JPH04205971A - Abnormality detector for magnetic head - Google Patents

Abstract

PURPOSE:To surely detect the abnormality of a magnetic head by rewinding a magnetic tape up to the position where information can be read and reproducing the information, then detecting the presence or absence of the reproduced information of the magnetic tape when-the reproduced information cannot be read continuously for a prescribed period of time with the magnetic head. CONSTITUTION:A travel driving mechanism section 1 for the magnetic tape T, a control section 2 for controlling the travel driving mechanism section and a means 3 for detecting the presence or absence of the reproduced information read out with the magnetic head H are provided. The information is read by returning the magnetic tape T to the position before the information is no longer detected when the information from the magnetic tape T is not detected continuously for the prescribed period of time with the magnetic head H. The presence or absence of the reproduced information from the magnetic tape is then detected. Namely, judgment can be made that the cause for the failure in reading out the information lies in the unrecorded part of the information if there is the reproduced information at this time. Judgment can be made that the cause lies in the abnormality of the magnetic head H if there is no reproduced information. The abnormality of the magnetic head H is rapidly and exactly detected in this way.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to an abnormality detection device for a magnetic head in a magnetic tape device. The magnetic tape is rewound and played back up to the point where it is played back, and an abnormality in the magnetic head is detected based on the presence or absence of playback information from the magnetic tape.

This makes it possible to reliably detect abnormalities in the magnetic head.

[Industrial application field]

The present invention relates to an abnormality detection device for a magnetic head in a magnetic tape device, particularly a magnetic tape device such as a digital audio tape recorder (hereinafter referred to as DAT) used as an external storage device for a computer system.

[Conventional technology]

In recent years, DATs have rapidly become popular as audio signal recording and reproducing devices, and because of their large recording capacity and small size, they are attracting attention as external storage devices for computer systems, primarily for backing up computer hard disk drives.

FIG. 3 is a configuration diagram of a magnetic tape device used as external storage in a computer system, and is used to store data stored in the magnetic disk device 11 in a computer system consisting of a host computer 10 and a magnetic disk device 11, and to back up data in the event of a failure. For use, DAT
A case is shown in which a magnetic tape device 20 is used.

The main microcomputer (main microcomputer) 21 receives commands such as read/write and file search from the host computer 10 via the interface circuit 22, processes them, and performs recording, playback, and fast forwarding (or fast forward playback). ), rewind or rewind playback), and stop commands and transmit them to the microcomputer 23 that controls the traveling drive mechanism section 24 . The deck microcomputer 23 controls the traveling drive mechanism section 24 based on this command.

Additionally, the magnetic tape device 20 is provided with various circuits and memories for signal processing of information recorded on the magnetic tape, and the main microcomputer 21 also transmits this information to and from the host computer. Or omit it here.

[Invention or problem to be solved]

When the magnetic tape device 20 is unable to read information for a predetermined period of time while reproducing information from the magnetic tape,
It is determined that this is an unrecorded portion where no information has been recorded, and the process moves to the next step.

However, due to clogged magnetic heads, information may become unreadable during playback, and even in this case, there is the problem that information may be mistakenly judged to be an unrecorded area even though it has been recorded normally. Ta.

The present invention provides magnetic head abnormality detection that can quickly and accurately detect whether the cause is an unrecorded area of information or an abnormality in the magnetic head when information becomes unreadable during playback of a magnetic tape device. It is intended for equipment.

[Means to solve the problem]

In order to solve the above problems, the present invention includes a magnetic tape running drive mechanism section, a control section that controls the running drive mechanism section, and means for detecting the presence or absence of reproduction information read by a magnetic head. In preparation, when the information is not detected continuously for a predetermined period of time by the detecting means, the control section rewinds and plays the magnetic tape to a position before the information was not detected, and rewinds and reproduces the magnetic tape from the magnetic tape. The present invention is characterized in that an abnormality in the magnetic head is detected by detecting the presence or absence of reproduced information.

