Computer system having facility for detection of data abnormalities

• US 6,023,774 A
• Filed: 08/02/1996
• Issued: 02/08/2000
• Est. Priority Date: 10/12/1993
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Minagawa, Akitaka
• Primary Examiner(s): LE, DIEU MINH T
• Application Number:
  US08/691,443
• Time in Patent Office: 1,285 Days
• Field of Search: 395/183.19, 395/183.2, 371/20.5, 371/67.1, 371/68.1, 371/68.2, 371/71, 371/20.1, 370/249, 370/242, 714/43, 714/44, 714/716, 714/717, 714/819, 714/820, 714/821
• US Class Current: 714/43
• CPC Class Codes: G06F 11/1443 Transmit or communication errors

Abstract

A computer system which includes data transmission line and a plurality of data transmissions apparatuses connected in parallel to the data transmission line. Each data transmission apparatus generates transmission data and provides the generated transmission data to the data transmission line. In each data transmission apparatus, the generated transmission data provided to the data transmission line is wrapped around back to the respective data transmission apparatus without passing through any other data transmission apparatus. Each data transmission apparatus includes a data abnormality monitoring unit which determines whether the generated transmission data correlates with the transmission data which was wrapped around. It is determined that an abnormality occurred when the data abnormality monitoring unit determines that the generated transmission data does not correlate with the transmission data which was wrapped around.

Claims

1. A computer system having a facility for detection of data abnormalities, provided with a data transmission line and a plurality of data transmission apparatuses connected in common to the data transmission line, wherein:

each data transmission apparatus generates transmission data to be output therefrom to the data transmission line, and is provided with a data abnormality monitoring means for detecting an abnormality in the data output to the transmission line,

transmission data generated in each data transmission apparatus to be output therefrom to the data transmission line is wrapped around inside the respective data transmission apparatus to produce wrapped data, and

the wrapped data inside each data transmission apparatus is input to the data abnormality monitoring means of the respective data transmission apparatus, the correlation of the wrapped data with the transmission data is monitored by the data abnormality monitoring means, and, when there is no correlation, it is determined that an abnormality has occurred in the transmission of data, so that each data transmission apparatus determines that an abnormality has occurred within the respective data transmission apparatus without relying on data from another data transmission apparatus.

2. A computer system having a facility for detection of data abnormalities as set forth in claim 1, wherein when data is transmitted under a frame synchronization system, a first bit pattern is assigned to the beginning of each said transmission data as a start flag and a second bit pattern is assigned to the end of each said transmission data as a stop flag, the first bit pattern and the second bit pattern being selected from an arbitrary arrangement of "1" and "0" bit series excluding an all "1" bit series and an all "0" bit series.

3. A computer system having a facility for detection of data abnormalities as set forth in claim 1, wherein said data abnormality monitoring means detects points of change of the input wrapped data and when the number of points of change detected is less than a predetermined reference value, it determines that there is no correlation and an abnormality has occurred in the transmission of data.

4. A computer system having a facility for detection of data abnormalities as set forth in claim 3, wherein said reference value is one value selected from among a plurality of predetermined reference values.

5. A computer system having a facility for detection of data abnormalities as set forth in claim 1, wherein said data abnormality monitoring means compares the transmission data output from the data transmission apparatus to the data transmission line and the wrapped data produced by wrapping in the data transmission apparatus and, when the two do not coincide, determines that there is no correlation and an abnormality has occurred in the transmission of data.

6. A computer system having a facility for detection of data abnormalities as set forth in claim 5, wherein the transmission data and the wrapped data are synchronized and the two are sequentially compared bit by bit.

7. A computer system having a facility for detection of data abnormalities as set forth in claim 1, wherein a switch means is provided in each data transmission apparatus at the connecting portion with the data transmission line, the switch means being opened to disconnect the data transmission apparatus and the data transmission line when the data abnormality monitoring means determines that there is no correlation.

8. A computer system having a facility for detection of data abnormalities as set forth in claim 7, wherein a wrap test of the transmission data is executed in the data transmission apparatus in the state with the switch means opened and the switch means being once again closed to connect with the data transmission line when no abnormality is detected in the data transmission as a result of the wrap test.

9. A computer system having a facility for detection of data abnormalities, provided with a data transmission line and a plurality of data transmission apparatuses connected in common to the data transmission line, wherein each data transmission apparatus is provided with:

a central processing unit for transmission and reception of data with the data transmission line,

a transmission/reception control unit connected with the central processing unit and controlling transmission and reception of the transmission data and received data,

a driver for outputting the transmission data to the data transmission line,

a receiver for receiving as input the data received from the data transmission line, and

a data abnormality monitoring means for receiving as input the data received from the receiver, monitoring the correlation with the transmission data, and, when there is no correlation, determining that an abnormality has occurred in the transmission of the data, so that the data transmission apparatus determines that an abnormality has occurred without relying on data from another data transmission apparatus connected to the data transmission line.

