Abstract:
A tool is provided for addressing a number of issues related to providing support for software stacks including multiple uncoordinated components such as open source projects. The tool receives information about a stack, obtains support information specific to that stack and outputs the information to a user. A parsing functionality is also provided for selectively combining support information from the constituent projects of the stack.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 11/118,101, entitled “Post-Installation Tools for Software Stacks,” which was filed on Apr. 28, 2005 now U.S. Pat. No. 7,657,866 and claims priority from U.S. Patent Application Ser. No. 60/566,310, entitled “Open Source Application Development Tools” filed Apr. 28, 2004, U.S. Patent Application No. 60/566,301, entitled “Open Source Software Package Installation” filed Apr. 28, 2004, and U.S. Patent Application Ser. No. 60/566,311, entitled “Post Installation Tools for Open Source Application Development Packages” filed on Apr. 28, 2004, which are hereby incorporated by reference into this application. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates in general to software projects including open source projects or projects that are otherwise available for stacking and, in particular, to a tool for assembling, installing and supporting or servicing software stacks. 
     BACKGROUND OF THE INVENTION 
     Conventionally, packages of software have been formed from proprietary applications. These applications have generally been provided by a single source or by industry partners such that the applications have been developed in a coordinated way to facilitate such packaging. However, the assembly and use of such packages has generally been limited by associated licenses. More recently, open source software has grown rapidly in importance and availability. Generally, open source software is software where the source code is available for copying and modification and whose licenses generally give the user freedom to use the software for any purpose as well as to modify and redistribute the software. In this regard, open source software is distinguished from proprietary software in that the source code of proprietary software is generally not made available to the end user and the licenses for proprietary software generally place significant restrictions on use, copying, modification and redistribution. In addition, open source software is generally made available for free or for a reasonable reproduction fee whereas proprietary software is frequently provided on a for profit basis. 
     Open source software has a number of potential advantages for end users. First, because the source code is available to the end user and the licenses allow for substantial freedom of use and modification, the end user has significant flexibility to adapt and optimize the code for a particular endeavor. In this regard, the end user is not tied into a particular proprietary system. In addition, studies have shown that open source software tends to be of very high quality. That is, due to the open nature of the software and the opportunity for virtually unlimited peer review, the open source software is generally continually improving in quality. Moreover, because the open source software is generally available for free or at a nominal cost, there is a significant potential to use the open source software in a cost effective manner. For these and other reasons, many governments and other entities have mandated or encouraged a transition from proprietary software to open source software for systems under their control. 
     At the present time, however, significant obstacles remain with respect to fully realizing the potential advantages of open source software or other independently developed or uncoordinated software. One such challenge is assembling software stacks. Typically, a software system, application or tool (“project”) does not function in isolation. Rather, a particular project may require another project (e.g., open source or proprietary) as a prerequisite to its proper operation and, once installed, may be used by other projects. Because of these vertical dependency relationships, end users often require or desire a software stack including multiple projects. Assembling such stacks involves identifying individual projects required for an endeavor as well as addressing the dependency relationships. This may require significant expertise and time. Although some open source providers offer coordinated projects or stacks, open source software tends to be uncoordinated. 
     Another difficulty associated with the use of uncoordinated software such as certain open source software relates to installation. Installation involves addressing various machine configuration issues, integrating software projects, resolving conflicts and testing for proper interoperation of the individual projects as well as interoperation between the projects and machine components. Again, installation often requires significant expertise and time. 
     In addition, there are a number of post-installation issues relating to the use of such uncoordinated software. For example, the use of any software may require occasional reference to user manuals and other documentation. Such documentation may not be readily available in the context of a stack including multiple uncoordinated (e.g., open source). Even when documentation is available for individual projects, such documentation may not be adapted for the environment of a particular software stack. Similarly, training materials such as tutorials may not be available or optimized for a software stack environment. Other post-installation issues relate to uninstalling projects or altering installed projects or stacks. 
