Storage control subsystem implemented with an application program on a computer

• US 5,530,845 A
• Filed: 01/17/1995
• Issued: 06/25/1996
• Est. Priority Date: 05/13/1992
• Status: Expired due to Term

• Current Assignee: SBC Technology Resources, Inc. (AT&T, Inc.)
• Original Assignee: Southwestern Bell Technology Resources, Inc. (AT&T, Inc.)
• Inventors: Klos, Timothy R., Hiatt, David M.
• Primary Examiner(s): Lim, Krisna
• Application Number:
  US08/373,896
• Time in Patent Office: 525 Days
• Field of Search: 395/500, 395/882, 395/883
• US Class Current: 703/27
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 13/105 where the programme performs an input/output emulation function
• CPC Class Codes: G06F 13/16 for access to memory bus G06F13/28 takes precedence

Abstract

A storage controller is disclosed which may emulate several types of specialized host specific and/or storage device specific storage controllers. The storage controlling system can transfer information between one or more different types of target units and one or more channels of at least one host. The system is provided with a computer, which includes a first interface, a second interface, and a programmable storage controller. The first interface is configured to receive one or more channel adapters which carry one or more channel programs transmitted from the channels of the host. The channel programs may carry data, status information, and commands. The second interface allows input and output to storage facilities which comprise one or more target units. The programmable storage controller may be provided with a device coupled to the channel adapters for translating channel program commands, and determining, from the channel program, a target unit for which at least one channel program is transmitted. A set of equipment controllers is provided which interpret channel program commands and status information, and which further control data transfers to and from the storage facilities in accordance with the channel program command. A device is also provided for establishing a unit thread by choosing an equipment controller from the set of equipment controllers as a function of the type of equipment that the channel requests as a target.

Claims

1. A storage control subsystem connected between one or more storage controller channels of at least one host system and data storage facilities comprising a plurality of target units, said storage control subsystem comprising:

a programmable storage controller that emulates a plurality of types of target unit specific storage controllers, said programmable storage controller being implemented with an application program and a computer, said computer being configured by said application program;

a first interface for interfacing a plurality of channel adapters which carry a plurality of channel programs transmitted from the channels of the host system to said programmable storage controller, each channel program having means for carrying data, status information and commands; and

a second interface for interfacing said programmable storage controller to said target units;

said programmable storage controller comprising a plurality of controller emulators, said controller emulators comprising means for translating said channel programs and commands from a channel specific format to a generic format of said programmable storage controller that includes generic address and request information, to thereby facilitate data and status command exchanges with said plurality of target units.

2. The storage control subsystem according to claim 1, wherein said programmable storage controller comprises:

means coupled to each said channel adapter for translating channel program commands and determining, from each channel program, a target unit for which at least one channel program command is transmitted;

a set of equipment controllers which interpret channel program commands and status information, and control data transfer to and from said storage facilities in accordance with the channel program commands, each equipment controller comprising means for calling a storage control manager;

means for establishing a unit thread by selecting an equipment controller from said set of controllers, each equipment controller being selected by said means for establishing as a function of the type of equipment that the channel program requests as a target;

means for passing channel program data to said unit thread; and

means for executing said unit thread by executing said equipment controller.

3. The storage control subsystem according to claim 2, wherein said storage control manager comprises a cache manager.

4. The storage control subsystem according to claim 2, wherein said equipment controller further comprises means for prioritizing input and output to and from said storage facilities.

5. The storage control subsystem according to claim 2, wherein each of said channel adapters comprises one or more channel interface circuits, and further wherein said first interface comprises a channel interface controller.

6. The storage control subsystem according to claim 2, wherein the type of equipment for which the host is configured is different than one of said target units.

7. The storage control subsystem according to claim 5, wherein said second interface comprises at least one of a random access and a sequential storage device channel adapter.

8. The storage control subsystem according to claim 7, wherein said storage control subsystem comprises at least one of a random access and a sequential storage device.

9. The storage control subsystem according to claim 8, wherein said storage control subsystem comprises a random access device which comprises a removable direct access storage device.

10. The storage control subsystem according to claim 9, wherein said host system comprises a mainframe computer.

11. The storage control subsystem according to claim 5, wherein said programmable storage controller further comprises a dispatcher for controlling the operation of said programmable storage controller, and further wherein said channel interface controller comprises an interrupt processor, responsive to a command received by each of said channel programs, for interrupting said dispatcher, thus causing said means for executing to execute another unit thread.

12. The storage control subsystem according to claim 11, wherein said channel interface controller further comprises means for controlling said one or more channel interface circuits and means for retrieving at least one of said channel programs.

13. The storage control subsystem according to claim 1, wherein said programmable storage controller further comprises means for signalling that data to be read is compressed, and means for decompressing data.

14. The storage control subsystem according to claim 13, wherein said programmable storage controller further comprises means for signalling that data to be written should be compressed, and means for compressing data.

15. The storage control subsystem according to claim 14, wherein said means for compressing data and said means for decompressing data comprise embedded code.

16. The storage control subsystem according to claim 14, wherein said means for compressing and said means for decompressing comprise parallel RISC processors.

17. The storage control subsystem according to claim 1, wherein said second interface comprises at least one standard high-speed parallel interface.

18. The storage control subsystem according to claim 1, wherein said programmable storage controller further comprises storage control means for receiving and translating the generic address and request information to physical target ID and data address information.

19. The storage control subsystem according to claim 17, wherein said programmable storage controller comprises means for controlling a plurality of different kinds of storage devices which comprise said storage facilities.

20. The storage control subsystem according to claim 1, wherein said programmable storage controller comprises means for accepting and executing storage related commands from host channels having a plurality of different channel languages and dialects.

