JPS623509B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a control method for a magnetic bubble storage device, and particularly to a control method when an error is found in read information.

Prior Art and Problems As shown in FIG. 1, a magnetic bubble memory device uses a bubble memory (consisting of a bubble chip, a drive coil, etc.) 20 in a host system (a central processing unit,
(CPU) 10 via a controller, and operates as an external storage device for the CPU 10.
The controller includes magnetic bubble information writing means 12,
It consists of a readout means 14, an error detection and correction means 16, and the like. Bubble memory 20 is generally a major
It is a minor loop type, and the number of minor loop bits (number of transfer patterns) and the number of minor loops determine the storage capacity. Writing is done on host system 1
Write data is sent in units of 8 bits or 16 bits starting from 0, and the writing means 12 receives this, converts the 8 bits or 16 bits parallel signal into a serial signal, and supplies this to the magnetic bubble generator of the bubble memory 20. The magnetic bubble generator generates bubbles in response to the serial signal, sequentially transfers them to the major loop, and when the number of bubbles generated equal to the number of minor loops (this is data for one page of memory) is transferred all at once to the minor loop. Writing into the bubble memory 20 is performed by repeating such operations.

Reading is still performed page by page. That is, when a desired (designated) page on the minor loop comes to the transfer gate to the major loop in bubble transfer, the gate is operated to transfer the bubbles of that page all at once to the major loop, and an electrical signal is sent through the bubble detector. , and amplify it with an amplifier to make it a TTL level signal. Since it is still a serial signal at this stage, this is an 8-bit or 16-bit signal.
It is converted into a bit parallel signal and transferred to the host system 10. The reading means 14 performs such amplification and serial/parallel conversion.

The data read from the bubble memory 20 is checked by the error detection and correction means 16, and if there is an error, if it can be corrected, it is corrected and sent to the host system 10, and also written into the bubble memory 20 for correction. Since an error check and correction code is added to the data written to the bubble memory, it is possible to correct small-bit errors determined by the code. If it is an uncorrectable multi-bit error, that fact is communicated to the host system, and reading is disabled.

However, such a memory system has the following problem. That is, the bubble is minute and the detector output is weak. This is amplified to the TTL level by a preamplifier, main amplifier, etc., and since it is an analog signal at the stage of detection, it is converted into a binary signal using a threshold value. At this time, the readout output may be erroneous even though the memory storage data is correct due to an error or noise contamination. This error detection and correction means 1
6, the correct data, in this case memory storage data, should be restored, but the error detection and correction means 16 does not always operate correctly and may end up correcting errors in the uncorrectable range. . In this case, the correction result is an error, and if this is written into the bubble memory and corrected, the correct stored data will be destroyed.

OBJECTS OF THE INVENTION The present invention aims to improve the above points and ensure the accuracy of memory storage data against errors occurring in the reading system.

Structure of the Invention The present invention provides a magnetic bubble memory comprising a bubble memory, a magnetic bubble information writing means, a magnetic bubble information reading means, and an error detection and correction means for detecting and correcting errors in information read from the bubble memory. In the control method of the apparatus, a readable/writable memory element for temporarily storing the read information, and a means for comparing the read information and the storage contents of the memory element are used to convert the read information from the bubble memory into the memory element. The data is stored in the memory element and checked by the error detection and correction means, and when an error is detected, the bubble memory is read out again and the read information is input to the comparison means and the error detection and correction means, and the memory element is reading and comparing the read information with the storage content of the storage element by the comparing means;
If they do not match, the correction result of the error detection and correction means is only sent to the host system, and if they match, the correction result of the error detection and correction means is sent to the host system and written to the bubble memory to correct the stored contents. Next, this will be explained in detail with reference to examples.

Embodiment of the Invention FIG. 2 shows an embodiment of the invention, in which the same parts as in FIG. 2 are given the same reference numerals. As is clear from a comparison with FIG.
A RAM (random access memory) 22 and read information comparison means 24 are provided. Figure 3 is the second
FIG. 3 is a circuit diagram illustrating the main part of the figure. Reference numeral 30 denotes a bubble memory controller, which includes the writing means 12 and reading means 14 shown in FIG. 2, and the like. 26 is an amplifier that amplifies the read information S1 of the bubble memory 20 to a TTL level signal, and its output S2 enters the controller 30 for transfer to the host system 10, and also enters the error detection and correction means 16 to detect errors. It is checked and entered into storage element 22 and stored there. Since reading is performed in page units, the capacity of the storage element 22 is, for example, 64 bytes for one page.

To explain the operation, the read information S2 is sent to the controller 30, error detection and correction means 16,
and enters the storage element 22 and the error detection and correction means 16
As long as no error is detected, the read information S2 is transferred to the host system in 8-bit or 16-bit units. When the error detection and correction means 16 detects an error, the controller 30 instructs rereading of the same page. This read information S2 is input to the comparator 24 and the error detection and correction means 16, and the error correction means 16 performs error correction. The controller 30 also instructs the reading of the storage element 22, and reads this read information S.
3 is also input to the comparator 24. The comparator 24 compares these pieces of information S2 and S3 bit by bit, and if they match,
Check for discrepancies. If the reading was performed correctly (according to the stored contents), the previous read information S3
should match the current read information S2,
If it is an error, the stored content itself is an error, so the controller 30 sends the correction result of the error detection and correction means 16 to the host system and writes it to the corresponding page of the bubble memory 20.

On the other hand, if there was an error in the previous read information S3 due to noise contamination, it is rare that the same error occurs in the current read information S2 (noise contamination is temporary), and S2≠S3. There is a high probability. In this case, the controller only sends the data corrected by the error detection and correction means 16 to the host system, but does not rewrite the data into the bubble memory or modify the memory contents. Whether or not the correction data sent to the host system is correct depends on whether the error detection and correction means operates normally.
This point (reliability) is similar to the conventional method, and the present invention has the advantage that correct memory storage data is not destroyed.

Effects of the Invention As explained above, according to the present invention, even if the stored data is correct, if the read output becomes an error due to noise contamination, the correct stored data will not be destroyed due to malfunction of the error detection and correction means. This greatly contributes to improving the reliability of magnetic bubble storage devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the structure of a magnetic bubble storage device, and FIGS. 2 and 3 are block diagrams showing embodiments of the present invention. In the drawing, 20 is a bubble memory, 12 is a writing means, 14 is a reading means, 16 is an error detection and correction means, 22 is a storage element, and 24 is a comparison means.

Claims (1)

[Scope of Claims] 1. A magnetic bubble comprising a bubble memory, magnetic bubble information writing means, magnetic bubble information reading means, and error detection and correction means for detecting and correcting errors in information read from the bubble memory. In a control method for a storage device, the reading information from the bubble memory is controlled by using a readable/writable storage element that temporarily stores the read information and a means for comparing the read information and the storage content of the storage element. The information is stored in the memory element and checked by the error detection and correction means, and when an error is detected, the bubble memory is read out again and the read information is input to the comparison means and the error detection and correction means. The comparison means compares the read information with the storage contents of the storage element, and if they do not match, the correction result of the error detection and correction means is only sent to the host system, and if they match, the error detection and correction means A control method for a magnetic bubble storage device characterized in that the correction result is sent to a host system and written into a bubble memory to correct the stored contents.