Extending system of input/output channel

• US 5,845,146 A
• Filed: 09/05/1996
• Issued: 12/01/1998
• Est. Priority Date: 09/05/1995
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Onodera, Osamu
• Primary Examiner(s): Lim, Krisna
• Assistant Examiner(s): OVEDOVITZ, DAVID M
• Application Number:
  US08/670,316
• Time in Patent Office: 817 Days
• Field of Search: 395/822, 395/823
• US Class Current: 710/2
• CPC Class Codes: G06F 13/122 where hardware performs an I/O function other than control of data transfer

Abstract

An extending system in an information processing system which includes an input/output channel and operates a plurality of virtual computers. A plurality of input/output processing units are included in the input/output channel and each virtual computer issues a region ID and a channel path ID. A channel path reconfiguration array is provided having a plurality of channel path reconfiguration array blocks corresponding to region IDs. Each channel path reconfiguration array block includes a plurality of channel path reconfiguration array entries corresponding to channel path IDs and each channel path reconfiguration array entry includes an input/output processing unit number and a channel path ID. A selector is provided for selecting a channel path reconfiguration array block corresponding to the region ID issued by a virtual computer and selecting a channel path reconfiguration array entry corresponding to channel path ID issued by the virtual computer within the selected channel path reconfiguration array block. The virtual computer selects one of the input/output processing units corresponding to the input/output processing number from the selected channel path reconfiguration array entry and accesses the input/output processing circuit using the channel path ID from the selected channel path reconfiguration array entry.

Claims

1. An information processing system including a central processing unit, a memory device and an input/output channel wherein a plurality of virtual computers act on said central processing unit, comprising:

a plurality of input/output processing units included in said input/output channel;

wherein each virtual computer issues a region ID which identifies said virtual computer and a channel path ID which identifies an input/output channel to be used to access one of said input/output processing units;

a channel path reconfiguration array having a plurality of channel path reconfiguration array blocks corresponding to region IDs, each channel path reconfiguration array block comprises a plurality of channel path reconfiguration array entries corresponding to channel path IDs, each channel path reconfiguration array entry having an input/output processing unit number and a channel path ID; and

selecting means for selecting a channel path reconfiguration array block within said channel path reconfiguration array corresponding to said region ID issued by said virtual computer and selecting a channel path reconfiguration array entry corresponding to said channel path ID issued by said virtual computer within the selected channel path reconfiguration array block,

wherein said virtual computer selects one of said input/output processing units corresponding to the input/output processing number from the selected channel path reconfiguration array entry and accesses the input/output processing unit using the channel path ID from the selected channel path reconfiguration array entry.

2. An information processing system according to claim 1, further comprising:

changing means for changing contents of said channel path reconfiguration array in response to a changing demand issued from said virtual computer, wherein said changing means stores an input/output processing unit number and a channel path ID in a channel path reconfiguration array entry of a channel path reconfiguration array block within said channel path reconfiguration array selected by said selecting means based on a region ID and a channel path ID issued by said virtual computer along with said changing demand.

3. An information processing system according to claim 2, further comprising:

wherein said virtual computer issues the region ID and the channel path ID and accesses said input/output processing unit and said input/output processing unit issues an input/output processing unit number and a channel path ID to said virtual computer as a response to an access,

a region ID reconfiguration array having a plurality of region ID reconfiguration array blocks corresponding to input/output processing unit numbers, each region ID configuration block comprises a plurality of region ID reconfiguration array entries corresponding to channel path IDs, each region ID configuration array entry having a region ID and a channel path ID; and

second selecting means for selecting a region ID reconfiguration array block within said region ID reconfiguration array corresponding to an input/output processing unit number issued as a response to an access by said input/output processing unit and selecting a region ID reconfiguration array entry from the selected region ID reconfiguration array block corresponding to the channel ID issued as a response to said access by said input/output processing unit;

wherein one of said input/output processing units corresponding to the input/output processing unit number issues a response to a virtual computer corresponding to the region ID from the selected region ID reconfiguration array entry.

4. An information processing system according to claim 3, further comprising:

second changing means for changing contents of said region ID reconfiguration array in response to a second changing demand issued from said virtual computer,

wherein said second changing means stores a region ID and a channel path ID in a region ID reconfiguration array entry of a region ID reconfiguration array block within said region ID reconfiguration array selected by said second selecting means based on an input/output processing unit number and a channel path ID issued by said virtual computer along with said second changing demand.

