recording system.
In particular, by electrically switching the write head (Write Head) driven according to the tape running direction,
Magnetic tape device and magnetic device that do not require movement of write head
The present invention relates to a write head switching method in a write circuit of a magnetic tape device .

[0002]

2. Description of the Related Art FIGS. 8 to 11 are views showing a conventional example, FIG. 8 is a diagram showing a configuration of a magnetic tape subsystem, FIG. 9 is an explanatory diagram of a parallel serpentine recording system, and FIG. FIG. 11 shows a time chart.

8 to 11, reference numeral 1 denotes a magnetic tape control device (hereinafter referred to as "MTC"), 2 denotes a magnetic tape device (hereinafter referred to as "MTU"), 3 denotes a microprocessor (hereinafter referred to as "MPU"), Is a write circuit,
5 is a read circuit, 6 is a servo circuit, 7 is a machine reel motor, 8 is a file reel motor, 9 is a machine reel, 10 is a file reel, 11 is a head, 1
3 is a magnetic tape, W1 and W2 are write heads, R1 and R
Reference numeral 2 denotes a read head.

[0004] Further, 15 is an inverter, 16, 17, 1
8 and 19 are AND circuits, 20 is a protection discrimination circuit, 2
Reference numerals 1 and 22 denote write power supplies, and reference numerals 23 and 24 denote write drivers.

Description of the magnetic tape subsystem ...
Referring to FIG. 8, as shown in FIG.
C1 and MTU2, and MTU2 includes MPU
3, a write circuit 4, a read circuit 5, a servo circuit 6, a machine reel motor 7, a file reel motor 8, a machine reel 9, a file reel 10, a head 11, and the like.

The MPU 3 is a processor for performing various controls in the MTU 2, and the write circuit 4 is a circuit for performing data write processing. The read circuit 5 is a circuit for reading data, and the servo circuit 6 is a circuit for controlling the machine reel motor 7 and the file reel motor 8.

The head 11 includes a plurality of write heads W
, W2,... And a plurality of read heads R1, R2.
.. Are controlled by the write circuit 4 and the read circuit 5 to perform data write (Write) or data read (Read).

The signals and the like in the figure are as follows. "W
TENB ": write enable signal (write enable signal) output from MPU 3 to write circuit 4," WP1 ": M
Head select signal "PRTCT" output from PU3:
The protection signal detected from the file reel 10, "W
“TDT”: write data, “ALERT”: signal for reporting an abnormality detection from MPU 3 to MTC 1 (error reporting signal by interruption), “WC 1”, “WC 2”, “*”
“WC1”, “* WC2”: write current to flow through the write head, “RDDATA”: read data, “FTAC,
"FTACB": tachometer output signal, "PH1O
N "," PH2ON ": Power supply inspection signal," MOVE ":
Operation command signal, "FWD": Forward command signal, "M
VERR ": Error signal.

Description of the Parallel Serpentine Recording Method--See FIG. 9 The example of FIG. 9 is an example in which the tracks on the magnetic tape 13 are 36 tracks. Use Therefore, the head 11 is provided with a plurality of write heads W1, W2,... W36 and a plurality of read heads R1, R2,.

[0010] A pair of write heads and read heads are provided at each track position on the magnetic tape 13. At the time of data recording, recording is performed by the parallel serpentine recording method while electrically switching such a head.

According to the parallel serpentine recording method,
When data is recorded, BOT (Beginning
EOT (End of Tap)
e) When traveling in the direction, the trucks 1, 3, 5,.
Then, data corresponding to each track is written simultaneously in parallel.

When the vehicle travels in the reverse direction from the EOT to the BOT, data is similarly written in tracks 2, 4, 6,... 36. At this time, since the head does not move in the vertical direction, at the time of writing, the non-drive side write head also runs on the existing data. Therefore, of the write heads corresponding to the two directions, the selection of the non-drive side is: Don't be wrong.

Description of Write Circuit—See FIG. 10 The configuration of the write circuit 4 is shown in FIG. The write circuit 4 includes an inverter 15, AND circuits 16, 17, 1,
8, 19, a protection determination circuit 20, a write power supply 21,
22, and write drivers 23 and 24 are provided to drive the write heads W1 and W2. FIG. 10 shows switching between two write heads.

In the figure, "WCND1" indicates a forward write head drive signal, "WCND2" indicates a reverse write head drive signal, and "PH1" and "PH2" indicate output voltages of a write power supply.

Description of a conventional example based on a time chart: see FIGS. 8, 10, and 11 In the following description, H indicates a high level and L indicates a low level. -1: The MPU 3 executes the T
At timing 1, it is confirmed that PH1ON = L and PH2ON = L.

