JPH02254677A - Magnetic tape controller - Google Patents

Abstract

PURPOSE:To speed up an information processing by providing a mode storage part to store a mode to indicate the beacon of the processing as to an error related to a block number detected with a data format. CONSTITUTION:A data format control circuit 14 arranges the format of write data by adding the block number designated with a microprocessor 15 and, simultaneously, adding an error correcting code, a period signal, etc., at the time of transferring the write data from a data buffer 13 to a magnetic tape device 3, further, detects the error of the block number and corrects it. Namely, a mode storage part 17 stores the mode to indicate whether to execute an abnormality report to a high order device in suspending the processing or to continue the processing in ignoring the error when the microprocessor 15 receives the error related to the block number detected by the data format control circuit 14. By consciously ignoring the error of the block number, the effective utilization of the other data and the speed-up of the information processing can be executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic tape control device used as an auxiliary storage device of a computer, etc., and in particular, the present invention relates to a control device for a magnetic tape used as an auxiliary storage device of a computer, etc. The present invention relates to a magnetic tape control device that can effectively utilize other data by ignoring other data.

[Prior Art] Conventionally, when data blocks stored on a magnetic tape are successively read, there have been accidents in which data blocks that should exist are not detected and are dropped. To prevent this, the software adds a serial number to each block and checks that the numbers are consecutive when reading data blocks.

In recent years, block numbers have been added to all data blocks, and mainly magnetic tape subsystems have automatically added numbers to written data. When reading data, this magnetic tape subsystem checks the data block number, and if it detects a 2 error, it reports it to the host system as an abnormal state.

[Problems to be solved] Multiple data files are stored on the magnetic tape roll mentioned above, and even if discontinuity in block numbers is detected in some areas, it is difficult to use the data in other normal blocks as is. There were strong demands.

However, according to the above-mentioned method of automatically adding block numbers using the conventional magnetic tape subsystem, if discontinuity of block numbers is detected in the subsystem during information processing, the upper A report was sent to the system that the process had ended due to an abnormal condition, the magnetic tape device stopped working, and the process was interrupted. For this reason, the software must reposition the magnetic tape by adding the correct block number, and then perform further data reading processing, which may impede urgent processing operations.

The present invention has been made in view of the above-mentioned problems.
An object of the present invention is to provide a magnetic tape control device that can make effective use of other data and speed up information processing by intentionally ignoring detection of errors in block numbers.

[Means for Solving the Problems] In order to achieve the above object, the magnetic tape control device of the present invention includes a channel connection section for connection to a channel, a magnetic tape connection section for connection to a magnetic tape device, and a data buffer. A data format control circuit that adds a buffer number when transferring data to a magnetic tape device, detects and corrects errors, and a microprocessor that processes the lock number detected by the data format control circuit. The present invention has a block number storage unit that stores block numbers, and a mode storage unit that stores a mode that indicates processing guidelines for errors related to block numbers detected by the data format.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a magnetic tape control device according to an embodiment of the present invention, and FIG. 2 is a flowchart showing an example of the operation of the magnetic tape control device according to this embodiment.

In the drawings, reference numeral 1 denotes a magnetic tape control device (hereinafter referred to as the control device), which is interposed between the channel 2 and the magnetic tape control device 3 and connects the two.

Inside the control device 1, a channel connection section 11 for connection to the channel 2 and a magnetic tape connection section 12 for connection to the magnetic tape device 3 are provided.

A data buffer 13 temporarily stores data transferred between the channel 2 and the magnetic tape device 3.

14 is a data format control circuit which, when transferring write data from the data buffer 13 to the magnetic tape device 3, adds a block number specified by a microprocessor 15, which will be described later, as well as an error correction code, a periodic signal, etc. By doing this, the format of the written data is adjusted, and errors in block numbers are detected and corrected. Also, when reading data from the 1m tape stirrup 3, block numbers etc. added to the data are removed by the method described above. Then, only the data necessary for the host device is transferred to the data buffer 13.

The microprocessor 15 receives the block number detected by the data format control circuit 14 at the time of transfer of write data, the result of the corrected data number, and further receives the number removed at the time of data read, thereby storing the block number storage section described later. 16 and mode storage section 1
The block number is processed under the supervision of step 7.