5. An information processing system according to claim 4, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

6. An information processing system according to claim 5, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

7. An information processing system according to claim 4, wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

8. An information processing system according to claim 7, further comprising:

means for, when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response and, when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

9. An extending system according to claim 8, further comprising:

changing means for changing contents of said channel path reconfiguration array in response to a changing demand issued from said virtual computer,

wherein said changing means stores an input/output processing unit number and a channel path ID in a channel path reconfiguration array entry of a channel path reconfiguration array block within said channel path reconfiguration array selected by said selecting means based on a region ID and a channel path ID issued by said virtual computer along with said changing demand.

10. An extending system according to claim 9, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

11. An extending system according to claim 10, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

12. An extending system according to claim 8, further comprising:

wherein said virtual computer issues the region ID and the channel path ID and accesses said input/output processing unit and said input/output processing unit issues an input/output processing unit number and a channel path ID to said virtual computer as a response to an access,

a region ID reconfiguration array having a plurality of region ID reconfiguration array blocks corresponding to input/output processing unit numbers, each region ID configuration block comprises a plurality of region ID reconfiguration array entries corresponding to channel path IDs, each region ID configuration array entry having a region ID and a channel path ID; and

second selecting means for selecting a region ID reconfiguration array block within said region ID reconfiguration array corresponding to an input/output processing unit number issued as a response to an access by said input/output processing unit and selecting a region ID reconfiguration array entry from the selected region ID reconfiguration array block corresponding to the channel ID issued as a response to said access by said input/output processing unit;

wherein one of said input/output processing units corresponding to the input/output processing unit number issues a response to a virtual computer corresponding to the region ID from the selected region ID reconfiguration array entry.

13. An extending system according to claim 12, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

14. An extending system according to claim 13, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

15. An extending system according to claim 12, further comprising:

changing means for changing contents of said region ID reconfiguration array in response to a changing demand issued from said virtual computer,

wherein said changing means stores a region ID and a channel path ID in a region ID reconfiguration array entry of a region ID reconfiguration array block within said region ID reconfiguration array selected by said second selecting means based on an input/output processing unit number and a channel path ID issued by said virtual computer along with said changing demand.

16. An extending system according to claim 15, wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

17. An extending system according to claim 16, further comprising:

means for, when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response and, when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

18. An extending system according to claim 15, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

19. An extending system according to claim 18, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

20. An extending system according to claim 12, wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

21. An extending system according to claim 20, further comprising:

means for, when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response and, when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

22. An information processing system according to claim 3, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

23. An information processing system according to claim 22, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

24. An information processing system according to claim 3, wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

25. An information processing system according to claim 24, further comprising:

means for, when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response and, when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

26. An information processing system according to claim 2, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

27. An information processing system according to claim 26, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

28. An information processing system according to claim 1, further comprising:

wherein said virtual computer issues the region ID and the channel path ID and accesses said input/output processing unit and said input/output processing unit issues an input/output processing unit number and a channel path ID to said virtual computer as a response to an access,

a region ID reconfiguration array having a plurality of region ID reconfiguration array blocks corresponding to input/output processing unit numbers, each region ID configuration block comprises a plurality of region ID reconfiguration array entries corresponding to channel path IDs, each region ID configuration array entry having a region ID and a channel path ID; and

second selecting means for selecting a region ID reconfiguration array block within said region ID reconfiguration array corresponding to an input/output processing unit number issued as a response to an access by said input/output processing unit and selecting a region ID reconfiguration array entry from the selected region ID reconfiguration array block corresponding to the channel ID issued as a response to said access by said input/output processing unit;

wherein one of said input/output processing units corresponding to the input/output processing unit number issues a response to a virtual computer corresponding to the region ID from the selected region ID reconfiguration array entry.

29. An information processing system according to claim 28 wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

30. An information processing system according to claim 29, further comprising:

means for, when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response and, when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

31. An information processing system according to claim 28, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

32. An information processing system according to claim 31, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

33. An information processing system according to claim 28, further comprising:

changing means for changing contents of said region ID reconfiguration array in response to a changing demand issued from said virtual computer,

wherein said changing means stores a region ID and a channel path ID in a region ID reconfiguration array entry of a region ID reconfiguration array block within said region ID reconfiguration array selected by said second selecting means based on an input/output processing unit number and a channel path ID issued by said virtual computer along with said changing demand.