-2: The MPU 3 has PH1ON = H, P
When H2ON = H, ALERT =
Set to H and report to MTC1. At this time, the write operation stops.

-3: Now, the initial state of the write circuit 4 (T
In 1), it is assumed that PH1ON = L and PH2ON = L and there is no abnormality. At this time, WP1 and WTENB are output by MPU3 at the timing of T2.

As a result, in the MPU 3, the write power supply 21
Alternatively, after taking a sufficient time until the write power supply 22 is determined, PH1ON, PH2ON
Inspect each signal.

-4: In the above processing, WP1 = H. If WP1 = L due to a defect, MPU3
Detects an abnormality at timing T4 based on PH2ON = H, which is a rising detection signal of the write power supply 22 that is erroneously selected.

Then, before ALERT = H,
From timing T3, WTDT (write data) is transmitted from MTC1. In this case, between the timing of T3 and the timing of T4, WC2 = L or * WC
2 = L, and the write power W2
The write current flows through. Due to this write current, the data may be partially written to the wrong track and the existing data may be destroyed.

[0021]

The above-mentioned conventional apparatus has the following problems. (1) In the parallel serpentine recording method, when a control signal of the write circuit becomes abnormal and monitoring by the MPU is delayed, writing to an incorrect track may destroy existing data.

(2) Unless measures are taken against abnormalities such as a control signal of a write circuit, the recording capacity cannot be increased by the parallel serpentine recording method or the demand for high-speed data transfer cannot be sufficiently satisfied.

SUMMARY OF THE INVENTION It is an object of the present invention to solve such a conventional problem and prevent an erroneous write head from being selected even when a control signal of a write circuit is defective, and to prevent destruction of existing data.

[0024]

FIG. 1 is an explanatory view of the principle of the present invention. In FIG. 1, the same components as those in FIGS. 8 to 11 are denoted by the same reference numerals. 38 is a forward tape motion discrimination /
A latch circuit, 39 is a reverse tape operation discrimination / latch circuit, and 40 is a tachometer.

The present invention has the following configuration in order to solve the above problems. (1) Based on the instruction from the host device (MTC), tape
Control to switch the vehicle between forward and reverse directions
Control means (for example, MPU3) and tape running state detection
(E.g., a tachometer 40) , at least two write heads W1 and W2 corresponding to the tape running direction, and a write circuit 4 for driving the write heads W1 and W2. depending on, perform the switching of the write head W1, W2, on the tape, the magnetic tape apparatus for recording data divided into a plurality of blocks, the output of the traveling state detection means
Captures, and detecting means for detecting the forward operation of the tape, a first holding means for holding the detection information of the forward operation, takes in the output of the running state detection means,
Detecting means for detecting reverse operation of the tape; and second holding means for holding detection information of the reverse operation, wherein the write circuit holds the first and second holding means. The switching of the write head is performed based on the detection information.

(2) In the above configuration (1), the light
The circuit 4 supplies power to each of the write heads W1 and W2.
A plurality of write power supplies 21 and 22,
Based on the information held by the means and the second holding means.
The power sources 21 and 22 are selectively driven.

(3) At least two write heads W1 and W2 corresponding to the tape running direction, a write circuit 4 for driving each of the write heads W1 and W2, a processor 3 for controlling the same, and a running state Tachometer output F for detection
File reel motor 8 having TACA and FTACB
And a method for switching the write heads W1 and W2 in accordance with the tape running direction, and switching the write heads in a write circuit of a magnetic tape device for recording data on a tape. The outputs FTACA and FTACB are taken in, the tape operation in the forward direction or the tape operation in the reverse direction is detected from the tachometer output, and the detection information is latched. The latched detection information and the processor 3 The write circuit 4 is switched based on the control signal, and the write heads W1 and W2 are selected.

[0028]

The operation of the present invention based on the above configuration will be described with reference to FIG. For example, when traveling in the forward direction (light head W
The processing when an abnormality occurs at the time of (selection of 1) is as follows.

-1: When the MPU 3 decodes the write command from the command from the higher-level device, the MPU 3
H, WP1 = H are set. Then, the tape running control is started. In this case, it is assumed that WP1 = L due to a circuit abnormality.

-2: When the tape running is started, the tachometer 40 linked with the file reel motor 8 generates FTACA and FTACB. -3: If the running direction of the tape is stable, if there is no abnormality described above, WCND1 = H, but since WP1 = L,
WCND1 = L remains. Also, because it is running in the forward direction,
WCND2 = L.

