JPH0520732A - Magnetic tape device with medium discriminating function - Google Patents

Abstract

PURPOSE:To provide a means for recognizing a magnetic tape medium by directly detecting the characteristic of the medium. CONSTITUTION:The device possesses a write circuit 12 for writing a magnetic tape medium 11 and a read circuit 13 for reading the magnetic tape medium 11. Furthermore, the device is provided with a medium characteristic measuring circuit 21 for measuring a characteristic of the magnetic tape medium 11, a medium discriminating part 22 for discriminating the magnetic tape medium 11 by an output of the medium characteristic measuring circuit 21 and a write condition setting part 23 for setting a write condition for the write circuit 12. Then, the characteristic of the magnetic tape medium 11 is measured, and from this result, this magnetic tape medium is discriminated, and then the write condition is set so as to perform a write operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape device having a medium identifying function.

[0002]

2. Description of the Related Art In a magnetic tape device, there are a plurality of media having different write densities due to different medium characteristics. When writing to a magnetic tape medium, the difference between the media is detected to perform a predetermined writing. / Set the scanning conditions,
It must be written / read.

In a conventional apparatus, there is a method of recognizing a case (cassette or cartridge) for accommodating a medium by changing a part of its outer shape when the medium characteristics are different. In this case, a detection mechanism using a mechanical sensor or an optical sensor for detecting a difference in outer shape is required.

FIG. 5 is an illustration of a conventional medium recognition method. In the figure, 41 is a magnetic tape medium case for accommodating a magnetic tape medium, 42 is a hole provided for the medium identification in the magnetic tape medium case, 43 is a spring provided so that the protrusion of the switch 44 is inserted into the hole, 44 is a contact signal Q when the protrusion 45 of the switch enters the hole 42 of the magnetic tape medium case 41.
Is a switch for generating a switch, and 45 is a protrusion provided on the switch. The magnetic tape medium case 41 shown in the figure is provided with a hole 42, and the presence or absence of the hole 42 is used to recognize the medium.
If the hole 42 is present, the protrusion 45 of the switch 44 enters the hole 42, in which case the switch 44 delivers a contact signal Q.
The medium is identified by the presence or absence of the contact signal Q.

When the loading mechanism in the magnetic tape is generally complicated and there is a demand for miniaturization of the device, the provision of such a detection mechanism has been a problem in terms of space and cost. .

[0006]

Providing a mechanism for identifying a medium in the case of a magnetic tape medium in a magnetic tape device has a problem of increased space and cost.

In view of the above points, the present invention has an object to provide a means for directly detecting the characteristics of a magnetic tape medium to recognize the medium.

[0008]

The above-mentioned problems can be solved by a magnetic tape device having a medium identification function configured as follows. FIG. 1 is a principle diagram of the present invention.

In a magnetic tape device having a write circuit 12 for writing on the magnetic tape medium 11 and a read circuit 13 for reading the magnetic tape medium 11, a medium characteristic measuring circuit 21 for measuring the characteristic of the magnetic tape medium and the medium. Characteristic measurement circuit 21
Identifying section for identifying the magnetic tape medium 11 based on the output of
22 and a write condition setting unit 23 for setting the write condition of the write circuit 12, the characteristics of the magnetic tape medium are measured, the magnetic tape medium is identified from the result, and the write condition is set. Is set and writing is performed.

[0010]

The medium characteristic measuring circuit 21 measures the characteristic of the magnetic tape medium. The medium identifying unit 22 identifies the magnetic tape medium 11 based on the output of the medium characteristic measuring circuit 21.

Based on the identification result, the write condition setting unit 23 sets the write condition of the write circuit 12.

[0012]

EXAMPLE A magnetic tape medium has frequency characteristics depending on the constituent materials, and the difference between the media can be recognized by detecting the difference in the frequency characteristics.

FIG. 3 is a graph showing frequency characteristics of read outputs of the medium A and the medium B. Two frequencies close to the upper limit of the frequency characteristic are selected, writing is performed at those frequencies (f1 and f2), and the read output is measured. Then, for each medium, the ratio of the read outputs of the two frequencies is calculated. If the ratio of the read output of medium A is R _A and the ratio of the read output of medium B is R _B , then R _A = read output level of medium A at f2 / read output level of medium A at f1 R _B = It can be defined as the read output level at f2 of medium B / the read output level at f1 of medium B.

Since a large difference appears between R _A and R _B depending on the medium, it becomes possible to recognize which the medium is. FIG. 2 is a diagram showing the configuration of the embodiment of the present invention. In the figure, 11 is a magnetic tape medium for recording information, 12 is a writing circuit for writing on the magnetic tape medium 11, 13 is a reading circuit for reading the magnetic tape medium 11, 2
3 is a write condition setting unit for setting the write condition of the write circuit, 25 is a peak hold circuit for holding the peak value of the output of the read circuit 23, and 26 is A for converting the output of the peak hold circuit 25 from an analog value to a digital value. / D converter, 2
Reference numeral 1 is a medium characteristic measuring circuit composed of a peak hold circuit 25 and an A / D converter 26, 27 is a microprocessor (hereinafter abbreviated as MPU) which sets a write condition setting unit 23 and measures the medium characteristic, 28 Is a read condition setting unit for setting read conditions.

