JPS6038708A - Automatic control system for reading gain of magnetic tape - Google Patents

Abstract

PURPOSE:To improve the reliability of the titled system by so controlling as deciding that control is exercised without error as long as the reading gain control succeeds at a certain tape driving speed although said gain control fails at another driving speed. CONSTITUTION:Flag bits 403 and 404 of high and low speeds respectively are read and tested by a control part 10 for all tracks of a memory map 40. It is decided that the control fails with both speeds when the bits 403 and 404 of all tracks are set at 1. Then an error is reported to an upper rank device. If 1 is not detected with either one of both speeds, the corresponding speed is set to a control register 41 from the part 10 as a speed system having a normal end. Then a reel motor is driven through a motor servo control circuit 42 to read a normal data block.

Description

Detailed Description of the Invention (al) Technical Field of the Invention The present invention relates to a magnetic tape device which is an external storage device for an information processing device, and particularly in a magnetic tape device having a plurality of tape running speeds. This invention relates to an automatic read gain control method that optimizes read gain using special bursts for read gain adjustment.

(bl Technology background) A magnetic tape device, which is an external storage device for an information processing system, consists of two horizontal motors, two capstan motors, and a vacuum column (or tension arm).
In order to keep the running speed of the tape constant, a high-precision servo mechanism using, for example, the vacuum column described above is required, which poses a problem of increasing costs.

Therefore, there is a need to construct a low-cost magnetic tape device that has a high running speed, and one known example is a magnetic tape device that has two tape speeds.

This is composed of two reel motors and a pinch roller corresponding to each reel, and the rotational speed of the pinch rollers is detected to control the two reel motors. Therefore, it does not require a high-precision servo system like the conventional one, and has the characteristic of realizing a high-speed magnetic tape device at low cost.

However, in this method, the inertial mass of the reel motor is large in order to start and stop the tape running within the interblock gap (hereinafter referred to as IBG) provided between the data block and the data block. Therefore, there was a problem that it could only be operated at low speeds, and sufficient performance was not obtained.

However, even with this method, if the above IBG is not used to start and stop (this usage is called streaming mode), there is no problem once the running speed is increased, so the tape speed is sufficiently high. Therefore, when constructing a high-performance magnetic tape device using this method, a magnetic tape device with two types of tape running speeds is required, taking into account the use of start-stop using the IBG. In this case, even a cheap running device can achieve high barf performance.

In such a magnetic tape device having two tape running systems, high density (for example, 6250 lines/l) (hereinafter referred to as R
When processing a medium with a recording density of
It is necessary to switch and adjust it to be optimal at each speed.

On the other hand, in high-density recording magnetic tape media, a special burst for recording density recognition is written at the write start point (hereinafter referred to as BOT), and immediately after that, a special burst for read gain adjustment (hereinafter referred to as 5AGC burst) is written. hand,
This 5AGC burst (for example, data of all "1") is read at regular intervals, amplified by the above amplifier, and compared with the specified voltage (SV). If it is less than the specified value (SV), the gain counter is set to +I. The specified value (SV
) When an output of more than 100% is obtained, the read gain automatic adjustment mechanism sets the value of the gain counter to the gain at that tape running speed.

Note that the output of the read head is proportional to the tape running speed if the recording density (that is, magnetic flux density) is the same, so in a magnetic tape device with two types of running systems,
If the gain at one running speed can be obtained, the gain at other running speeds can be obtained by simply switching the gain of the amplifier, but since the gain of the amplifier generally has non-linear characteristics, 2 It is necessary to perform the same automatic gain adjustment as above at two driving speeds.

In the present invention, even if the gain counter has an Ohnoy flow (indicating the maximum gain of the amplifier), the read output remains at the specified value (
SV) is involved in what to do if the value is not exceeded.

(C) Conventional technology and problems Magnetic tapes for information exchange have multiple recording densities.
Especially for the recording density of 6250 RPI, a special burst for recording density recognition 1 and a 5AGC burst are written in the BOT immediately after that.

Since conventional magnetic tape devices operate at a single running speed, when reading the above 5 AGC bursts and automatically controlling the amplifier gain, the gain is increased step by step from the lowest value A to obtain the optimum value. However, if there is a trunk for which the reading output is not sufficient even if the gain is set to the maximum value, an error is reported to the host device G.

Therefore, if the conventional method is adopted in a magnetic tape device that has multiple running speeds, even if reading gain adjustment is successful at a certain running speed, if read gain adjustment fails at other running speeds, an error will always occur. As a result, the only option was to interrupt further information processing.

