JPH0115944B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a magnetic tape file for logging, particularly a magnetic tape file for logging that records logging data in real-time processing. The present invention relates to a magnetic tape file for logging configured such that marks are written and logging data is written over the tape marks during real-time processing.

Generally, in data processing systems, a method is used in which the operating status of the system is logged in a file in order to improve the reliability and maintainability of the system. FIG. 1 shows an example of the configuration of this type of system. In the figure, 1-0, 1-1, . . . , 1-n represent terminal devices, 2 a central processing unit, 3 a magnetic disk device, and 4 a magnetic tape file.

In Figure 1, when the system is performing normal real-time processing, each terminal device 1-0
The operating status of the system corresponds to 1 to 1-n, and the operating status of the system is 1 to 1-n.
will be recorded. When the central processing unit 2 or the magnetic disk device 3 fails, after removing the cause of the failure, the recorded contents of the magnetic tape file 4, that is, the logging data, are transferred to the magnetic disk device 3, and the original data can be restored in the event of a system failure. The state is restored and real-time processing continues.

2a, b, c, and d show an example of a recording method in which logging data is sequentially written to the magnetic tape file 4 in this type of system. In the figure, 5-0, 5-1, and 5-2 are data and
Blocks 5-3 and 6-0, 6-1, and 6-2 respectively represent incomplete data blocks when the write process is interrupted due to the occurrence of a failure as described above. As shown in Figure 2a,
When the constituent elements of the data block 5-0 are sequentially written onto the recording medium and the entire data block 5-0 has been written, then, for example, two tape marks 6-0 are written to the data block 5-0. Write adjacent to the zero end. And the next data block 5-
1, the data block 5-1 is overwritten on the tape mark 6-0, and the entire data block 5-1 is written. When the entire data block 5-1 is written, the tape mark 6-1 will be written to the data block 5-1 as in the case of writing data block 5-0 above.
Written adjacent to 1. Therefore, the recording state on the recording medium at the time when the tape mark 6-1 is written is as shown in FIG. 2b. Then, the next data block 5-2 and the tape mark 6 corresponding to the block 5-2
The writing process for tape mark 6-2 is carried out in the same way, and the recording state at the end of writing of tape mark 6-2 is as shown in FIG. 2c. Furthermore, while the write process for the next next data block (referring to the data block including the incomplete data block 5-3 shown in FIG. 2d) is being executed, if the above-described failure occurs. When this occurs and the write process stops, the recording state at that point is as shown in Figure 2d.
Block 5-0, data block 5-1, data block 5-2, and incomplete data block 5
-3.

After the failure occurs and the cause of the failure is removed, the process of transferring the recorded contents of the magnetic tape file 4 to the magnetic disk device 3 is performed as described above. That is, the recorded contents of the magnetic tape file 4 are read out and the read data is transferred to the magnetic disk device 3.
A process is performed to restore the system state to the state at the time the failure occurred. However, in the reading process of the magnetic tape file 4, if the recorded contents include an incomplete block 5-3 as described above in FIG. Occur.

The recorded contents at the time of failure are shown in Figure 2c.
As shown in the figure, if the tape mark 6-2 is written up to the point where the tape mark 6-2 was written, the end of the recorded content up to the time of the failure can be read by reading the tape mark 6-2 in the reading process. can be known.

The present invention aims to solve the above points,
It is an object of the present invention to provide a magnetic tape file for logging that can prevent the occurrence of tape runaway phenomenon. Therefore, in the logging magnetic tape file of the present invention, which records logging data in real-time processing, tape marks are written on all recording media by batch processing before the start of real-time processing, It is characterized in that it is configured such that logging data is written over the tape mark during real-time processing. The present invention will be explained below with reference to FIGS. 3a and 3b.

3a and 3b show an embodiment of the configuration of a magnetic tape file for logging according to the present invention, and FIG.
3 shows the recording state on the recording medium before starting real-time processing, and FIG. 3b shows the recording state on the recording medium at the time when a failure occurs during real-time processing. In the figure, 4,5-0,5-
1, 5-2, and 5-3 correspond to the same reference numerals in FIGS. 1 and 2, respectively, and 7 represents a tape mark in the present invention, respectively.

Before using magnetic tape file 4 as a logging file for real-time processing,
Figure 3a is applied to all areas on the recording medium by batch processing.
Write tape marks 7 as shown in the figure. Then, during real-time processing, logging data is overwritten on the tape mark 7 written as described above. Therefore, if a failure as described above occurs during real-time processing, the recording state on the recording medium will change to a tape mark after the end of the incomplete data block 5-3, as shown in FIG. 3b, for example. 7 is still recorded. Note that the data writing operation to the magnetic tape file 4 may be considered to be similar to the writing operation as described above in FIG.

In the read process of reading out the recorded contents of the magnetic tape file 4 after the cause of the failure has been removed, the data
Block 5-0, data block 5-1, and data block 5-2 are read out in sequence, and after incomplete data block 5-3 is read out, the subsequent tape mark 7 is read out. Become.
By reading this tape mark 7, for example,
The block length of the complete data block (illustrated data block 5-0, etc.) is compared with the block length of the incomplete data block 5-3,
Since there is a discrepancy, it can be determined that the incomplete data block 5-3 does not correspond to a complete data block, and the recorded contents up to data block 5-2 are considered valid and are stored in the magnetic disk device 3. will be forwarded to. As a result, the magnetic disk device 3
is set to approximately the same level as the storage state at the time of failure, allowing real-time processing to continue.

As described above, according to the present invention, since the storage state up to the time of failure can be accurately detected using tape marks, tape runaway phenomenon can be prevented.

[Brief explanation of drawings]

Figure 1 shows a logging magnetic tape according to the present invention.
A conceptual configuration example of a data processing system to which the file is applied; FIGS. 2a, b, c, and d are explanatory diagrams for explaining an example of a conventional magnetic tape file recording method; FIGS. 3a, b shows a diagram showing the main configuration in an embodiment of the present invention. In the figure, 4 is a magnetic tape file for logging,
5-0, 5-1, 5-2, 5-3 are data blocks that constitute logging data, and 7 is a tape block.
Each represents a mark.

Claims (1)

[Claims] 1 In the logging magnetic tape file that records logging data in real-time processing, tape marks are written on all recording media by batch processing before the start of real-time processing, and logging data is written to the above tape marks during real-time processing. A magnetic tape file for logging, characterized in that it is configured to be written on top of the file.