As a result, the write power supplies 21 and 22 are not driven, and PH1ON = L and PH2ON = L. -4: The MPU 3 takes sufficient time for the write power supplies 21 and 22 to rise, and sets the PH1ON and PH2ON.
And WP1 = H.

-5: In this comparison, when WP1 = H, PH1ON = H and PH2 = L are normal, but PH
Since 1ON = L and PH2ON = L, MPU3
ALERT = H is set for C1 as an interrupt. That is, an abnormality report is sent to the host device.

-6: HOST DAT is WRITE DAT
Cancel the transfer of A. In this case, the processing is delayed and W
Even if TDT (write data) is generated, the write power supply 2
1 and 22 are not driven and the WTDT itself is also in WCN
Since D1 = L and WCND2 = L, and gated,
It is not supplied to the write driver in the write circuit 4.

If the control procedure as described above and monitoring of PH1ON and PH2ON by the MPU 3 are performed, existing data on the tape in the opposite direction (opposite direction) can be destroyed even if the control signal of the write circuit becomes abnormal. There is no.

[0035]

Embodiments of the present invention will be described below with reference to the drawings. 2 to 7 are views showing an embodiment of the present invention. In FIGS. 2 to 7, the same components as those in FIGS. 1 and 8 to 11 are denoted by the same reference numerals. Also, the same signals as those in the above-described conventional example are denoted by the same reference numerals.

Further, 30 is a comparator, 31, 32,
33 is an AND circuit, 34 and 35 are inverters, 36 and 3
Reference numeral 7 denotes a D-FF (D-type flip-flop). In the following description, H indicates a high level and L indicates a low level.

This embodiment is similar to the above-mentioned conventional example.
This is an example of a magnetic tape subsystem employing a parallel serpentine recording method, and will be described in detail below. : Description of Magnetic Tape Subsystem ... See FIG. 2 As shown in FIG. 2, the magnetic tape subsystem of this embodiment is composed of MTC1 and MTU2, and MTU2 includes MPU3, write circuit 4, and read. Circuit 5, servo circuit 6, machine reel motor 7, file reel motor 8, machine reel 9, file reel 10, head 11
And so on. Since these configurations are the same as those of the conventional example shown in FIG.

In this embodiment, the tachometer provided on the file reel motor 8 and the write circuit 4 are connected to each other, and the output signals FTACA and FT of the tachometer are connected.
ACB (two-phase tacho pulse) is configured to be input to the write circuit 4. The internal configuration of the write circuit 4 is as follows.

Description of Write Circuit--See FIG. 3 The configuration of the write circuit 4 is shown in FIG. The write circuit 4 includes direction discriminating circuits 26 and 27, counters 28,
9, inverter 15, AND circuits 16, 17, 18, 1
9, a protection determination circuit 20, write power supplies 21, 22,
Write drivers 23 and 24 are provided, and the write head W
1. Drive W2. FIG. 3 shows a circuit for switching between two write heads.

In the above configuration, the direction determining circuit 26,
The counter 28 constitutes a circuit for detecting and latching a forward tape operation, that is, a forward tape operation judging / latch circuit 38 (see FIG. 1). The direction judging circuit 27 and the counter 29 A circuit for detecting and latching a reverse tape operation, that is, a reverse tape operation determining / latch circuit 39 (see FIG. 1) is formed.

In this case, the tachometer output signal FTAC
A and FTACB (two-phase tacho pulses) are input to the direction discriminating circuits 26 and 27, respectively. When the tape runs in the forward direction, the phase of FTACA is advanced by 90 ° from that of FTACB.
The running direction of the tape is determined from the phase difference.

The discrimination result of the tape running direction by the direction discriminating circuits 26 and 27 is counted by counters 28 and 29, and its output is fed back to the direction discriminating circuits 26 and 27 and latched.
7 is output.

WP1 (write head selection signal) is WP
When 1 = H, the write head in the tape forward direction is selected, and when WP1 = L, the write head in the tape reverse direction is selected.

Further, PRTCT is a signal for setting the write prohibition of the tape. When PRTCT = H, writing to the tape cannot be performed. The protection determination circuit 20 monitors the protection state of the tape cartridge,
This is to remove the influence of disturbance.

: Tape running in the forward direction (write head W1)
Description of the operation at the time of selection) (operation at the time of normal operation): see FIG. 4 A time chart at the time of normal running of the tape (selection of the write head W1) (operation at the time of normal operation) is shown in FIG.

-1: timing T1 in FIG.
And the write command is DATA (data) from MTC1.
When sent above, the MPU 3 recognizes this. MTU2
Sends state S to MTC1 on DATA.