34. An information processing system according to claim 33, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

35. An information processing system according to claim 34, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

36. An information processing system according to claim 33, wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

37. An information processing system according to claim 36, further comprising:

means for, when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response and, when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

38. An information processing system according to claim 1, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

39. An information processing system according to claim 38, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

40. An extending system for extending an input/output channel of an information processing system, wherein a plurality of virtual computers are operated on said information processing unit, wherein a plurality of input/output processing units are included in said input/output channel, and wherein each virtual computer issues a region ID which identifies a virtual computer and a channel path ID which identifies an input/output channel to be used to access one of said input/output processing units, said extending system comprising:

a channel path reconfiguration array having a plurality of channel path reconfiguration array blocks corresponding to region IDs, each channel path reconfiguration array block comprises a plurality of channel path reconfiguration array entries corresponding to channel path IDs, each channel path reconfiguration array entry having an input/output processing unit number and a channel path ID; and

selecting means for selecting a channel path reconfiguration array block within said channel path reconfiguration array corresponding to said region ID issued by said virtual computer and selecting a channel path reconfiguration array entry corresponding to said channel path ID issued by said virtual computer within the selected channel path reconfiguration array block,

wherein said virtual computer selects one of said input/output processing units corresponding to the input/output processing number from the selected channel path reconfiguration array entry and accesses the input/output processing unit using the channel path ID from the selected channel path reconfiguration array entry.

41. An extending system according to claim 40, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

42. An extending system according to claim 41, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

43. An extending system according to claim 40, further comprising:

wherein said virtual computer issues the region ID and the channel path ID and accesses said input/output processing unit and said input/output processing unit issues an input/output processing unit number and a channel path ID to said virtual computer as a response to an access,

a region ID reconfiguration array having a plurality of region ID reconfiguration array blocks corresponding to input/output processing unit numbers, each region ID configuration block comprises a plurality of region ID reconfiguration array entries corresponding to channel path IDs, each region ID configuration array entry having a region ID and a channel path ID; and

second selecting means for selecting a region ID reconfiguration array block within said region ID reconfiguration array corresponding to an input/output processing unit number issued as a response to an access by said input/output processing unit and selecting a region ID reconfiguration array entry from the selected region ID reconfiguration array block corresponding to the channel ID issued as a response to said access by said input/output processing unit;

wherein one of said input/output processing units corresponding to the input/output processing unit number issues a response to a virtual computer corresponding to the region ID from the selected region ID reconfiguration array entry.

44. An extending system according to claim 43, wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

45. An extending system according to claim 44, further comprising:

means for, when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response and, when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

46. An extending system according to claim 43, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

47. An extending system according to claim 46, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

48. An extending processing system according to claim 43, further comprising:

second changing means for changing contents of said region ID reconfiguration array in response to a second changing demand issued from said virtual computer,

wherein said second changing means stores a region ID and a channel path ID in a region ID reconfiguration array entry of a region ID reconfiguration array block within said region ID reconfiguration array selected by said second selecting means based on an input/output processing unit number and a channel path ID issued by said virtual computer along with said second changing demand.

49. An extending system according to claim 48, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

50. An extending system according to claim 49, further comprising:

means for, when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel and, when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

51. An extending system according to claim 48, wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

52. An extending system according to claim 51, further comprising:

means for, when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response and, when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

53. A method of extending an input/output channel of an information processing system, wherein a plurality of virtual computers are operated on said information processing unit, wherein a plurality of input/output processing units are included in said input/output channel, and wherein each virtual computer issues a region ID which identifies a virtual computer and a channel path ID which identifies an input/output channel to be used to access one of said input/output processing units, said method comprising the steps of:

selecting a channel path reconfiguration array block within a channel path reconfiguration array corresponding to said region ID issued by said virtual computer;

selecting a channel path reconfiguration array entry corresponding to said channel path ID issued by said virtual computer within the selected channel path reconfiguration array block;

selecting one of said input/output processing units corresponding to an input/output processing number included in the selected channel path reconfiguration array entry; and

accessing the input/output processing unit using a channel path ID included in the selected channel path reconfiguration array entry.

54. A method according to claim 53, further comprising the steps of:

changing contents of said channel path reconfiguration array in response to a changing demand issued from said virtual computer; and

storing an input/output processing unit number and a channel path ID in a channel path reconfiguration array entry of a channel path reconfiguration array block within a selected channel path reconfiguration array corresponding to a region ID and a channel path ID issued by said virtual computer along with said changing demand.