21. The storage control subsystem according to claim 1, wherein said computer comprises a microcomputer.

22. The storage control subsystem according to claim 1, wherein said computer comprises a personal computer.

23. The storage control subsystem according to claim 1, wherein said computer comprises a tightly coupled multi-processor.

24. The storage control subsystem according to claim 1, wherein said computer comprises a specialized operating system.

25. The storage control subsystem according to claim 1, wherein one of said first and second interfaces further comprises an interface to another storage controller, and further wherein the programmable storage controller comprises a communication bridge for communicating with said another storage controller.

26. The storage control subsystem according to claim 1, wherein said programmable storage controller comprises means for providing a plurality of customized controller services.

27. The storage control subsystem according to claim 26, wherein said means for providing controller services comprise at least one of:

(i) a caching algorithm; and

(ii) means for performing data compression and decompression.

28. The storage control subsystem according to claim 26, wherein said storage control subsystem further comprises said means for providing controller services.

29. The storage control subsystem according to claim 1, wherein said storage control subsystem further comprises said at least one host and said storage facilities.

30. The storage control subsystem according to claim 1, wherein said at least one host system comprises at least one of a mainframe computer, a mini computer, and a micro computer.

31. The storage control subsystem according to claim 2, wherein said equipment controllers comprise one or more reentrant stored programs.

32. The storage control subsystem according to claim 1, wherein said computer comprises a general purpose computer having an operating system comprising means for controlling said general purpose computer.

33. The storage control subsystem according to claim 32, wherein said operating system comprises a standard operating system.

34. A storage controlling method for transferring data between one or more channels of at least one host system and data storage facilities comprising a plurality of different types of target units, said method comprising:

operating a programmable storage controller that emulates a plurality of types of target unit specific storage controllers, said programmable storage controller being implemented with an application program and a computer, said computer being configured by said application program;

receiving a plurality of channel programs transmitted from the channels of the host system, to said programmable storage controller, each channel program carrying at least one of data, status information and commands; and

interfacing said programmable storage controller with said target units; and

controlling, with said programmable storage controller, exchanges of storage data to and from said target units, said controlling comprising translating said channel programs and commands from a channel specific format to a generic format of said programmable storage controller, said generic format including generic address and request information.

35. The storage controlling method according to claim 34, further comprising prioritizing input and output to and from said storage facilities.

36. The storage controlling method according to claim 34, wherein the method further comprises caching data being transmitted to and from said storage facilities.

37. The storage controlling method according to claim 34, wherein interrupt processing is executed responsive to a command received from the at least one host system, thus causing another unit thread to be executed.

38. The storage controlling method according to claim 34, wherein said one or more different types of target units comprise random access and sequential storage devices.

39. The storage controlling method according to claim 34, said method further comprising:

translating channel program commands, and determining from the channel program a target unit for which at least one channel program command is transmitted;

establishing a unit thread by choosing an equipment controlling routine from a set of equipment controlling routines which interpret data control commands and status information and control data transfer to and from storage facilities in accordance with the channel program commands, each equipment controlling routine being chosen as a function of the type of equipment that the channel program requests as a target;

passing channel program data to the unit thread; and

executing the unit thread by executing the chosen equipment controlling routine; and

said method, during execution of said equipment controlling routine, performing storage control management.

40. The storage controlling method according to claim 39, wherein, during execution of said equipment controlling routine, data is transferred to and from at least one of random access and sequential storage devices.

41. The storage controlling method according to claim 40, wherein the data is transferred to and from a random access storage device which comprises a removable direct access storage device, and further wherein the at least one host system comprises a mainframe computer.

42. The storage controlling method according to claim 39, wherein the type of equipment for which the host system is configured is different than said one or more different types of target units.

43. The storage controlling method according to claim 34, wherein said controlling further comprises receiving and translating the generic address and request information to physical target ID and data address information.

44. The storage controlling method according to claim 34, wherein said computer comprises a general purpose computer having an operating system, said operating comprising controlling said general purpose computer with said operating system.

45. A storage control subsystem connected between storage controller channels of at least one host system and data storage facilities comprising a plurality of target units, said storage control subsystem comprising:

a programmable storage controller that emulates a plurality of types of target unit specific storage controllers, said programmable storage controller being implemented with a general purpose computer with a general purpose operating system supporting an application program, said general purpose computer being configured by said application program;

a first interface for interfacing a plurality of channel adapters which carry a plurality of channel programs transmitted from the channels of the host system to said programmable storage controller, each channel program having means for carrying data, status information and commands; and

a second interface for interfacing said programmable storage controller to said target units;

said programmable storage controller comprising a plurality of controller emulators, said controller emulators comprising means for translating said channel programs and commands from a channel specific format to a generic format of said programmable storage controller that includes generic address and request information, to thereby facilitate data and status command exchanges with said plurality of target units.

46. The storage control subsystem according to claim 45, wherein said programmable storage controller further comprises storage control means for receiving and translating the generic address and request information to physical target ID and data address information.

47. A storage controlling method for transferring data between one or more channels of at least one host system and data storage facilities comprising a plurality of different types of target units, said method comprising:

operating a programmable storage controller that emulates a plurality of types of target unit specific storage controllers, said programmable storage controller being implemented with a general purpose computer with a general purpose operating system supporting an application program, said general purpose computer being configured by said application program;

receiving a plurality of channel programs transmitted from the channels of the host system, to said programmable storage controller, each channel program carrying at least one of data, status information and commands; and

interfacing said programmable storage controller with said target units; and

controlling, with said programmable storage controller, exchanges of storage data to and from said target units, said controlling comprising translating said channel programs and commands from a channel specific format to a generic format of said programmable storage controller, said generic format including generic address and request information.

48. The storage controlling method according to claim 47, wherein said controlling further comprises receiving and translating the generic address and request information to physical target ID and data address information.