     SUMMARY OF THE INVENTION 
     The present invention relates to assembling, installing and supporting or servicing software stacks composed of multiple projects, including uncoordinated projects. The projects are software components for particular applications such as proprietary software applications and open source projects. A stack is defined by installing two or more projects in a processing environment (single machine or distributed) such that the projects share one or more logical resources such as a function library or are otherwise configured for cooperative and dependent operation. That is, two projects have a dependency relationship where a first one of the projects requires a project, such as the other (second) one of the projects, to perform a function that defines a substantial part of the first project&#39;s application. The projects are thus vertically integrated. In this regard, uncoordinated projects are projects that are not specifically preconfigured for such cooperative and dependent operation in a stack. For example, such projects may be developed by multiple parties working independently or by open source developers. 
     In particular, the present invention is directed to a tool for addressing a number of the above-noted issues relating to software stacks including multiple uncoordinated components. The tool facilitates stack assembly by identifying individual projects, managing dependency relationships and providing an intuitive graphical interface to assist the user. In addition, the tool facilitates installation by addressing machine configuration issues, resolving conflicts and performing at least partially automated testing. The tool also addresses a number of post-installation issues including the generation of appropriate documentation and training tools, as well as by facilitating de-installation of projects as well as modification of replacement projects and software stacks. 
     In accordance with one aspect of the present invention, a method and apparatus (collectively, “utility”) is provided for enabling convenient access to stacks of uncoordinated software projects. Specifically, the utility involves receiving an input regarding a stack of interest, accessing information regarding potential stacks and outputting stack information responsive to the input. From the perspective of a user or user system, the utility involves accessing a system for providing stack information regarding stacks of (formed from) uncoordinated software projects, submitting an input (e.g., to a local processor or remote platform) regarding a stack of interest and receiving stack information responsive to the input. The stack information may include, for example, an identification of the project content of one or more possible stacks, projects for installation as one or more stacks, and/or installation information for one or more possible stacks. In this regard, for example, a stack or information defining a stack may be assembled from projects or project information responsive to the input, or such stacks or information defining stacks may be predetermined and stored. That is, the stack information can be assembled at various times and in various ways. In any event, convenient access can be provided to information useful in assembling and/or installing stacks formed from uncoordinated software projects, e.g., including one or more open source projects. 
     In accordance with another aspect of the present invention, a utility is provided for use in assembling stacks of software projects. That is, the utility is useful in determining the project content of a stack. It will be appreciated the utility may further be useful in identifying and/or resolving conflicts, dependency characteristics and other issues relating to assembling a stack. The utility involves operating a computer based tool to receive input information regarding a stack of interest, determine at least a first characteristic of a first project of the stack, and provide information regarding a second project of the stack. The input information may, for example, identify a function of this stack, identify the first project for inclusion in the stack or otherwise provide initial information for use in assembling the stack. 
     Based on this input information, the computer based tool is operative to determine the first characteristic of the first project. The first characteristic may relate, for example, to a dependency relationship of the first project or a resource requirement. In this regard, the computer based tool may identify one or more projects on which the first project depends, one or more projects having a dependency that is satisfied by the first project or may relate to ports or other resource requirements. This characteristic is used to provide information regarding a second project of this stack. Thus, for example, dependency relationships, conflicts and the like may be identified in an output to the user or resolved so as to assist in stack assembly. For example, one or more graphical user interfaces may identify dependencies or conflicts to resolve in order to complete a desired stack assembly. 
     The utility can be used to facilitate assembly of uncoordinated projects. In this regard, the first and second projects may be uncoordinated and may include open source projects, proprietary projects, other projects or combinations thereof. Preferably, at least one of the projects in the stack operates at a tools or applications layer of the stack above an operating system level of the stack. 
     According to another aspect of the present invention, a utility is provided for use in assembling stacks by reference to a knowledge base including information regarding a set of supported projects and dependency information. Specifically, the utility involves identifying a set of software projects and determining, for the set of software projects, a set of dependency relationships relating to interoperation of the software projects. A controller includes logic for accessing information reflecting the dependency relationships and relating particular ones of the software projects based on the dependency relationships. In operation, the controller receives a user input indicating an interest in assembling a stack of projects and identifying, at least by type, at least a first project for inclusion in this stack. Based on this user input and the dependency relationships, the controller identifies at least a second project for inclusion in the stack. For example, a user may indicate a particular function to be performed by the stack or a particular project that the user is interested in using. In the case of an identified function, the controller may identify project options associated with the function from which the user can select a desired project. In any case, once a project is identified, the stored dependency relationships can be used to identify prerequisite projects, projects used by the first project and further associated dependencies. It will be appreciated that such dependency relationships may exist between first and second groups of programs. In that case, each group effectively functions as a project and the assembly of the groups defines a stack. In this manner, the user can efficiently assemble a stack where dependency relationships are satisfied across the stack. 