55. A method according to claim 54, wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

56. A method according to claim 55, further comprising the steps of:

when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response; and

when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

57. A method according to claim 54, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

58. A method according to claim 57, further comprising the steps of:

when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel; and

when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

59. A method according to claim 54, further comprising the steps of:

changing contents of said region ID reconfiguration array in response to a changing demand issued from said virtual computer; and

storing a region ID and a channel path ID in a region ID reconfiguration array entry of a region ID reconfiguration array block within a selected region ID reconfiguration array corresponding to an input/output processing unit number and a channel path ID issued by said virtual computer along with said changing demand.

60. A method according to claim 59, wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

61. A method according to claim 60, further comprising the steps of:

when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response; and

when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

62. A method according to claim 59, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

63. A method according to claim 62, further comprising the steps of:

when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel; and

when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

64. A method according to claim 54, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

65. A method according to claim 64, further comprising:

when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel; and

when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

66. A method according to claim 53, further comprising the steps of:

wherein said virtual computer issues the region ID and the channel path ID and accesses said input/output processing unit and said input/output processing unit issues an input/output processing unit number and a channel path ID to said virtual computer as a response to an access,

selecting a region ID reconfiguration array block within a region ID reconfiguration array corresponding to an input/output processing unit number issued as a response to an access by said input/output processing unit;

selecting a region ID reconfiguration array entry from the selected region ID reconfiguration array block corresponding to a channel ID issued as a response to said access by said input/output processing unit; and

issuing by one of said input/output processing units corresponding to said input/output processing unit number a response to a virtual computer corresponding to a region ID included in the selected region ID reconfiguration array entry.

67. A method according to claim 66, wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

68. A method according to claim 67, further comprising the steps of:

when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response; and

when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

69. A method according to claim 66, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

70. A method according to claim 69, further comprising the steps of:

when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel; and

when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

71. A method according to claim 66, further comprising the steps of:

changing contents of said region ID reconfiguration array in response to a second changing demand issued from said virtual computer; and

storing a region ID and a channel path ID in a region ID reconfiguration array entry of a region ID reconfiguration array block within a selected region ID reconfiguration array corresponding to an input/output processing unit number and a channel path ID issued by said virtual computer along with said second changing demand.

72. A method according to claim 71, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

73. A method according to claim 72, further comprising the steps of:

when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel; and

when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.

74. A method according to claim 71, wherein each region ID reconfiguration array entry includes a validity display field indicating whether the region ID reconfiguration array entry is valid or invalid, a region ID field storing a region ID and a channel path ID field storing a channel path ID.

75. A method according to claim 74, further comprising the steps of:

when the validity display field of a selected region ID reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output processing unit issuing the response; and

when the validity display field indicates validity, selecting a virtual computer corresponding to the region ID of the region ID field and conducting a response to the selected virtual computer by the channel path corresponding to the channel path ID of the channel path ID field.

76. A method according to claim 53, further comprising the steps of:

wherein said virtual computer issues the region ID and the channel path ID and accesses said input/output processing unit and said input/output processing unit issues an input/output processing unit number and a channel path ID to said virtual computer as a response to an access,

selecting a region ID reconfiguration array block within a region ID reconfiguration array corresponding to an input/output processing unit number issued as a response to an access by said input/output processing unit; and

selecting a region ID reconfiguration array entry from the selected region ID reconfiguration array block corresponding to a channel ID issued as a response to said access by said input/output processing unit; and

issuing by one of said input/output processing units corresponding to said input/output processing unit number a response to a virtual computer corresponding to a region ID included in the selected region ID reconfiguration array entry.

77. A method according to claim 53, wherein each channel path reconfiguration array entry includes a validity display field indicating whether the channel path reconfiguration array entry is valid or invalid, an input/output processing unit number field for storing an input/output processing unit number and a channel path ID field for storing a channel path ID.

78. A method according to claim 77, further comprising the steps of:

when the validity display field of a selected channel path reconfiguration array entry indicates invalidity, reporting a condition code that a channel path ID associated with the access is not provided to the input/output channel; and

when the validity display field indicates validity, selecting an input/output processing unit based on the input/output processing unit number of the input/output processing unit number field of the selected channel path reconfiguration array entry and accessing the selected input/output processing unit by the channel path ID from the channel path ID field of the selected channel path reconfiguration array entry.