In this embodiment, the data writing for measuring the characteristics of the medium is performed before the BOT (Biginnig Of Tape) indicating the starting point of the data writing on the magnetic tape medium. Further, by writing the measurement data in advance before the write-prohibition mark is attached, the characteristic measurement can be performed even on the magnetic tape medium to which the write-prohibition mark is attached. Before the BOT, the recorded data is not recorded and may not be recorded. Therefore, this area is used for the characteristic measurement. Then, advance media inherent said comparing the measurement result with a reference value in advance gives a reference value R _A of the frequency output ratio and R _B, identifies the media. First, the writing circuit 12 writes the write data on the magnetic tape medium so that the write data frequency becomes the first frequency f1. Then, while writing data, the reading circuit 13 immediately reads by the read-after-write function. The read output is amplified by the read circuit 13, enters the peak hold circuit 25, and the peak value held in the peak hold circuit 25 is A /
The D converter 26 converts it into a digital value and measures the read output level at the first frequency f1. The MPU 27 stores the read output level. Next, the MPU 27 sets the write condition setting unit 23.
Set the second frequency f2 to. Similarly the second frequency
The ratio R of the read output level at f2 to the read output level at the first frequency f1 measured and stored is calculated, and the reference values R _A and R _{B of the} frequency output ratio given in advance are calculated. The medium can be recognized in comparison with.

As the write condition, the write frequency and the write current value are set in the write condition setting section according to the recognition result of the medium. As the read condition, the amplification factor at the time of read is set in the read condition setting unit. In this way, optimum conditions can be set for the medium.

As another embodiment, there is also a method in which the writing frequency to the medium is one and the output value at that frequency is used for recognition. There is also a method of examining the write saturation characteristic of the medium. The medium characteristic can be recognized even when the writing frequency is fixed and the writing current is changed to measure the saturation characteristic. FIG. 4 is an explanatory view of the principle of another embodiment of the present invention,
6 is a saturation characteristic curve showing the relationship between the write current and the read output of the medium. 90% of peak value of read output for saturation current A
If it is considered that the write current gives the output shown in FIG.
Is a method of identifying the difference between IwA and IwB by measuring. In this case, the write circuit needs to have a function of changing the write current according to an instruction from the MPU.

FIG. 5 is a control flowchart of the embodiment of the present invention. In step 81, loading of the magnetic tape medium is started. In step 82, the magnetic tape is advanced until it reaches the writable position. In step 83, it is determined whether or not the medium is writable. If writable, the process proceeds to step 84, and if writable, the process proceeds to step 85. In step 84, the media characteristics are measured in write mode. The measuring method at this time adopts the above-mentioned method. In step 85, the medium characteristics are measured in read mode. The measuring method is the same. When the measurement is completed, the process proceeds to step 86, the medium difference is recognized from the measurement result, and the medium is identified. The loading operation is completed by advancing the magnetic tape medium to BOT in step 87. B like this
By providing the measurement area before the OT, the magnetic tape medium can be recognized before the magnetic tape is loaded.

[0019]

As is apparent from the above description, according to the present invention, the characteristics of the magnetic tape medium can be directly detected to recognize the medium, and the writing can be performed by setting the conditions for writing the medium. There is a remarkable industrial effect.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is an explanatory diagram of the principle of the embodiment of the present invention.

FIG. 4 is an explanatory diagram of the principle of another embodiment of the present invention.

FIG. 5 is a control flowchart of the embodiment of the present invention.

FIG. 6 is an explanatory diagram of a conventional medium recognition method.

[Explanation of symbols]

11 magnetic tape medium 12 writing circuit 13 reading circuit 21 medium characteristic measuring circuit 22 medium identifying section 23 writing condition setting section 25 peak hold circuit 26 A / D converter 27 MPU 28 reading condition setting section 41 magnetic tape medium case 42 hole 43 spring 44 Switch 45 Protrusion

Claims (3)

[Claims] 1. A magnetic tape device having at least one of a write circuit (12) for writing to a magnetic tape medium (11) and a read circuit (13) for reading the magnetic tape medium (11), characterized in that: Measuring circuit for medium characteristics (21)
And a medium identifying section (22) for identifying the magnetic tape medium (11) by the output of the medium characteristic measuring circuit (21). 2. The magnetic tape device according to claim 1, further comprising a write circuit (12) for writing on the magnetic tape medium (11), wherein the write circuit is output by the medium identifying unit (22).
A magnetic tape device having a medium identification function, comprising a write condition setting unit (23) for setting the write condition of (12). 3. The magnetic tape device according to claim 1, further comprising a write circuit (12) for writing on the magnetic tape medium (11), wherein the write circuit is output by the medium identifying section (22).
A magnetic tape having a medium identifying function, comprising a write condition setting unit (23) for setting the write condition of (12) and a read condition setting unit (28) for setting the read condition of the read circuit (13). apparatus.