     According to a still further aspect of the present invention, a utility is provided for filtering projects in connection with a request to access or use projects. It has been recognized that the ready availability of externally developed projects is problematic for many entities. In particular, in the context of open source projects, such projects are readily available at no or a nominal cost. As a result, personnel may sometimes access such projects without consideration of compliance with license terms or company policy. Moreover, as noted above, open source licenses can include a variety of terms and obligations regarding reproduction or use of the open source software. In many cases, entities may be unaware that such open source projects are being used until undesired consequences have occurred. Accordingly, it would be desirable to provide a tool to assist such entities in facilitating compliance with policies developed by the entity in this regard. 
     An associated utility in accordance with the present invention involves defining filter criteria relating to access or use of software projects, receiving a request for access to or use of one or more software projects and operating a computer based tool to process the request in accordance with the filter criteria to provide an output responsive to the request. The filter criteria reflect a policy affecting the requestor independent of any rights granted by the providers of the software projects or lack thereof. Thus, for example, the filter criteria may define what projects may be accessed, by whom, and for what purpose. For example different criteria may apply to different personnel (e.g., software developers, IT personnel, accounting) and for different purposes (strictly internal use versus incorporation into product). The filter may be implemented in connection with a stack assembly and installation tool. In this regard, graphical user interfaces may only present project options that are appropriate for the person or purpose at issue or filtered projects may be otherwise unavailable for selection in connection with such user interfaces. In this manner, adherence to the entity&#39;s policy concerning projects may be enforced. Projects may be filtered, for example, on a project-by-project basis, based on a type of or category of the projects, or based on a license association of the project. 
     In accordance with a still further aspect of the present invention, a utility is provided for installing uncoordinated software. An associated system involves a configuration module for configuring a number of uncoordinated software projects into a stack and an installer for installing the stack on a computer. For example, the configuration module may configure the projects into a stack responsive to a request from a user or a user system. In this regard, such a stack may be identified with the aid of an assembly tool as discussed above. Alternatively, the projects may be configured into a stack prior to handling a specific request. Preferably, the stack is configured in a manner that resolves dependency issues with respect to the included projects. In addition, the configuration module may take into account the state of the machine on which the stack is to be installed in connection with considering such dependency issues or resolving potential conflicts. From the perspective of a user or user system, the utility involves submitting input information regarding a stack of interest to a configuration module and receiving installation information. Such installation information may include, for example, information regarding an installation procedure, projects reflecting a configuration for use in the stack and/or installation tools. The utility thus addresses a number of problematic issues relating to installation of stacks formed from uncoordinated projects. 
     In accordance with a still further aspect of the present invention, a utility is provided for use in installing a stack of uncoordinated projects on a machine or other system designated by a user. An associated installer may be resident on the designated system or interconnected to a system via a LAN or WAN. In addition, the installer may be operatively associated with an assembly utility as described above or may operate independently. The installer utility is operative to receive input information regarding a stack of interest, determine at least a first characteristic of a first project of the stack, and provide information regarding a second project of the stack. The input information may, for example, identify a function of the stack or identify the first project, at least by type. In response to this information, the utility may identify one or more projects having a dependency relationship with the first project or a resource requirement of the first project. Since such information may be used to identify the second project so as to resolve a dependency relationship or avoid a resource conflict. The utility is useful for installing stacks including uncoordinated projects (e.g., open source projects) where at least one of the projects operates at a tools or applications layer of a stack above an operating system level. 