10. A computer system having a facility for detection of data abnormalities as set forth in claim 9, wherein the data abnormality monitoring means is comprised of a changing point detecting unit which detects the points of change of the input received data, which means determines that an abnormality has occurred in the transmission of data when the number of points of change is less than a predetermined reference value.

11. A computer system having a facility for detection of data abnormalities as set forth in claim 10, wherein the data transmission apparatus comprises:

a changing point frequency selector for detecting that the number of points of change is less than a predetermined reference value, and

a changing point frequency latch for holding the results of detection by the change point frequency selector and for interrupting the central processing unit.

12. A computer system having a facility for detection of data abnormalities as set forth in claim 9, wherein the data abnormality monitoring means is comprised of a comparator which compares the input received data and the transmission data at the input side of the driver and determines that an abnormality has occurred in the transmission of data when the result of the comparison is that there is no coincidence.

13. A computer system having a facility for detection of data abnormalities as set forth in claim 12, wherein the transmission data and the received data are synchronized and a transmission data latch and received data latch are provided for temporarily holding the two at the input side of the comparator.

14. A computer system having a facility for detection of data abnormalities as set forth in claim 9, wherein the data transmission apparatus is further provided with a switch means inserted between the commonly connected driver output side and receiver input side and the data transmission line and a line disconnection control means for controlling the opening and closing the switch means, the switch means being opened through the line disconnection control means when it is determined by the data abnormality monitoring means that an abnormality has occurred in the transmission of data.

15. A computer system having a facility for detection of data abnormalities as set forth in claim 14, wherein a wrap test is executed in the data transmission apparatus by the central processing unit in the state with the switch means opened.

16. A computer system comprising:

a data transmission line; and

a plurality of data transmissions apparatuses connected in parallel to the data transmission line, each data transmission apparatus generating transmission data and providing the generated transmission data to the data transmission line, the generated transmission data provided to the data transmission line being wrapped around back to the respective data transmission apparatus without passing through any other data transmission apparatus, the wrapped generated transmission data being defined as wrapped data, each data transmission apparatus comprising;

a data abnormality monitoring unit which receives the generated transmission data and the wrapped data, and determines whether the generated transmission data correlates with the wrapped data, wherein it is determined that an abnormality occurred when the generated transmission data does not correlate with the wrapped data, so that the data transmission apparatus determines that an abnormality has occurred without relying on data from another data transmission apparatus.

17. A computer system as set forth in claim 16, wherein data is transmitted under a frame synchronization system and, for each data transmission apparatus of the plurality of data transmission apparatuses, a first bit pattern is assigned to the beginning of the generated transmission data as a start flag and a second bit pattern is assigned to the end of the generated transmission data as a stop flag, the first bit pattern and the second bit pattern being selected from an arbitrary arrangement of "1" and "0" bit series excluding an all "1" bit series and an all "0" bit series.

18. A computer system as forth in claim 16, wherein the data abnormality monitoring unit of each data transmission apparatus comprises:

means for detecting points of change of the wrapped data, and

means for comparing the detected points of change with a reference value, the data abnormality monitoring unit determining that the generated transmission data does not correlate with the wrapped data when the number of detected points is less than the reference value.

19. A computer system as set forth in claim 18, wherein the reference value is one value selected from among a plurality of reference values.

20. A computer system as set forth in claim 16, wherein, when the data abnormality monitoring unit of a respective data transmission apparatus determines that the generated transmission data does not correlate with the wrapped data, the data abnormality monitoring unit determines that an error occurred in the providing of the generated transmission data from the respective data transmission apparatus to the data transmission line.

21. A computer system as set forth in claim 20, wherein the transmission data and the wrapped data of each data transmission apparatus are synchronized and sequentially compared bit by bit by the data abnormality monitoring unit of the respective data transmission apparatus.

22. A computer system as set forth in claim 16, wherein each data transmission apparatus further comprises:

a switch having a closed position to connect the data transmission apparatus to the data transmission line, and an open position to disconnect the data transmission apparatus from the data transmission line, and

a means for opening the switch to disconnect the data transmission apparatus from the data transmission line when it is determined that an abnormality occurred.

23. A computer system as set forth in claim 22, wherein, in each data transmission apparatus, the data abnormality monitoring unit determines whether the generated transmission data correlates with the wrapped data with the switch of the respective data transmission apparatus being open and, when the generated transmission data correlates with the wrapped data, the switch is closed to connect the data transmission apparatus to the data transmission line, thereby preventing the generated transmission data from being provided to the data transmission line when an abnormality occurred.