(dl Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention provides a magnetic tape device having a plurality of running speeds.
Even if the automatic gain adjustment by burst fails, it succeeds at another speed, or even if it fails at a certain trunk and a certain travel speed, the above automatic gain adjustment succeeds at multiple travel speeds for a specific trunk. In this case, without error,
The purpose of this is to provide a method that eliminates processing interruptions.

(e) Structure and object of the invention, according to the invention: In a magnetic tape device for information exchange, which is equipped with a running speed and has a function of optimizing the above-mentioned automatic read gain adjustment at each of a plurality of speeds, at a certain running speed at a certain running speed. Even if the reading gain adjustment fails, if the reading gain adjustment is successful at a different traveling speed, the reading gain adjustment of the device is not determined to be a failure, but means is provided for setting the traveling speed at which the automatic reading adjustment was successful, A method of controlling the system so that information processing continues at the set travel speed from then on.

(21 (In the magnetic tape read gain automatic control method described in item 11, even if there is a track for which the automatic adjustment cannot be performed at a certain traveling speed, it is not considered an error, and the automatic # circumference adjustment is performed at a plurality of traveling speeds in a certain trunk. If you can,
A means for calculating the ratio of gains at the plurality of traveling speeds is provided, and the gain value at the speed at which Masatomi ended at the speed at which automatic adjustment failed at a certain traveling speed is multiplied by the above ratio. A method in which the gain is set as the gain at the traveling speed, and thereafter the set gain is used as the gain at the aforementioned failed traveling speed of each truck.

5 at a certain speed.
Even if automatic gain adjustment using AGC burst fails, it may succeed at another speed, or even if it fails at a certain running speed on a certain truck, the above automatic gain adjustment may succeed at multiple running speeds on a specific truck. In this case, there is an advantage that no error occurs and processing is not interrupted.

(f) Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an example of information written near the writing start point (BOT) on a magnetic tape medium for information exchange, where 1 is a magnetic tape medium, 11 is a recording density indicator, and 1
2 is a BOT marker, 13 is a read gain adjustment burst (ie, 5AGC burst), and 14 is a data block.

Here, the 5th AGC berth 3 is the burst data necessary for automatic read gain adjustment related to the present invention, and the 2nd
The operation of the automatic gain adjustment mechanism will be explained with reference to figures.

In Figure 2, 2 is a readhead, 3 is a preamplifier (
PAMP), 4 is an amplifier (AMP), and 5 is a demodulation circuit, which demodulates the read output of the data block 14 and transfers it to the host device. Reference numeral 6 denotes a comparator (C) which, when a read signal greater than a specified voltage (SV) is input, creates a pulse signal that maintains a constant voltage for a portion greater than the specified voltage (SV).

Reference numeral 7 denotes a pulse generation circuit which logically differentiates the rise and fall of the digital signal output from the comparator (C) 6 to create a series of pulse signals. Reference numeral 8 denotes a recording signal detection circuit (DET), which detects the presence or absence of the above-mentioned pulse signal, and detects the presence or absence of the pulse signal at a certain timing.
When the pulse signal is not obtained, it means that there is not enough gain, so the control section 10 recognizes this and operates to give the gain counter (GC) 9 an incremented value. Reference numeral 9 denotes the gain counter (GC), which is composed of, for example, 4 bits, and by sending a count value to an amplifier (8MP) 4, a gain corresponding to the value can be obtained.

Now, as the information exchange magnetic tape medium 1 shown in FIG. The read output is inputted to a comparator (C) 6 through an amplifier (8Ml') 4. (However, when the running position of the magnetic tape medium for information exchange is at the head position of the 5AGC burst, the gain counter (GC) 9 is controlled by the control unit 10 so that the initial value is set to 0.) The comparator (C) 6 has the peak value of the read output voltage [converted output value of the amplifier (AMP) 4] corresponding to the recording density and running speed of the magnetic tape for magnetic exchange to be used - 90% value of the peak value. is input as the specified value (SV) at that time, and is compared with the read output of the amplifier (AMP) 4. If the read output value is smaller than the specified value (SV), nothing is output, but the reading When the output value is larger than the specified value (SV), a digital signal of a constant voltage is output for the oversized portion.

This digital signal is subjected to logical differentiation of rising and falling edges in a pulse forming circuit 7, and is sent to the next recording signal detection circuit (DET) 8 as a series of pulse trains.