     In accordance with another aspect of the present invention, a utility is provided for assisting with post-installation support in connection with an installed stack of uncoordinated projects. This support utility may be provided in conjunction with assembly and/or installation utilities as noted above or independently. Moreover, the support utility may operate in connection with a local system or may be accessed via a network, e.g., the Internet. The support utility involves receiving an identification of a stack including a number of uncoordinated software projects, selectively accessing storage to obtain support information specific to that stack and outputting the support information to a user. The support information may include, for example, a tutorial or documentation specifically tailored for the package. Support information may be preassembled and indexed to the stack or may be stored as separate chunks of information that are assembled in response to a request. In this regard, documentation may be stored as structured content, e.g., associated with metadata such as XML tags, identifying a context or association of the data, for example, an association with a particular project. Text and/or graphics may be assembled in this regard. In addition, the support information may be selected based on operating environment information for the stack such as information relating to the machine of a user or operating system of a user. 
     In accordance with yet another aspect of the present invention, a utility is provided for managing updates in connection with an installed stack of uncoordinated projects. It will be appreciated that updates relating to a stack such as project updates, dependency updates and support information updates may become available from time to time. Managing such updates can be problematic, particularly in the context of stacks of uncoordinated software projects. The utility of the present invention involves receiving information regarding the availability of an update concerning a stack, identifying a stack potentially affected by the update, and providing update information to a user or user system. The update information may include, for example, a notification to a user that updates are available, updated software and/or installation information. In this regard, an update may be automatically installed or installed upon receiving an indication from a user that the update is desired. Preferably, update installations are accomplished while leaving at least a portion of the previously installed stack in an installed state, e.g., without uninstalling one or more projects of the stack. An associated update installation process may involve determining an installation sequence, resolving any dependency or resource conflicts, performing an installation of the update in accordance with the determined installation procedure and testing the update upon installation. Associated support materials may also be made available in connection with the update. 
     In accordance with a further aspect of the present invention, a utility is provided for enabling substitution of projects within a stack of software projects. The utility involves receiving an input in relation to an installed stack including a plurality of software projects and, in response to the input, substituting for a first one of the projects a substituted project having substantially equivalent functionality. It will be appreciated that this utility is particularly, though not exclusively, useful in connection with open source projects that often have licensing terms that provide significant flexibility in configuring stacks. For example, the utility may be used to substitute a second database project in place of a first database project in a given stack. In this manner, a user can experiment with different projects to build a stack with optional performance for a given endeavor. 
     In accordance with yet another aspect of the present invention, a utility is provided for managing licensed information. The utility involves storing public information and private information concerning a given software license; providing access to at least a portion of the public information; receiving a request for access to the private information; responsive to the request, verifying an authorization to access the private information, and selectively providing access to the private information based on the verification. For example, in connection with a request to access the private information, a user may be prompted to enter a password or other authorization information. Such authorization information may be used to encrypt and decrypt the private information so as to inhibit unauthorized accesses to such information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention and further advantages thereof, reference is now made to the following detailed description taken in conjunction with the drawings, in which: 
         FIG. 1  is a graph illustrating the layers of an application development environment; 
         FIG. 2  illustrates examples of proprietary applications at various layers of the application development environment; 
         FIG. 3  illustrates the layers of an application development environment including open source options; 
         FIG. 4  illustrates certain dependency relationships of projects in an application development environment; 
         FIG. 5  is a schematic diagram of a software stack assembly, installation and support system in accordance with the present invention; 
         FIGS. 6-11  are examples of user interface screens that may be provided in connection with operation of the system of  FIG. 5 ; 
         FIG. 12  is a schematic diagram illustrating a project filter system in accordance with the present invention; 
         FIG. 13  is a flow chart illustrating the operation of the project filter system of  FIG. 12 ; 
         FIG. 14  is a schematic diagram of a license management system in accordance with the present invention; and 
         FIG. 15  is a flow chart illustrating a stack assembly process in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description, the invention is set forth in the context of a graphical installer system that encompasses stack assembly, installation and support functionality. It should be appreciated that, as noted above, such functionality may be provided independently, rather than as part of an integrated system, in accordance with the present invention. Moreover, it will be appreciated that various aspects of the invention have application beyond the specific context described below. Accordingly, this description should be understood as exemplifying the invention, and not by way of limitation. 
