JPH05274845A - Controlling method for magnetic tape recording/ reproducing device - Google Patents

Abstract

PURPOSE:To greatly reduce a data reading time by directly retrieving a target 2 file without retrieving other files when the data of the target 2 file is read. CONSTITUTION:In a data backup system constituted of a DAT tape 1, the magnetic tape recording device 2 of a DAT system and a host computer 3, an information recording section 5 and a data recording section 6 are provided on the DAT tape 1 and at the time of data recording, information about its data is recorded in the information recording section 5. At the time of data reading, positional information is obtd. by referring to the data and the data is read our after a high speed searching is applied to its position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data backup system using a magnetic tape recording / reproducing apparatus, and more particularly to a method for controlling a magnetic tape recording / reproducing apparatus capable of searching a target position at high speed.

[0002]

2. Description of the Related Art A conventional technique is disclosed in JP-A-63-29353.
As described in No. 3, the absolute position information of the magnetic tape is recorded on the magnetic tape, and the tape position is searched based on that position information. The contents of the actually recorded data. Is not considered.

[0003]

The above-mentioned prior art considers the retrieval to the designated position, but does not consider where the target data is, and the target data is not considered. To find out
There is a problem in that it is necessary to read all the data written on the tape or a part of the beginning of the data for each data recording unit, and it takes a lot of time to reproduce the target data.

An object of the present invention is to provide a high-speed data backup system capable of searching a position and reproducing target data immediately when the target data is reproduced without reading the data written on the magnetic tape. To provide.

[0005]

In order to achieve the above object, in the present invention, a direct accessible area is created at the head of the magnetic tape, and an area for sequentially recording data is provided at the back of the area. ..

Information such as a file name, a head position, and a capacity is stored in the directly accessible area for each file to be recorded. When a file is added, the data is additionally recorded at the rear end of the data recording section and the above information is added. When reading a file, the above information is searched for from the file name, the file position is acquired, and a high speed search is performed up to that position. Then, the data is read from that position.

[0007]

The area for recording the file information at the head of the magnetic tape is secured and initialized in a predetermined area. Since this area is directly accessed, partial rewriting is possible. Therefore, in this area where file information is stored, information can be added even when files are added.

Since all the information of the recorded file is stored in the above area, if only this area is read, the position information of all the formats recorded on the tape is maintained, so that useless data is stored. Without reading
You can search the location of the desired file immediately.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a block diagram of a data backup system which is an embodiment of the present invention.

As a data backup system of the present invention, a case where a DAT type magnetic tape recording device 2 for recording data on a DAT (digital audio tape recorder) tape 1 is used will be described. Other components of the system are the host computer 3 and the internal storage device 4 of the host computer 3. Also, DAT tape 1
Is divided into an information recording section 5 and a data recording section 6.

FIG. 2 shows the tape structure of the DAT tape 1. The DAT tape 1 has an information recording section 5,
It is divided into a data recording section 6 and a non-recording section 7, and only the information recording section 5 exists when no data is recorded. On the other hand, the information recording unit 5 is created by an instruction from the host computer 3. When writing a file, the data of the file is written into the data recording unit 6 following the rear end of the information recording unit 5. Therefore, the data recording unit 6 becomes larger each time a file is added.

In the information recording section 5, file information 8 consisting of information such as file name, file position information, file capacity, etc. is recorded for each file written in the data recording section 6, and referred to at the time of data retrieval. It

FIG. 3 shows a processing procedure when the host computer 3 records data.

First, prior to data recording, the DAT tape 1
The contents of the information recording unit 5 are read into the internal storage device 4 of the host computer 3. (Step 31) Next, the position of the rear end of the data recording section 6 is calculated from the information, and a high speed search is performed up to that position. (Step 32) Next, data is additionally recorded from that position. (Step 33) After the data recording is completed, the file information of the added data is added to the file information stored in the internal storage device 4. (Step 34) Finally, the file information stored in the internal storage device 4 is written in the information recording unit 5. (Step 35) FIG. 4 shows a processing procedure when the host computer 3 reproduces data.

First, the contents of the information recording section 5 of the DAT tape 1 are read into the internal storage device 4 of the host computer 3. (Step 41) Next, the information of the target file is searched from the information to obtain the position information of the target file. (Step 42) A high speed search is performed to the target position based on the position information, and (Step 43) data is read from the position (Step 44).

[0017]

Conventionally, in order to read the target file, the files are searched in order from the file at the beginning of the tape, and the beginning of the file is read to identify whether it is the target file. Since the above operation is repeated until the target file is found, the more data there is at the back of the tape, the longer it took to read. On the other hand, according to the present embodiment, it is possible to know the information such as the file name, recording position, and capacity of the file recorded on the tape.
You can search and read the target file. Therefore, the reading time can be greatly shortened as compared with the conventional method. For example, when there are 100 files and the 90th file is read, according to the conventional method, the file at the beginning of the tape, that is, the 1st file is searched, and the 2nd file and the 3rd file are sequentially searched. The file, the 4th file ... And the 90th target file are searched and the data is read. On the other hand, according to the method of the present invention, when the 90th file is read, the 90th file can be directly searched and the data can be read, so that the file can be read as compared with the conventional method. The search time can be reduced to about 1/90.

[Brief description of drawings]

FIG. 1 is a block diagram of a data backup system that is an embodiment of the present invention.

FIG. 2 is a tape configuration diagram of a DAT tape.

FIG. 3 is a flowchart of a data recording process.

FIG. 4 is a flowchart of a data reading process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... DAT tape, 2 ... DAT type magnetic tape recording device, 3 ... Host computer, 4 ... Internal storage device of host computer, 5 ... Information recording part of DAT tape, 6 ... Data recording part of DAT tape,

Claims (1)

[Claims] 1. A data backup system comprising a magnetic tape, a magnetic tape recording / reproducing device for recording / reproducing data on / from the magnetic tape, and a host computer for controlling the magnetic tape recording / reproducing device. An area is provided, a data recording area is provided by a sequential access method after the area, and position information of data to be recorded by the sequential access method is recorded in the rewritable area of the magnetic tape. Device control method.