[Effect]

According to the present invention, when information from the magnetic tape is not continuously detected by the magnetic head for a predetermined period of time, the magnetic tape is rewound and played back to the position before information was no longer detected, and the reproduced information from the magnetic tape is Since the presence or absence of the information is detected, if there is playback information at this time, the information cannot be read (
It can be determined that the cause of the error is due to an unrecorded portion of information, and if there is no reproduced information, the cause can be determined to be due to an abnormality in the magnetic head. Therefore, an abnormality in the magnetic head can be detected quickly and accurately.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an abnormality detection device for a magnetic head according to the present invention. In the figure, 1 is a running drive mechanism section for a magnetic tape T, and 2 is a control section that controls a running drive mechanism section 31. It corresponds to the deck microcomputer 23 shown in Figure 3 and is composed of a microcomputer. Reference numeral 3 denotes an envelope detection circuit for detecting an envelope component of reproduced information read by the magnetic head H, and detects the presence or absence of reproduced information based on its output.

The control section 2 controls the running drive mechanism section 1 to perform processing such as recording, playback, fast-forward playback, rewind playback, and stop on the magnetic tape T, and also performs abnormality detection processing of the magnetic head.

In this embodiment as well, various circuits for signal processing of information recorded on a magnetic tape are omitted.

FIG. 2 is a flowchart of the control section 2 showing abnormality detection processing of the magnetic head according to the present invention.

The control unit 2 detects the presence or absence of reproduction information from the magnetic tape T based on the output signal from the envelope detection circuit 3 (step S2), and if there is an envelope, starts a timer that counts down a predetermined time, for example, 5 seconds. are sequentially updated (step S3). In addition, if there is no envelope, that is, if it is determined NO in step S2, it is determined in step S4 whether the state has continued for 5 seconds or not based on the end of the timer, and if it has continued for 5 seconds, the unrecorded area is At the same time as setting the detection flag Fl, perform REV) drive control to rewind the magnetic tape T at the same speed as the fast forward (FF) running speed of the magnetic tape T at that time.Step 8
6 to 512), and starts a timer B that counts down for a time somewhat longer than the predetermined time (step 513).

Next, in step S1, it is determined that the unrecorded portion pressure detection flag Fl is 1, and in step S15, it is determined that the timer B has ended, and in step S16, the magnetic tape T is
The running direction of the magnetic tape is further reversed and the magnetic tape is driven at low speed in the same direction as the original FF reproduction, and a flag F2 is set to indicate that a magnetic head abnormality is being determined (step 5).
18).

After that, step S is passed through steps Sl and S14 again.
Moving on to step 18, it is determined whether the information was read by the magnetic head H or not, and it is determined whether the above-mentioned 5 seconds of no information was due to unrecorded information or whether the magnetic head H was able to read the information.
Step S19, 520 to detect whether this is due to an abnormality.
), the magnetic tape T is stopped (step S21). If it is determined that there is an unrecorded area, normal processing is continued, and if it is determined that the magnetic head H is abnormal, an alarm is issued to prompt processing such as cleaning the clogged magnetic head H.

Note that the control device that performs the abnormality detection process for the magnetic head and the control device that controls the traveling drive mechanism section l shown in FIG. 2 may be configured as separate devices. For example, the abnormality detection process for the magnetic head Control it with the main microcontroller shown in the figure,
The main microcomputer may send various commands to drive and control the travel drive mechanism section 1 to the deck microcomputer in order to detect an abnormality in the magnetic head.

Further, the magnetic head abnormality detection device of the present invention can be applied to devices other than magnetic tape devices used as external storage devices of computer systems, as shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, if information cannot be read during playback of a magnetic tape device, it can be quickly and accurately detected whether the cause is an unrecorded part of the information or an abnormality in the magnetic head. can.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a magnetic head abnormality detection device according to the present invention, FIG. 2 is a flowchart of the control unit 2 showing the magnetic head abnormality detection processing according to the present invention, and FIG. 3 is an external view of the computer system. FIG. 1 is a configuration diagram of a magnetic tape device used as a storage device. In the figure, l is a traveling drive mechanism section, 2 is a control section, and 3 is an envelope detection circuit. Applicant Fujitsu Ten Ltd.

Claims (1)

[Claims] 1. A magnetic tape running drive mechanism section, a control section that controls the running drive mechanism section, and means for detecting the presence or absence of reproduction information read by the magnetic head, and the control section is configured to When the information is not detected continuously for a predetermined period of time, the magnetic tape is rewound and reproduced to the position before the information was no longer detected, and the presence or absence of the reproduced information from the magnetic tape is detected. A magnetic head abnormality detection device characterized by detecting an abnormality in a magnetic head.