At this time, PRTCT = H, PH1ON =
H, if PH2ON = H, the information is:
Since it is sent to MTC1 in state S, WRITE DA
TA does not ride on DATA. In this case, WRITE
The DATA portion is L (in the figure, it is also indicated by a dotted line).

At this time, in MTU2, WTENB
= L (indicated by a dotted line in the figure). -2: PRTCT = L, PH1ON = L, and P
When the condition of H2ON = L is satisfied (only in this condition), the write operation is executed.

-3: At the time of write operation, MTU2
The write command is decoded from the command (CMD) on DATA, and the state S is put on DATA at timing T2, and at the same time, the setting of WTENB = H and WP1 = H and the tape running control are started.

-4: When the tape running is started, the tachometer linked to the file reel motor 8 outputs F
TACA and FTACB occur. When the tape running is stabilized in one direction, the counter 28 is latched, and the write condition WCND1 = H is determined.

As a result, the write power supply 21 is driven, and P
H1 (output voltage) rises and PH1ON = H is output. -5: At timing T3, the MPU 3 checks PH1ON and PH2ON against the condition of WP1 = H.

-6: In this case, when WP1 = H, PH
Since 1ON = H and PH2ON = L are normal, MPU
3 does not interrupt MTC1 abnormally, and ALERT
= L.

-7: MTC1 is WRIT on DATA
When the transfer of E DATA is started, WT
Processed to DT (write data), WC1 = L or *
WC1 = L, and data is written on the tape.

: Running in the reverse direction of the tape (write head W2
Description of the operation at the time of (selection) (normal operation) ... see FIG. 5 FIG. 5 shows a time chart at the time of tape reverse running (write head W2 selection) (normal operation).

-1: In FIG. 5, when WTENB = H and WP1 = L at the timing T2 and the start of the tape running control, the counter 29 is latched based on the phase relation between FTACA and FTACB, and the write condition WCND
2 = H is determined.

-2: As a result, the write power supply 22 is driven, PH2 rises, and PH2ON = H is output. -3: At timing T3, the MPU 3 checks PH1ON and PH2ON against the condition of WP1 = L.

-4: In this case, when WP1 = L, PH
Since 1ON = L and PH2ON = H are normal, MPU3
Does not interrupt MTC1 abnormally, and ALERT =
It remains at L.

-5: MTC1 is WRIT on DATA
When the transfer of E DATA is started, WT
Processed into DT, WC2 = L or * WC2 = L,
Data is written on the tape.

: Running in the tape forward direction (write head W1)
Description of the operation at the time of selection) (operation at the time of abnormality) ... see FIG. 6 FIG. 6 shows a time chart at the time of tape forward running (selection of the write head W1) (operation at the time of abnormality).

-1: In the MTU2, the MPU3 receives the command (CMD) on DATA at the timing T1.
The write instruction is decoded and the state S is put on DATA at timing T2, and at the same time, WTNB = H and WP1 =
H is set, and the tape running control is started. In this case, it is assumed that WP1 = L due to a circuit abnormality.

-2: When the tape running is started, the tachometer linked to the file reel motor 8 sends the FT
ACA and FTACB occur. -3: When the running direction of the tape is stabilized, the counter 28
Is latched, but since WP1 = L, WCND1 = L
Remains. Since the counter 29 is latched at H only when the tape runs in the reverse direction, WCND2 = L.

As a result, the write power supplies 21 and 22 are not driven, PH1 and PH2 do not rise, and PH1ON =
L, PH2ON = L remains. -4: The MPU 3 takes sufficient time for the write power supplies 21 and 22 to rise, and at timing T3,
N and PH2ON are checked against the condition of WP1 = H.

-5: In this collation, when WP1 = H, PH1ON = H and PH2 = L, which are normal.
Since 1ON = L and PH2ON = L, MPU3
ALERT = H is set for C1 as an interrupt.

-6: MTC1 transmits WRI on DATA
Cancel the transfer of TE DATA. In this case, even if the WTDT is generated before the timing T4 due to the delay of the processing, the write power supplies 21 and 22 are not driven, and the WTDT is not generated.
Since it is also gated that WCND1 = L and WCND2 = L, it is not supplied to the write drivers 23 and 24. Therefore, an erroneous write operation is not performed.

The control procedure as described above, PH1ON,
By monitoring PH2ON, existing data on the tape in the opposite direction (opposite direction) will not be destroyed even if the control signal of the write circuit becomes abnormal.

