JPH04219607A - Method for detecting residual non-erased information on magnetic head - Google Patents

Abstract

PURPOSE:To improve the detecting accuracy of the residual non-erased information and the reliability of the recording information by setting a control standard value of the residual non-erased information in an erasing area as a low detecting standard value. CONSTITUTION:At a write-in command, a read-out detecting standard value to monitor the residual non-erased information in the erasing area is set at low. Also in the recording information area the read-out standard value to guarantee the reliability of the recording information is set at high. The switching of the read-out detecting standard value is based on the information appeared on the read-out head.

Description

【発明の詳細な説明】[Detailed description of the invention]

【０００１】0001

【産業上の利用分野】本発明は磁気テープの消去区域内
消し情報検出方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting erased information within an erased area of a magnetic tape.

【０００２】0002

【従来の技術】従来の磁気テープの消去区域内消し残し
情報検出方法は、図５に示すように、消去区域内の消し
残し情報を検出するために、書込み指令時と同期をとっ
て検出基準値を高い検出基準値にしている。なお、読み
取り指令時には低い検出基準値に変更する。2. Description of the Related Art In a conventional method for detecting unerased information in an erased area of a magnetic tape, as shown in FIG. The value is set to a high detection standard value. Note that when a reading command is issued, the detection reference value is changed to a lower one.

【０００３】0003

【発明が解決しようとする課題】上述した従来の磁気テ
ープの消去区域内消し残し情報検出方法では、図６に示
すように書込み時の消し残し情報監視が高い検出基準値
に設定されたままになっているため、検出基準値以下の
消し残し情報は検出されなかった。その結果、図７に示
すように、読み取り指令時に消去区域及び記録情報区域
の情報監視を低い検出基準値で行うので消し残し情報を
読み取り誤りとして検出するという問題点があった。[Problems to be Solved by the Invention] In the conventional method for detecting unerased information in an erased area of a magnetic tape as described above, as shown in FIG. Therefore, unerased information below the detection standard value was not detected. As a result, as shown in FIG. 7, since the information of the erased area and the recorded information area is monitored using a low detection standard value when a reading command is issued, there is a problem in that unerased information is detected as a reading error.

【０００４】0004

【課題を解決するための手段】本発明の消去区域内消し
残し方法の監視方法は、消去区域内の監視基準値として
低い検出基準値を採用し、記録情報区域内は高い検出基
準値で監視する方法をとっている。[Means for Solving the Problems] The monitoring method of the method for erasing unerased areas of the present invention adopts a low detection standard value as the monitoring standard value in the erased area, and monitors the recorded information area with a high detection standard value. I am taking a method to do so.

【０００５】[0005]

【実施例】次に本発明について図を参照して説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

【０００６】図３は、書込み時における磁気テープの走
行方向と磁気ヘッドの関係図である。FIG. 3 is a diagram showing the relationship between the running direction of the magnetic tape and the magnetic head during writing.

【０００７】図１は、本発明の動作原理を説明するもの
で、書込み指令時における磁気テープ媒体上の記録情報
と、書込みヘッドに表われる情報と読み取りヘッドに表
われる情報と、読み取り検出基準値を表わしている。FIG. 1 explains the operating principle of the present invention, and shows the information recorded on the magnetic tape medium at the time of a write command, the information appearing on the write head, the information appearing on the read head, and the read detection reference value. It represents.

【０００８】書込み指令時においては、消去区域内では
、消し残し情報を監視するため読み取り検出基準値は低
く設定される。また記録情報区域内においては、記録情
報の信頼性を保証するため読み取り検出基準値は高く設
定される。この読み取り検出基準値の切り換えは読み取
りヘッドに表われる情報に基ずく。[0008] At the time of a write command, the read detection reference value is set low in the erase area in order to monitor unerased information. Furthermore, within the recorded information area, the reading detection reference value is set high in order to guarantee the reliability of recorded information. This switching of the read detection reference value is based on information presented to the read head.

【０００９】図２は読み取り検出基準値の切り換え方法
の詳細図である。読み取り検出基準値を「低」から「高
」に切り換える条件は、読み取りヘッドに表われる読み
取り信号が１ビット以上検出されたときである。FIG. 2 is a detailed diagram of a method for switching the reading detection reference value. The condition for switching the read detection reference value from "low" to "high" is when one or more bits of the read signal appearing on the read head are detected.