The block number storage unit 16 stores the block number that the microprocessor 15 is processing or the block number that should be processed next. Furthermore, when the microprocessor 15 receives an error related to a block number detected by the data format control circuit 14 (hereinafter referred to as a block sequence error), the mode storage unit 17 interrupts the processing and reports an abnormality to the host device. Stores a mode indicating whether to do so or ignore the error and continue processing.

Next, an example of the operation of this embodiment will be described.

First, the software adds a block number to the data during writing, and when attempting to read this from the magnetic tape device 3 with the first read command, it sets the block sequence non-check mode via channel 2 by a mode set command in advance. and instructs the control device 1.

On the other hand, in the control device 1, the microprocessor 15 sets the bit corresponding to the corresponding magnetic tape device 3 in the mode storage section 17 to "1".

Here, when multiple read commands are sent to the magnetic tape device 3 following a rewind command, the microprocessor 1
5 first sets "0000" in the area of the block number storage section 16 corresponding to the magnetic tape device at the time when the starting end of the tape is detected. When the first block is read by the next read command, the data format control circuit 14 adds a block number and checks whether there is a data error. If a data error is detected here (Figure 2: 101), the data error is reported to the host device or a retry process is performed (Figure 2:
102).

If no data error is detected, the added block number is separated and sent to the microprocessor 15.

The microprocessor 15 compares the sent number with the data in the block number storage section 16 (Fig. 2: 103).
), if the comparison results match, the contents of the block number storage unit 16 are incremented by 1 (Fig. 2: 104). After that, each block is incremented by 1, and this and each block are incremented by 1. The block number is compared with the block number (FIG. 2: 105).

Here, if the comparison result is a mismatch, for example, if the content of the block number storage section 16 is "n".

If the block number separated by the data format control circuit 14 is "n+1", the number of tries will be exceeded. In this state, the microprocessor 15 detects a comparison error and instructs the magnetic tape device 3 via the magnetic tape controller 12 to reverse space operations for several blocks. Then, data is read in the forward direction, and when the data format control circuit 14 detects the block with block number "n-1", the data is read out in the forward direction.
When block number -1' is detected (Figure 2: 106)
, reread block number “n” (Figure 2: 106)
L/, if detected, executes the next instruction. At this time, if the block number "n" cannot be detected even after performing the above-mentioned backward space and rereading several times, check the bit corresponding to the magnetic tape device 3 in the mode storage section 17. (Figure 2: 108), if the checked bit is "O", the magnetic tape controller 2 reports an abnormality of "block sequence error" to the host device and ends the process (+109 in Figure 2).

On the other hand, if the checked bit is "1", the microprocessor 15 transfers the data of block "n+1" to channel 2 following block "n", and stores the block number "" in the corresponding area of the block number storage section 16. After setting "n+2", the primary processing is continued. After that, the software rearranges the sent data block by block or leaves block "n" blank.
By invalidating this part, other data can be used effectively without interrupting processing.

Furthermore, in this embodiment, reading of a tape with block numbers added to the data blocks has been explained, but when reading a tape without block numbers added to the data blocks, a block sequence check mode is sent in advance by a mode set command, and the mode By setting this bit in the storage unit 17 to 0'', it is possible to prevent processing interruption due to an error in the data order.

Although this embodiment shows an example of reading the magnetic tape in the forward direction, reading in the reverse direction can also be performed by the same means.

[Effects of the Invention] As explained above, the present invention has the effect that by consciously ignoring errors in block numbers, it is possible to effectively utilize other data and speed up information processing. be.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a magnetic tape control device according to an embodiment of the present invention, and FIG. 2 is a flowchart showing an example of the operation of the magnetic tape control device according to this embodiment. 1: Magnetic tape control device 2: Channel 3: Magnetic tape device ll: Channel connection section 12: Magnetic tape device connection section 13: Data buffer 14: Data format control circuit 15: Microprocessor 16: Block number storage section 17: Mode storage Department Agent Patent Attorney Kihei Watanabe

Claims (1)

[Claims] A channel connection section that connects to a channel, a magnetic tape connection section that connects a magnetic tape device, and a data format that adds a buffer number when transferring data from the data buffer to the magnetic tape device and detects and corrects errors. A control circuit, a microprocessor that processes the baroque number detected by the data format control circuit, a block number storage unit that stores the block number being processed by the microprocessor, and a block number storage unit that processes an error related to the block number detected by the data format. 1. A magnetic tape control device comprising: a mode storage unit storing a mode indicating a guideline for the magnetic tape control device.