     In the following description, the application development environment is first described in relation to the open source software movement. This represents an illustrative application of stacking uncoordinated projects. Thereafter, a system architecture in accordance with the present invention is described. Finally, specific functionality for stack assembly, installation and post-installation support is described in detail. 
     I. The Open Source Application Development Environment 
     The present invention is directed to a tool for use in assembling, installing and supporting software stacks including, for example, stacks that include one or more open source projects. As noted above, stacks including open source projects are particularly apt for illustrating the various aspects of the present invention, as open source projects are typically uncoordinated and are typically associated with licenses that provide significant freedom for configuration in custom stacks. Indeed, the flexibility to modify and combine such projects as desired is a principal motivation for the open software movement. However, it will be appreciated that stacks may be formed from proprietary applications or a combination of open source projects, proprietary applications and other uncoordinated projects where licenses allow. Indeed, it is anticipated that such combinations will become increasingly common. In any event, the invention has particular advantages in the context of forming stacks of uncoordinated software components, i.e., projects or applications that are not preconfigured to share logical resources such as function libraries or otherwise specifically configured for cooperative and dependant operation in a stack. 
     In the examples below, such stacks are described in the context of an application development environment. In this regard, an application development environment refers to a stack that includes at least one project, that is, an application or a development environment tool, operating above the operating system or hardware levels. This may be understood by reference to  FIG. 1 . As shown in  FIG. 1 , a full software development environment  100  generally includes an applications layer  102 , a development environment tool layer  104 , an operating system layer  106  and a hardware layer  108 . Generally, applications  102  are created by using development tools  104  in a working development environment based on a selected software operating system  106  that functions on selected hardware  108 . 
     Operating system software and development tools have historically been sold by competing commercial vendors and the software is proprietary.  FIG. 2  illustrates a proprietary software development environment  200  with examples of proprietary products at each layer. As shown, the application layer  202  includes various commercially available web-based applications, business applications and other applications. At the development environment tool layer  204 , commercially available tools are provided by Oracle, BEA, Rational and others. The dominant systems at the operating system layer  206  are Windows and Unix, though others are available. Examples of manufacturers at the hardware layer  208  include IBM, Apple, Sun, HP/Compact and Intel. 
     It will be appreciated that there is generally limited flexibility relating to integrating stacks for the software development environment. More specifically, existing operating systems provide an open platform by which particular products can operate independent of the specific hardware environment to a significant degree. Moreover, many products can operate across multiple operating systems. However, at the application layer  202  and development environment tool layer  204 , options are much more limited. Some commercial software developers provide integrated stacks of multiple proprietary products or provide individual products that can be readily integrated into a stack. Similarly, integrated open source stacks or coordinated open source projects are provided by some software developments. These products are developed much like the corresponding proprietary products but have open source rather than proprietary license associations. However, these commercial developers generally have little incentive to accommodate interoperation with respect to products of competing commercial developers. Accordingly, such stacks may be limited to products of a particular commercial developer or a developer and industry partners. Accordingly, an end user has limited flexibility and may be locked into an overall stack environment due to a need for a particular product. 
     Open source software, particularly Linux, has become widely adopted for the operating system layer. In addition, open source development tools and applications are emerging.  FIG. 3  illustrates an open source application development environment  300 . That is, the open source application development environment  300  includes at least one open source project at the application layer  302  and/or development environment tool layer  304 . Proprietary applications may also be available and utilized at these layers in the environment  300 . As shown, an example of an open source application at the application layer  302  is OpenOffice. At the development environment tool layer  304 , examples of open source tools include Eclipse, MySQL and Apache. The illustrated environment  300  includes, at the operating system layer  306 , one example of an open source operating system (Linux) and one example of a proprietary operating system (Unix). At the hardware layer  308 , a number of proprietary original equipment manufacturers are identified. It will thus be appreciated that a full open source application development environment may include or support or allow for proprietary elements, at the operating system and hardware layers  306  and  308  and at the development environment and application layers  302  and  304 . 
