COMPATIBLE VERSION MODULE LOADING

• US 20030159135A1
• Filed: 12/16/1999
• Published: 08/21/2003
• Est. Priority Date: 12/16/1999
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: DONER, DAVID F. Jr., GEE, THOMAS, HILLER, DEAN
• Granted Patent: US 6,658,659 B2
• Time in Patent Office: Days
• US Class Current: 717/166
• CPC Class Codes: G06F 9/44536 Selecting among different versions
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

A system and method for loading software identifies versions of software modules to be loaded. The version identification allows a loader to request, access and load any level or version of a program that the application interacts with. Thus, the loader selects only specific versions of software that are known to be compatible with other software currently loaded or being loaded. The software includes specific compatibility information that is used to determine whether it should be selected or passed over for another version of the same software. In this manner, a “version aware” loader ensures that loaded software modules are compatible with one another and will therefore execute properly. The version aware loader may be implemented in an operating system or other loading software running on a personal computer or network router.

Claims

1. A method of loading a software program into memory, the software program including multiple modules, at least one of which is available in a plurality of versions identified by a set of version numbers, the method comprising:

identifying a module to be loaded as part of the software program, wherein the module is identified, at least in part, by an acceptable version number;

selecting the module based upon an acceptable version number from among the set of versions numbers of the module; and

loading the selected module into memory.

2. The method of claim 1 wherein the plurality of versions of the module share a common name.

3. The method of claim 2 wherein each module sharing the common name has a unique version number within the set of version numbers.

4. The method of claim 2 further including searching for the module in a search path using the common name.

5. The method of claim 2 wherein selecting the module comprises selecting the first module found that has the common name and the acceptable version number belonging to the acceptable version number set.

6. The method of claim 2 wherein the acceptable version number set is identified by a Boolean expression.

7. The method of claim 6 wherein the Boolean expression specifies a group of version numbers that are greater than or equal to a particular version number of the module.

8. The method of claim 7 wherein the particular version number for the module corresponds to a minimum date of release for the module.

9. The method of claim 2, wherein selecting the module based upon an acceptable version number comprises:

finding a potential module in the search path having the common name; and

confirming that the potential module has the acceptable version number.

10. The method of claim 1, further comprising, prior to loading, confirming that the selected module is compatible with any modules that call it.

11. The method of claim 1 wherein loading the module comprises specifying a memory address to be used to access the module for the module during execution.

12. The method of claim 1 wherein the module is included in a component and the component has a set of functionally related modules

13. The method of claim 1 wherein the selected module includes a compatibility vector identifying one or more components to be called by it during execution.

14. The method of claim 13 wherein the compatibility vector further comprises, for each module to be called by the selected module, a compatible version set.

15. The method of claim 1 further including executing the selected module after it has been loaded into memory.

16. The method of claim 1 further including informing a user if no module was found that corresponded to an acceptable version number.

17. A versioned software module capable of being loaded with various combinations of other modules, the software module comprising:

a name in common with at least one module not included in the software program, the module and the at least one module not included in the software program differing by a first version identification included in the module and a second version identification included in the at least one module not included in the software program; and

a compatibility vector including a set of entries, wherein each entry in the set of entries includes (i) the name of a component containing a called module that is called by the versioned software module during execution, and (ii) a compatible version number or group of version numbers for the component containing the called module.

18. The versioned software module of claim 17, wherein the compatible version number or the group of version numbers is expressed as a logical range of version numbers.

19. The versioned software module of claim 18, wherein the logical range is provided in the form of a Boolean expression.

20. The versioned software module of claim 17, further comprising indicia of backward incompatibility with other modules that may call the versioned software module.

21. The versioned software module of claim 17, wherein the name and first version identification are provided in a header of the versioned software module.

22. Loaded executable software comprising at least two separate versioned software modules as recited in claim 17.

23. A computer system capable of loading and executing software, the computer system comprising:

a memory which temporarily stores software modules for execution;

a processor which executes loaded software modules; and

a loader which loads said software modules into the memory, wherein the loader selects at least some software modules for loading based on acceptable version numbers when such modules are available in a plurality of versions identified by a set of version numbers.

24. The computer system of claim 23, further comprising a second memory which stores the software modules, wherein the loader loads the software modules into memory from the second memory prior to execution.

25. The computer system of claim 23, wherein at least some of the software modules selected based on acceptable version numbers share common names with other software modules having different version numbers.

26. The computer system of claim 25, wherein the loader uses the common names to search for the software modules in a search path.

27. The computer system of claim 23, wherein the loader employs Boolean expressions specifying ranges of acceptable version numbers for selecting the software modules to be loaded.

28. The computer system of claim 23, wherein the loader determines whether a software module to be loaded is incompatible with another software module that will call it.

29. The computer system of claim 23, wherein the loader considers a compatibility vector of a software module, wherein the compatibility vector identifies one or more modules to be called by the software module.

30. A computer program product comprising a computer readable medium on which is stored a program instructions for loading a software program into memory, the software program including multiple modules, at least one of which is available in a plurality of versions identified by a set of version numbers, the program instructions comprising:

identifying a module to be loaded as part of the software program, wherein the module is identified, at least in part, by an acceptable version number;

selecting the module based upon an acceptable version number from among the set of versions numbers of the module; and

loading the selected module into memory.

31. The computer program product of claim 30 wherein the plurality of versions of the module share a common name.

32. The computer program product of claim 31 further including instructions for searching for the module in a search path using the common name.

33. The computer program product of claim 31 wherein the acceptable version number set is identified by a Boolean expression.

34. The computer program product of claim 30;

further comprising instructions for confirming, prior to loading, that the selected module is compatible with any modules that call it.

35. The computer program product of claim 30, wherein the selected module includes a compatibility vector identifying one or more modules to be called by it during execution.

36. The computer program product of claim 35, wherein the compatibility vector further comprises, for each module to be called by the selected module, a compatible version set.

37. The computer program product of claim 30, further including instructions for informing a user if no module was found that corresponded to an acceptable version number.

38. A method managing a software environment, the software environment including a plurality of software applications, the plurality of software applications including a module having a common name, the method comprising:

loading a first numbered version of the module having a common name for a first application;

loading a second numbered version of the module having a common name for a second application;

running the first numbered version of the module having a common name; and

running the second numbered version of the module having a common name.

39. A machine readable medium on which is provided a software module available for loading to memory and subsequently executing;

the software module comprising;

a definition section specifying a module name and a version number;

a code section containing program instructions; and

a compatibility vector identifying one or more called modules to be called by the software module during execution, and for each such called module identifying one or more versions of the called module that are compatible with the software module.