Description of a specific example of the write circuit: FIG. 7
Reference A more specific circuit example of the write circuit shown in FIG.
As shown in FIG. The correspondence between FIG. 3 and FIG. 7 is as follows.

-1: The forward tape operation discriminating / latch circuit 38 is a circuit comprising the direction discriminating circuit 26 of FIG. In FIG. 7, the direction determination circuit 26
-FF (D-type flip-flop) 36, AND circuit 3
2. It is composed of an inverter 34 and the like.

-2: The reverse direction tape operation determination / latch circuit 39 is a circuit comprising the direction determination circuit 27 of FIG. In FIG. 7, the direction determination circuit 27
-FF (D-type flip-flop) 37, AND circuit 3
3. It is composed of the inverter 35 and the like.

-3: The protection judging circuit 20 comprises a comparator 30, an AND circuit 31, and the like. (Other Embodiments) Although the embodiments have been described above, the present invention can be implemented as follows.

(1) The direction discriminating circuit shown in FIG.
The protection determination circuit may be configured by a logic and an analog circuit, but may be realized by software.

(2) Even when there are more than two write heads, the present invention can be implemented in the same manner as in the above embodiment.

[0072]

As described above, the present invention has the following effects. (1) When the control signal of the write circuit becomes abnormal, the MPU
Even if the monitoring is delayed, there will be no accidental writing. Therefore, destruction of existing data can be completely prevented.

(2) Data can be recorded by the parallel serpentine method without destroying existing data. Therefore, double track data can be recorded in one cartridge, so that the storage capacity can be increased.

(3) Without moving the write head,
Data can be recorded while the write head is electrically switched. Therefore, high-speed data transfer becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a configuration diagram of a magnetic tape subsystem according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a write circuit according to an embodiment of the present invention.

FIG. 4 shows a tape running in a forward direction (W) in an embodiment of the present invention.
It is a time chart at the time of (1 selection) (normal time).

FIG. 5 shows a tape running in the reverse direction (W
It is a time chart at the time of (2 selection) (normal time).

FIG. 6 shows the tape running in the forward direction (W
It is a time chart at the time of (1 selection) (at the time of abnormality).

FIG. 7 is a specific example of a write circuit according to an embodiment of the present invention.

FIG. 8 is a configuration diagram of a conventional magnetic tape subsystem.

FIG. 9 is an explanatory diagram of a parallel serpentine recording method.

FIG. 10 is a configuration diagram of a conventional write circuit.

FIG. 11 is a time chart of a conventional example.

[Explanation of symbols]

 3 MPU 4 Write circuit 8 File reel motor 21, 22 Write power supply 38 Forward tape motion discrimination / latch circuit 39 Reverse tape motion discrimination / latch circuit 40 Tachometer FTACA, FTACB Tachometer output signal WP1 Write head selection signal W1, W2 Write head PH1ON, PH2ON Power supply inspection signal WTENB Write enable signal WTDT Write data WCND1 Forward write head drive signal WCND2 Reverse write head drive signal

Claims (3)

(57) [Claims] 1. Tapes are sequentially read based on an instruction from a host device.
The control hand that controls the vehicle to run while switching in the opposite direction
A step, a running state detecting means for detecting a running state of the tape, at least two write heads corresponding to the running direction of the tape, and a write circuit for driving the write head; In a magnetic tape device for switching the write head and recording data divided into a plurality of blocks on a tape, a detection detecting a forward operation of the tape by capturing an output of the running state detecting means. Means, first holding means for holding the detection information of the forward motion, detection means for receiving an output of the running state detecting means to detect a reverse motion of the tape, and detection of the reverse motion. And a second holding unit for holding information, wherein the write circuit is configured to control the write head based on detection information held by the first and second holding units. Performing the switching, the magnetic tape apparatus according to claim. 2. The write circuit according to claim 1, further comprising a plurality of write power supplies for supplying power to each of the write heads, and selectively selecting the write power based on information held in the first holding means and the second holding means. The magnetic tape device according to claim 1, wherein the magnetic tape device is driven. 3. The apparatus according to claim 2, wherein at least two corresponding to the tape running direction are provided.
Write heads, a write circuit for driving each of the write heads, a processor for controlling the write heads, and a file reel motor having a tachometer output for detecting a running state. And a write head switching method in a write circuit of a magnetic tape device for recording data on a tape, wherein the tachometer output is taken into the write circuit, and a tape operation in a forward direction or a reverse direction is performed from the tachometer output. Detecting the tape operation, latching the detection information, switching the write circuit based on the latched detection information and a control signal from the processor, and selecting a write head. A write head switching method in a write circuit of a magnetic tape device.