【００１０】また、その逆に「高」から「低」に切り換
える条件は、読み取りヘッドに表われる信号が連続して
２ビット以上検出されないときである。On the other hand, the condition for switching from "high" to "low" is when two or more bits or more of the signal appearing on the reading head are not detected consecutively.

【００１１】図４は、消去区域内における消し残し検出
の応用図である。消去区域内においては、図２で説明し
たように読み取り検出基準値は低く設定されているので
、消し残し情報により読み取り信号が検出できる。読み
取られた信号が１ビット以上検出されると検出基準値を
「高く」して監視する。続く読み取り信号が連続して２
ビット検出されなかった場合再度検出基準値を「低く」
して消し残し情報の監視を継続する。FIG. 4 is an applied diagram of unerased area detection within an erased area. In the erasing area, the reading detection reference value is set low as explained in FIG. 2, so the reading signal can be detected based on the unerased information. When one or more bits of the read signal are detected, the detection reference value is set "high" and monitored. Two consecutive read signals
If the bit is not detected, set the detection standard value to "lower" again.
Continue to monitor unerased information.

【００１２】0012

【発明の効果】以上説明したように本発明は消去区域内
の消し残し情報の監視基準値を低い検出基準値としたの
で、消し残し情報の検出精度が上がり記録情報の信頼性
を向上させる効果を有する。As explained above, the present invention has the effect of increasing the accuracy of detecting unerased information and improving the reliability of recorded information since the monitoring reference value of unerased information in the erased area is set to a low detection standard value. has.

【図面の簡単な説明】[Brief explanation of the drawing]

【図１】図１は本発明の実施例のタイムチャート図、FIG. 1 is a time chart diagram of an embodiment of the present invention;

【
図２】図２は図１に市絵した読み取り情報検出基準値の
切り換え方法の詳細図、[
[Figure 2] Figure 2 is a detailed diagram of the method for switching the reading information detection reference value shown in Figure 1;

【図３】図３は書込み時における磁気テープの走行方向
と磁気ヘッドの関係図、[Fig. 3] Fig. 3 is a diagram showing the relationship between the running direction of the magnetic tape and the magnetic head during writing;

【図４】図４は消去区域内の消し残し情報の検出応用を
示す図、FIG. 4 is a diagram showing an application for detecting unerased information in an erased area;

【図５】図５は従来の消去区域内の消し残し情報監視方
法図、[Fig. 5] Fig. 5 is a diagram of a conventional method for monitoring unerased information in the erasing area;

【図６】図６は図５に示した方法による書込み指令時に
おける読み取り検出基準値の詳細図、[Fig. 6] Fig. 6 is a detailed diagram of the reading detection reference value at the time of a write command according to the method shown in Fig. 5;

【図７】図７は従来の読み取り指令時における読み取り
検出基準値の詳細図である。FIG. 7 is a detailed diagram of a reading detection reference value at the time of a conventional reading command.

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】　　消去区域内は低い読み取り検出基準値
、書込み情報区域内は高い読み取り検出基準値に設定し
、各区域内から読み取った情報を前記の対応する読み取
り検出基準値と比較する磁気テープの消し残し情報検出
方法。1. A magnetic tape in which a low read detection reference value is set within the erase area and a high read detection reference value is set within the write information area, and information read from within each area is compared with the corresponding read detection reference value. A method for detecting unerased information. 【請求項２】　　情報ビットが１個以上検出できた時点
から書込み情報であると見なし、監視基準値と高い検出
基準値に切り換え、また情報ビットが２個以上連続して
検出されなかった時点から書込み情報なしと判断して、
書込み情報監視基準値を低い検出基準値に切り換えるこ
とを特徴とする請求項１記載の磁気テープの消し残し情
報検出方法。[Claim 2] From the time when one or more information bits are detected, it is regarded as write information, and the monitoring standard value and the higher detection standard value are switched, and from the time when two or more information bits are not detected consecutively. It is determined that there is no written information,
2. The method for detecting unerased information on a magnetic tape according to claim 1, further comprising switching the written information monitoring reference value to a lower detection reference value.