24. A computer system as set forth in claim 16, wherein each data transmission apparatus further comprises:

a receiver for receiving data from the data transmission line, the wrapped data being received by the receiver from the data transmission line, and the data abnormality monitoring unit receiving the wrapped data from the receiver.

25. A computer system as set forth in claim 24, wherein the data abnormality monitoring unit of each data transmission apparatus further comprises:

a change point detecting unit for detecting points of change of the wrapped data, and for comparing the detected points of change with a reference value, the data abnormality monitoring unit determining that the generated transmission data does not correlate with the wrapped data when the number of detected points is less than the reference value.

26. A computer system as set forth in claim 25, wherein each data transmission apparatus includes a central processing unit for controlling the data transmission apparatus, and the data abnormality monitoring unit of each data transmission apparatus comprises:

a changing point frequency selector for detecting that the number of points of change is less than a predetermined reference value, and

a changing point frequency latch for holding the result of detection by the change point frequency selector and for interrupting the central processing unit when the result of detection indicates that an abnormality occurred.

27. A computer system as set forth in claim 24, wherein the data abnormality monitoring unit of each data transmission apparatus further comprises:

a comparator which receives the generated transmission data and the wrapped data and compares the received generated transmission data and the received wrapped data.

28. A computer system as set forth in claim 27, wherein the generated transmission data and the wrapped data are synchronized, and each data transmission apparatus further comprises:

a transmission data latch for temporarily holding the generated transmission data before the generated transmission data is received by the comparator; and

a received data latch for temporarily holding the wrapped data before the wrapped data is received by the comparator.

29. A computer system as set forth in claim 24, wherein each data transmission apparatus further comprises:

a switch having a closed position to connect the data transmission apparatus to the data transmission line, and an open position to disconnect the data transmission apparatus from the data transmission line, and

a means for opening the switch to disconnect the data transmission apparatus from the data transmission line when it is determined that an abnormality occurred.

30. A computer system as set forth in claim 29, wherein, in each data transmission apparatus, the data abnormality monitoring unit determines whether the generated transmission data correlates with the wrapped data with the switch of the respective data transmission apparatus being open, thereby preventing the generated transmission data from being provided to the data transmission line until it is determined whether an abnormality occurred.

31. A computer system comprising:

a data transmission line; and

a plurality of data transmission apparatuses connected to the data transmission line, each data transmission apparatus generating transmission data and providing the generated transmission data to the data transmission line, the generated transmission data provided to the data transmission line being wrapped around back to the respective data transmission apparatus without passing through any other data transmission apparatus, the wrapped generated transmission data being defined as wrapped data, each data transmission apparatus comprising;

a data abnormality monitoring unit which receives the generated transmission data and the wrapped data, and determines whether the generated transmission data correlates with the wrapped data, wherein it is determined that an abnormality occurred when the generated transmission data does not correlate with the wrapped data, so that the data transmission apparatus determines that an abnormality has occurred without relying on data from another data transmission apparatus.

32. A data transmission apparatus connected to a data transmission line, the data transmission apparatus comprising:

a data generating device which generates data and provides the generated data to the data transmission line, the generated data provided to the data transmission line being wrapped around back to the data transmission apparatus without passing through any other data transmission apparatuses connected to the data transmission line; and

a data abnormality monitoring unit which receives the generated data and the wrapped generated data, determines whether the generated data correlates with the wrapped generated data, and determines that an abnormality has occurred in the data transmission apparatus when the generated data does not correlate with the wrapped generated data, so that the data transmission apparatus determines that an abnormality has occurred without relying on data from another data transmission apparatus connected to the data transmission line.

33. A communication system comprising:

a transmission line;

first and second processing devices connect to each other through the transmission line, wherein the first processing device includes;

a data generating device which generates data for transmission to the second processing device and provides the generated data to the transmission line, the generated data provided to the transmission line being wrapped around back to the first processing device so that the wrapped generated data does not pass through the second processing device, and

a data abnormality monitoring unit which receives the generated data and the wrapped generated data, determines whether the generated data correlates with the wrapped generated data, and determines that an abnormality has occurred in the first processing device when the generated data does not correlate with the wrapped generated data, so that the first processing device determines that an abnormality has occurred without relying on data produced by the second processing device.

34. A method for determining whether an abnormality occurs in data transmitted from a first processing device to a second processing device through a transmission line, the method comprising the steps of:

generating data by the first processing device for transmission to the second processing device;

providing the generated data to the transmission line;

wrapping the generated data provided to the transmission line back to the first processing device so that the wrapped generated data does not pass through the second processing device;

determining whether the generated data correlates with the wrapped generated data;

determining that an abnormality has occurred in the first processing device when the generated data does not correlate with the wrapped generated data, to thereby determine whether an abnormality has occurred in the first processing device without relying on data produced by the second processing device.