If the pulse train is not detected in a specific timing period, the recording signal detection circuit (DET) 8 determines that the read output from the amplifier (A?IP) 4 is smaller than the specified value (SV), and outputs a zero signal. Control part 1
Send to 0. When the control unit 10 detects the zero signal, it determines that the gain of the amplifier (AMP) 4 is insufficient, and in order to increase the gain of the amplifier (AMP) 4, a count amplifier is sent to the gain counter (GC) 9. It operates to set the specified value. A gain counter (GC) 9 converts this +1 counter value to an amplifier (AMP) 4.
The amplifier (AMP) 4 sends out the read output to the controller (C) 6 with this +1 gain. Thereafter, the recording signal detection circuit (DET) 8 repeats the same operation at fixed timings within the range of the 5AGC burst 13 until the pulse train is detected.

If the recording signal detection circuit (DET) 8 detects the pulse train, the gain counter (DET) at that time
The gain of the amplifier (AMP) 4 specified by GC) 9 has sufficient gain to read the information exchange magnetic tape medium.

The above operation is an outline of the automatic halftone adjustment operation of the read gain.

Here, when the gain counter (GC) 9 overflows, it means that even if the gain of the amplifier (AMP) 4 is set to the maximum, the read output of the amplifier (AMP) 4 cannot be obtained above the specified value. This indicates at least one error condition.

The present invention relates to a method for reporting an error to a host device when the gain counter (GC) 9 overflows.

FIG. 3 shows a flowchart of the operation flow when the reading gain is automatically opened and adjusted when the present invention is implemented. The present invention provides steps 29 to 32 and steps 33 to 3 in this flowchart.
This applies to operation 5.

Hereinafter, each step in FIG. 3 will be briefly explained with reference to FIG. 2.

This embodiment shows the case of a magnetic tape device having two tape running speeds. In this case, the tape running speed can be freely specified by software.

Step 20: Tape specified in software.

Check whether the vehicle is traveling at high or low speed.

Then, when the speed is high, the process moves to the next step knob 21, but when the speed is low, the process moves to step 22.

Step 21: Set the tape running speed to a low speed.

Step 22: Set the tape running speed to high speed.

Step 23: For each track of the magnetic tape medium, the read gain is automatically adjusted in parallel as explained in FIG.
The gain value set in 1 flow (auto1 flow display) is stored in memory.

In this case, the gain counter (GC) 9 is scooted from 0 = 0, and at regular timings, for all of the 5th AGC parse 3, the recording signal detection circuit (DET'') 8 is sequentially scanned for tracks where there is no output signal. Step 24 operates to set the stepped value in gain counter (GC) 9: In this step, the traveling speed specified in step 20 is compared with the currently set traveling speed, and if they match. If there is, move on to the next step.
If they do not match, jump to step 25.

Step 25: Rewind the magnetic tape medium to BOT.

Step 26: Set the travel speed specified by the software, and return to step 23 to automatically adjust the reading gain at that speed.

Step 27: Here, it is checked whether the value set in the gain counter (GC) 9 has overflowed. If there is no overflow, it means that as a result of the gain adjustment in step 23, a read output higher than the specified voltage (SV) was obtained within the gain obtained by the amplifier (AMP) 4, and the process was completed normally. With this, the process moves to step 28.

If overflow occurs, the amplifier (AMP)
This means that even if the read signal was amplified with a maximum gain of 4, the output of the specified value could not be obtained.
Jump to step 29° or 33).

Step 28: In case of normal termination, proceed to processing of the subsequent data block. The data block transfer route at this time is the route from the demodulation circuit 5 to the host device in FIG.

Below, the operation when the present invention is implemented will be explained. That is, step 29: For all tracks of the magnetic tape medium,
At two travel speeds, gain counter (GC) 9
Check whether the value set to overflows.

If, at both speeds, on either track,
If there is an overflow, the magnetic tape medium cannot be used, and the process moves to step 30 to report an error to the host device.

Step 30: Report the error to the host device.

Step 31: However, if all trunks have completed normally at one of the two travel speeds, set that speed to the travel speed at the time of data block processing for lightning, and proceed to the next step. Move to.

Step 32: Proceed to processing subsequent data blocks.

Step 33: The operations after this step represent another embodiment of the present invention. First, for each trunk of the magnetic tape medium, it is possible to check whether or not there is a trunk that has completed normally at two running speeds.

If the track does not exist, the magnetic tape medium cannot be used, so the process jumps to step 30 to report an error to the host device.

If there is at least one track that has completed normally at two speeds, the process moves to the next step 34.

Step 34: Successfully completed 1-rack at two speeds (
However, if there are a plurality of such trunks, in step 33, the ratio of the gain values set in the gain counter (GC) 9 corresponding to both speeds is calculated for the trunk detected first.

Step 35: For each track other than the track that successfully completed at two speeds, set the gain obtained by multiplying the gain value of the normally completed speed side by the above ratio as the gain for the failed speed side, Proceed to step 32. The above ratios are reciprocals when multiplied by the normally completed high speed side and when multiplied by the low speed side.

