JPH06259930A - High-speed program searching system for magnetic tape film - Google Patents

Abstract

PURPOSE:To shorten the time for retrieving files and to improve operability by making the starting and finishing positions of each file on a magnetic tape corresponsive to the rotative number of a reel shaft and recording them on a volume management area as file management information. CONSTITUTION:The volume management area is provided on the head of the magnetic tape, the starting and finishing positions of each file on the magnetic tape are made corresponsive to the rotative number of the reel shaft and recorded as the file management information. When the magnetic tape is loaded on a magnetic tape device, the file management information is loaded to a memory on the magnetic tape device and the files are retrieved. For example, in the case of a file name C, that its starting position is the 124th of the rotation is discriminated, the tape is fast-forwarded at a normal rewinding speed for retrieving the file and positioned on the head of the file name C. Thus, the time for retrieving the files is shortened and the operability of the magnetic tape is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed cueing system for magnetic tape files, and more particularly to a magnetic tape file of a multi-file format and a multi-volume file format in which necessary files can be searched at high speed and randomly. Of high-speed cueing method.

[0002]

2. Description of the Related Art Conventionally, a file recorded on a magnetic tape of a multi-file or multi-volume file format is searched for by sequentially reading a file header label recorded at the head of each file from the head of a magnetic tape volume. It went and skipped until the corresponding file header label was found.

Further, when returning from a file having a large file sequence number to a file having a small file sequence number in the same volume, a method of rewinding to the head of the magnetic tape and then searching again from the head has been adopted.

[0004]

According to the conventional magnetic tape file retrieval method described above, the contents of the file header label are read from the beginning of the magnetic tape volume at a speed at which the contents can be read, and the file header label having the corresponding file name is read. Since the method skips until the file is found, if the file is located behind the magnetic tape, it takes a very long time to reach the position of the file.

Further, when returning from a file having a large file sequential number to a file having a small file number in the same volume, the method of rewinding to the beginning of the magnetic tape and then searching again from the beginning is adopted. It was necessary to operate in consideration of the storage order.

An object of the present invention is to provide a high-speed cueing method for magnetic tape files, which can search required files at high speed and randomly.

[0007]

A high-speed cueing method for a magnetic tape file according to the present invention is such that the start and end positions of a file recorded on the magnetic tape at the head of the magnetic tape are rotated from the head of the magnetic tape by a reel shaft. A counter for counting the number of rotations of the reel axis from the beginning of the magnetic tape in the magnetic tape device, and a file in the volume management area when the magnetic tape is mounted, by creating a volume management area in which file information including position information displayed in number is recorded. Management means for loading information into the memory and updating the file information in the volume management area of the magnetic tape with the file information on the memory at the end of rewinding, and a reel corresponding to the start and end positions of each file on the magnetic tape File head that acquires the axis rotation speed and rotates at high speed immediately before that to find the corresponding file It is configured to include a means to.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is an explanatory view of a label format in one embodiment of the present invention. FIG. 1A shows the label format of this embodiment.
FIG. 1B shows a label format of a conventional magnetic tape. The difference between the conventional label format and the label format of this embodiment is that, in the case of the label format of this embodiment, there is a volume management area immediately after the head volume heading label (VOL).

FIG. 2 shows an example of the contents of one file of the file information in the volume management area. The number of revolutions of the reel shaft from the beginning of the magnetic tape corresponding to the start and end positions of the file is recorded as the start position revolution number and the end position revolution number, respectively, together with various information regarding the file name. An area that can store such file information for 1000 files is secured at the time of initialization of the magnetic tape volume as a volume management area.

Next, the operation of the high-speed cueing method for the magnetic tape file of this embodiment will be described with reference to FIG.

FIG. 3A shows the operation when the magnetic tape volume is mounted on the magnetic tape device. At the same time when the VOL is detected, the file information in the volume management area is read and loaded into the volume management area area 3 on the memory 2 of the magnetic tape device controller 1. At this time, a tape rotation counter area 4 for recording the count number of a tape rotation counter for counting the rotation number of the reel axis of the magnetic tape is secured in the memory 2 of the magnetic tape device control unit 1, and its value is set to an initial value " Set to 0 ". This tape rotation counter indicates the number of rotations from the beginning of the data recording area of the magnetic tape to the current position, and is counted up each time the magnetic tape rotates in the normal rotation direction (rotation direction during reading), When rotating in the opposite direction (rotating direction during rewinding), the countdown is performed.

FIG. 3B shows a file writing operation on the magnetic tape. When writing the file with the file name A in the state of FIG. 3A, first, the current position (rotation speed =
0) is obtained from the tape rotation counter area 4 on the memory 2, and “A” is added to the file name section of the file information (only the items necessary for explanation are shown in FIG. 3) in the volume management area area 3. "0" is stored in the item of the start position (field of the start position rotation number in FIG. 2). After that, the data of the file name A is written on the magnetic tape, and when the writing is completed, the end position (rotation speed = 100) is acquired from the tape rotation counter area 4 and the end position of the file information in the volume management area area 3 ( It is stored in the item of “start position rotation speed field” in FIG. The information in the volume management area area 3 on the memory is written to the volume management area on the magnetic tape at the end of rewinding the magnetic tape.

FIG. 3C shows the positioning operation of the magnetic tape file. When the already written magnetic tape is mounted on the magnetic tape device, the file information of the file names A to F shown in FIG. 3C is read from the volume management area of the magnetic tape to the volume management area area 3 on the memory 2. Be done. Here, when positioning to the file of the file name C, first, the start position of the file name C is acquired from the file information of the volume management area area 3. If the start position of the file name C is the 124th rotation, the reel shaft is rotated in the forward direction at a speed equivalent to the conventional rewind speed for 121 rotations of a value obtained by subtracting a fixed number (for example, 3) from the value. Fast forward the tape. After 121 rotations, the HDR (file header label) of the file name C is searched from that position at a readable speed, and the file with the file name C is positioned at the beginning.

[0015]

As described above, according to the high-speed cueing method for magnetic tape files of the present invention, the start and end positions of each file on the magnetic tape are associated with the number of rotations of the reel shaft, and By recording the file management information in the volume management area, the file search process can be performed at the conventional rewind speed, and the corresponding file can be searched for in a short time. Also, even when returning to the reverse direction and searching for a file, it is not necessary to go back to the beginning and search from the beginning again, and the time required for the file search is greatly shortened compared to the conventional method. Has the effect of improving.

[Brief description of drawings]

FIG. 1 is a comparative explanatory diagram of a label format according to an embodiment of the present invention and a conventional label format.

FIG. 2 is an explanatory diagram of recorded information in a volume management area according to this embodiment.

FIG. 3 is an explanatory diagram of file writing and positioning operation in the present embodiment.

[Explanation of symbols]

 1 magnetic tape device control unit 2 memory 3 volume management area area 4 tape rotation counter area

Claims (1)

[Claims] 1. A volume management area in which the file information including the position information in which the start and end positions of the file recorded on the magnetic tape are displayed by the number of rotations of the reel axis from the beginning of the magnetic tape is recorded at the beginning of the magnetic tape. A counter that creates and counts the number of reel shaft rotations from the beginning of the magnetic tape in the magnetic tape device, and loads the file information in the volume management area into the memory when the magnetic tape is loaded and uses the file information in the memory at the end of rewinding. The management means for updating the file information in the volume management area of the magnetic tape and the reel axis rotation speed corresponding to the start and end positions of each file on the magnetic tape are obtained, and the reels are rotated at a high speed until immediately before that. High-speed cueing of a magnetic tape file, characterized by having a file cueing means for cueing Method.