35. A computer system having a facility for detection of data abnormalities, provided with a data transmission line and a plurality of data transmission apparatuses connected in common to the data transmission line, wherein each data transmission apparatus is provided with:

a central processing unit for transmission and reception of data with the data transmission line,

a transmission/reception control unit connected with the central processing unit and controlling transmission and reception of the transmission data and received data,

a driver for outputting the transmission data to the data transmission line,

a receiver for receiving as input the data received from the data transmission line, and

a data abnormality monitoring means for receiving as input the data received from the receiver, monitoring the correlation with the transmission data, and, when there is no correlation, determining that an abnormality has occurred in the transmission of the data, wherein;

the data abnormality monitoring means is comprised of a changing point detecting unit which detects the points of change of the input received data, which means determines that an abnormality has occurred in the transmission of data when the number of points of change is less than a predetermined reference value, and

the data transmission apparatus comprises;

a changing point frequency selector for detecting that the number of points of change is less than a predetermined reference value, and

a changing point frequency latch for holding the results of detection by the change point frequency selector and for interrupting the central processing unit.

36. A computer system comprising:

a data transmission line; and

a plurality of data transmissions apparatuses connected in parallel to the data transmission line, each data transmission apparatus generating transmission data and providing the generated transmission data to the data transmission line, the generated transmission data provided to the data transmission line being wrapped around back to the respective data transmission apparatus without passing through any other data transmission apparatus, the wrapped generated transmission data being defined as wrapped data, each data transmission apparatus comprising;

data abnormality monitoring means for receiving the generated transmission data and the wrapped data, and for determining whether the generated transmission data correlates with the wrapped data, wherein it is determined that an abnormality occurred when the generated transmission data does not correlate with the wrapped data, wherein;

each data transmission apparatus further comprises;

a receiver for receiving data from the data transmission line, the wrapped data being received by the receiver from the data transmission line, and the data abnormality monitoring means receiving the wrapped data from the receiver,

the data abnormality monitoring means of each data transmission apparatus further comprises;

a change point detecting unit for detecting points of change of the wrapped data, and for comparing the detected points of change with a reference value, the data abnormality monitoring means determining that the generated transmission data does not correlate with the wrapped data when the number of detected points is less than the reference value,

each data transmission apparatus includes a central processing unit for controlling the data transmission apparatus, and

the data abnormality monitoring means of each data transmission apparatus comprises;

a changing point frequency selector for detecting that the number of points of change is less than a predetermined reference value, and

a changing point frequency latch for holding the result of detection by the change point frequency selector and for interrupting the central processing unit when the result of detection indicates that an abnormality occurred.

37. A data transmission apparatus connected to a data transmission line, the data transmission apparatus comprising:

a data generating device which generates data and provides the generated data to the data transmission line, the generated data provided to the data transmission line being wrapped around back to the data transmission apparatus without passing through any other data transmission apparatuses connected to the data transmission line;

a data abnormality monitoring unit which receives the generated data and the wrapped generated data, determines whether the generated data correlates with the wrapped generated data, and determines that an abnormality has occurred in the data transmission apparatus when the generated data does not correlate with the wrapped generated data, so that the data transmission apparatus determines that an abnormality has occurred without relying on data from another data transmission apparatus connected to the data transmission line; and

a switch which disconnects the data transmission apparatus from the data transmission line when the data abnormality monitoring unit determines that an abnormality has occurred.

38. A data transmission apparatus, connected to a data transmission line, comprising:

a transmission control unit generating transmission data and transmitting the transmission data to the data transmission line, the transmission data being wrapped back to the data transmission apparatus without passing through any other data transmission apparatuses connected to the data transmission line;

a data abnormality monitor detecting abnormalities in the wrapped transmission data without relying on data from another data transmission apparatus connected to the data transmission line; and

a switch disconnecting the data transmission apparatus from the data transmission line when the data abnormality monitor detects an abnormality in the wrapped transmission data.

39. A data transmission apparatus as set forth in claim 38, wherein, after the switch disconnects the data transmission apparatus from the data transmission line, the data abnormality monitor checks for abnormalities in transmission data being generated by the data transmission apparatus after being disconnected, and the switch reconnects the data transmission apparatus to the data transmission line if the check by the data abnormality monitor indicates that there are no abnormalities.

40. A data transmission apparatus as set forth in claim 38, wherein the wrapped transmission data is wrapped by being wrapped back from the data transmission line.