If there is a track in each of the above trunks that does not complete normally at any speed, that magnetic tape medium cannot be used, so it is necessary to skip to step 30 to report an error. be.

That's all for steps 29-32. Or to summarize the present invention explained in steps 33 to 35, one of them is that in a magnetic tape device having two running speeds, even if automatic gain adjustment by 5AGC burst fails at one speed, it succeeds at another speed. If so, it is not determined as an error, and from now on, information processing on the magnetic tape medium is performed only at the successful running speed. The other is that automatic gain adjustment using 5AGC bursts is performed on certain trunks with 2
If the autotuning is successful at one speed, calculate the ratio of the gains at both speeds, and distribute it proportionally to the other trunks for which autotuning failed at either speed to match the gain at the speed at which the trunk failed to tune. It is something to do.

FIG. 4 is a block diagram schematically showing a magnetic tape device (having two running speeds) in which the present invention is implemented, and 1 to 1o are the same as those explained in FIG. 2. . 4o is a memory map necessary for implementing the present invention, in which gain information for controlling the amplifier (^MP) 4 for nine trunks on the magnetic tape medium is stored, and 401 and 402 are for high-speed, high-speed, When the gain data to be set in the gain counter (GC) 9 is accumulated during low speed driving, and the detection output from the recording signal detection circuit (DET) 8 cannot be obtained at regular intervals, the control unit 1o The gain value of the trunk is read out through the multiplexer 43, and the controller 1o performs +1 calculation, and the value is sent to the gain counter (GC) 9 to adjust the gain of the amplifier (AMP) 4. At the same time, the gain value at that time is stored in the corresponding area 4o of the memory map 4o.
1°402. 403.4
04 is a flag bit for each trunk that is turned off when sufficient gain is obtained as a result of automatic read gain adjustment during high speed and low speed driving, and turned on when gain adjustment fails.

Reference numeral 41 denotes a control register (REG) that provides control information to the motor servo control circuit 42, such as a running speed instruction, a motor start instruction, and a rewind instruction. The motor servo control circuit 42 is a control circuit that applies a necessary rotation speed to the reel motor while detecting the rotation speed of the pinch roller, and runs the magnetic tape medium 1 at a high speed or a low speed. 43 is a multiplexer which connects a recording signal detection circuit (DIET) according to the address data from the control unit IO;8. Memory map 40. It is controlled to switch input signals from a control register (REG) 41.

The control unit 10 reads a command from a control memory (not shown), and according to the command, controls the recording signal detection circuit (DET).
> 8. Memory map 40. Control register (1?EG
) 41, this is also calculated by an arithmetic circuit (not shown), and the result is sent to the output data bus, which is then sent to a gain counter (GC) 9 [ultimately an amplifier (AMP') 4 ] , control register (I
IUG) 41 [Ultimately a magnetic tape running system]
.

It operates to control the memory map 40.

First, when the power is turned on, all zero data is sent from the output data bus along with an address specifying the memory map 40 from the control unit 10, and the memory map 40 is completely cleared.
Subsequently, a gain counter (GC) 9 is designated, and an initial value of 0 is sent and cented.

Next, the control register (REG) 41 is specified, and the third
According to the flow explained in the figure, the running speed of the magnetic tape is set (steps 21 and 22), the reel motor is driven according to that value, the magnetic tape medium 1 starts running, and the 5AGC burst 13 is sent to the lead by the read speed 2. be read.

At each running speed, the output value of the recording signal detection circuit (DBT) 8 is changed to the multiplexer 43.
If no output signal is obtained, it means that the gain previously set in the gain counter (GC) 9 is insufficient, and the control unit 0 outputs the corresponding track in the memory map 40. The value is read out, +1 is added to that value, and the value is added to the gain counter (GC) 9 again, and is also stored in the corresponding area of the memory map 40. (Step 23) If the gain value of the relevant trunk is read from the memory map 40 and incremented by +1 in the control unit 10, an overflow is detected [condition code (CC) as a result of executing the command from the control memory]. ], the above automatic read gain adjustment is said to have failed, and the flag bits 403 and 404 of the memory map 40 are set on (step 27), and in the subsequent control method of the present magnetic tape device, the present invention is It is necessary to implement the following.

Therefore, first, the operations of steps 29 to 32 explained in FIG. 3 will be explained with reference to this drawing.