     As noted above, while many high quality open source projects are available, there are a number of difficulties associated with the stacking of multiple open source projects (alone or together with proprietary products) to enable a full application development environment. This is graphically illustrated in  FIG. 4 .  FIG. 4  illustrates a number of open source projects and proprietary products. The lines and arrow connecting the various components represent mandatory and conditional dependency relationships such as prerequisites and projects that may be used by another project once installed. A thorough understanding of these dependency relationships as well as a machine state is often necessary to assemble an appropriate stack for a particular endeavor. 
     Moreover, considerable expertise and time may be required for installation of a stack once assembled. For example, installation issues may involve determining a proper installation sequence, addressing various hardware issues, resolving conflicts and testing an installed stack, for example, to determine that required files are accessible. Post-installation issues involve providing appropriate training tools and documentation as well as facilitating the installation and modification of particular projects as well as stacks. These issues are addressed by a system according to the present invention as described below. 
     II. System Architecture 
       FIG. 5  illustrates a software stack assembly, installation and support system  500  in accordance with the present invention. The system  500  is operative to allow a user, operating a user machine  502  such as a personal computer or other processor or processing network, to identify open source (and/or other) software projects for assembly into a stack, to integrate the projects and install them on the user machine  502 , and to generate documentation and training materials specifically related to the stack. The system  500  provides certain additional functionality, such as switching databases or other tools within the stack, e.g., to achieve optimized performance for a particular endeavor. It will be appreciated that such functionality generally is not supported within proprietary or other coordinated software contexts, where the integrating entity usually has a vested interest in commercializing particular software products, nor is such functionality supported within current uncoordinated open source contexts, where stack assembly, integration and installation has generally been performed on a customized endeavor-by-endeavor basis. 
     The illustrated system  500  includes a knowledge base  504  that stores and provides knowledge required for the noted open source stack functionality and an engine  506  that provides the logic for executing such functionality. The knowledge base  504  and engine  506  may be resident on the user machine  502 , or may be at least partially accessible to the user machine  502  via a network such as a WAN, e.g., the internet. Moreover, the knowledge base  504  and engine  506  may be resident on a single processing platform, or a distributed architecture may be employed. 
     The illustrated knowledge base  504  includes, for each supported project, project information  504 A such as identification information and legal information, operational information, and category information. The knowledge base also includes certain machine state information  504 B regarding the user machine  502 . In addition, the knowledge base includes certain stack information  504 C for use in executing functionality at the stack level, such as testing information. 
     With regard to project information  504 A, the information that may be included in the knowledge base  504  to identify a given project may include the project name, version, type, home URL, categories, description (with comparisons and recommendations) and links to full project details. The legal information will generally include any licenses with full license text or links thereto. Such license information provides important legal information to users and further supports license filter functionality as described below. The projects may be stored locally or downloaded or otherwise accessed at the time of installation. 
     The operational information may include dependency relationship information and other resource information. For example, the dependency relationship information may include a list of prerequisites for each project, along with a description of why that dependency exists and how the dependent project is used. The dependency relationship information may further include a list of other projects that use each project, together with a description of why that dependency exists and how the dependent project is used. As will be understood from the description below, such information is used to properly assemble stacks as well as to provide stack explanation information to the user. In addition to dependency relationship information, the operational information may include other resource information such as ports used. 
     The category information allows for sorting and filtering of projects. For example, the categories utilized may include:
         Client   Database   Documentation   Internet   J2EE   Programming   Sample   Security   Server   Source Code Management   Testing   XML
 
In this manner, users can conveniently access desired project information.
       

     The machine state information  504 B may include updated information regarding projects and other resources that are available or unavailable on the user machine  502 . For example, if a particular tool such as a database has previously been installed, this may be stored in the knowledge base  504  and taken into account in addressing dependencies and assembling stacks so as to avoid conflicts that might otherwise occur. Similarly, port usage and other resource issues may be accounted for so as to facilitate integration and proper interoperation of installed projects. 
     The illustrated knowledge base  504  further includes stack information  504 C. Certain information may be indexed to stack combinations rather than to individual projects. For example, information corresponding to project information described above may be stored for common stacks. In addition, certain installation information such as testing parameters may be defined in relation to stack combinations. 