In this step, the control unit 10 reads the flag bits 403 and 404 for high speed and low speed for all trunks in the memory map 40,
be tested. (Step 29) Then, flags 403 and 404 of all trunks for both speeds are set to "1", indicating a failure in adjustment of both speeds, and it is necessary to report an error to the host device. (Step 30) However, if ■'' is not detected at either high speed or low speed, that speed is assumed to be the speed system in which the positive current has ended.
The control unit 10 sets the control register (REG) 41 (step 31), and the motor servo control circuit 42,
It is controlled to drive the reel motor and proceed to reading the regular data block 14. (Step 32) Next, the operations of steps 33 to 35 in FIG. 3 will be explained.

In this case, in the control unit 10, the memory map 7
The gain value of trunk #0 is read out sequentially from the flag bit, and a trunk for which reading gain automatic adjustment at two speeds has been successfully completed is searched (ie, a trunk with flag focus - 0).

If the trunk cannot be searched, the present invention cannot be carried out, so the control section 10 operates to report an error to the higher-level device. (Step 3
3) In the above search, if the flag bits 403 and 404 at two speeds in a certain trunk are logic "0", it means that automatic adjustment of read gain at two speeds has been successful in that trunk. , the high speed and low speed gain values 401 and 402 of the trunk are read, a calculation unit (not shown) in the control unit 10 calculates a ratio, and the ratio is stored in an internal register (not shown). (Step 34) Then, for other 1-ranks, flagvi-nod=0
The value obtained by multiplying the gain value on the side of - Set in the relevant area of the knob 40. Excluding trucks that successfully completed this process at both speeds above,
Perform this for all tracks. (Step 35) However, in this processing process, if there is a trunk with flag bits 403 and 404 = 1 at both speeds, the proportional allocation process described above cannot be performed, so the control unit 10 sends an error report to the host device. Make sure to do the following. (Step 35) The gain counter (GC) 9 is controlled by the control register (GC) 9 through the multiplexer 43 when the reading gain is automatically adjusted at high speed and low speed.
This is done by reading the data of REG) 41, knowing the running speed at that time, and reading the gain value of the speed from the memory map 4o.

In a magnetic tape device that has multiple running speeds, even if automatic gain adjustment using 5AGC burst fails at a certain speed, it is successful at another speed, and even if it fails at a certain trunk and a certain running speed, the specific If the automatic gain adjustment described above is successful at a plurality of running speeds in the trunk, it is controlled so as not to cause an error, which has the effect of making it possible to construct a highly reliable magnetic tape device.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of information written near the writing start point of a magnetic tape medium for information exchange, FIG. 2 is a diagram explaining the automatic gain adjustment mechanism, and FIG. FIG. 4 is a block diagram showing a magnetic tape device embodying the present invention. In the drawing, ■ is a magnetic tape medium, 13 is a read gain adjustment burst (SAGC burst), 14 is a data block, 2 is a read head, and 3 is a preamplifier (PAM).
P), 4 is an amplifier (8 MP), 6 is a comparator (C), 7 is a pulse generation circuit, 8 is a recording signal detection circuit (DET), 9 is a gain counter (GC)
. 10 is a control unit, 20 to 35 are when the present invention is implemented,
Each step of the operation flow during read gain automatic adjustment, 4
0 is the memory map, 401 and 402 are the gain values, 40
3. 404 is a flag bit, 41 is a control register (RE
G). 42 is a motor servo control circuit, and 43 is a multiplexer.
, SV indicate the specified voltage of the comparator (C) 6, respectively. Tokukai HGO-38708 (8)

Claims (1)

[Claims] (1) A magnetic tape device for information exchange, which has a function of automatically optimizing the reading gain by means of a special burst on the medium, and which has multiple tape running speeds, and which has the function of automatically optimizing the reading gain by using a special burst on the medium. In a magnetic tape device for information exchange that has the function of optimizing each speed at multiple speeds,
Even if reading gain adjustment fails at a certain traveling speed for all trucks, if reading gain adjustment is successful at another traveling speed, it is not considered a reading gain adjustment failure of the device,
The automatic reading gain control system is characterized in that means is provided for setting a traveling speed at which the automatic reading adjustment is successful, and the information processing is continued at the set traveling speed thereafter. Even if there is a trunk for which automatic adjustment cannot be performed, it is not treated as an error, but if the automatic adjustment is possible at a plurality of traveling speeds for a certain trunk, a means is provided to calculate the ratio of the gain at the plurality of traveling speeds, and at a certain traveling speed. Multiply the gain value of the speed at which automatic adjustment failed for the speed at which the automatic adjustment failed by the above ratio,
An automatic magnetic tape read gain control method characterized in that the gain is set as the gain at the failed running speed, and thereafter the set gain is used as the gain for each track at the failed running speed.