     The knowledge base  504  may store various other kinds of information not shown such as operating environment information. For example, information may be stored to support installation for multiple operating systems and to associate particular uses of projects or stacks with particular operating systems. For example, it may be desired to develop on Windows and deploy on Linux. 
     The engine  506  accesses the knowledge base  504  at run time to obtain all necessary information and executes logic for stack assembly, installation and post-installation support as described in detail below. The user can use the graphical user interface  508  to receive prompts and other information to assist in implementing this functionality and to enter associated information. The printer  510  allows for generating hardcopy documentation. 
     It will be appreciated that the illustrated architecture allows for convenient system implementation and maintenance. In particular, projects or other information can be added or modified simply by updating the knowledge base  504  substantially without updating the engine  506  or other system components. Moreover, the engine  506  allows for rendering of interfaces with a consistent look and feel across operating systems or other implementation variations. 
     III. System Functionality 
     As noted above, a system in accordance with the present invention may provide open source stack functionality related to assembly, installation and post-installation support. 
     A. Assembly 
     Stack assembly generally relates to identifying a number of open source and/or other projects to form a stack for addressing a particular endeavor. In this regard, the system of the present invention can be used to perform a number of functions. For example, information regarding particular projects can be accessed in order to obtain a description of the projects as well as dependency information. In addition, information regarding stacks for common types of endeavors, such as electronic commerce web site design, can be accessed. In this manner, software developers who may have limited knowledge of available open source and other resources may quickly assemble stacks. The system is also fully functional to access machine state information, project information and stack information such that the engine can be used to address dependency relationships and facilitate stack assembly as described below. 
     Referring to  FIG. 6 , a user interface screen  600  that may be utilized in connection with stack assembly is shown. As illustrated, the user interface  600  includes a project identification panel  602 , a project description panel  604 , a prerequisite panel  606  and a used-by panel  608 . Generally, the project identification panel  602  displays a list of supported projects with highlighting, graying and other graphical elements to indicate status and certain dependency information as will be described below. The project description panel  604  includes certain project identification and description information as shown, including recommendations and other assistance for the project highlighted in panel  602 . The prerequisites panel  606  identifies projects that are prerequisites of the identified project and the used-by panel  608  identifies other projects that may use the highlighted project. 
     More specifically, in the panel  602 , primary projects are shown in bold. Dependent projects are shown in normal typeface. Mandatory projects are checked and cannot be changed. When a project is highlighted in the panel  602 , information relating to that project, in this case Tomcat, is provided in panels  604 ,  606  and  608 . In the illustrated example, the title and version of the project is identified at the top of panel  604  together with information in parentheses indicating whether it is, for example, a mandatory project or installed project. A link to the project home URL is then provided followed by a link to view the project license. Also shown are categories associated with the project that can be used for grouping or filtering the projects and an identification of the ports used by the project. Finally, a description of the project is provided including, in some cases, recommendations or tips relating to the project. 
     The used-by panel  608  lists other projects that depend on the highlighted project. Conversely, the prerequisites panel  606  shows other projects that are required in order to install the highlighted project. It will thus be appreciated that the panels  606  and  608  collectively define the dependency relationships for the subject project. 
     This dependency relationship information is derived from the knowledge base and is used by the engine to provide assistance in graphical form related to stack assembly. In this regard, if the user selects a project in panel  602  by checking its associated install box, and that project has a prerequisite that can be fulfilled by two or more other projects, or if there is an unchecked dependency, an indication (e.g., audio or visual) may be provided to prompt the user to resolve such issues. In this regard, the project name turns red in the illustrated implementation and the user is unable to continue with stack assembly until the dependency is resolved. For example, if the project JBoss is selected in panel  602 , the JBoss lettering may turn red to indicate that a prerequisite is required. The user can then consult the prerequisites panel  606  which, in this case, would indicate that JBoss needs either MySQL or PostgreSQL to continue. In the illustrated implementation, the “Next” button on the GUI is disabled until the dependency issues have been resolved, thus ensuring that the user does not continue until all requirements are met. In other cases, dependencies may be selected automatically. 
     In the noted example, the user may then elect to select MySQL to satisfy the JBoss dependency. Once the selection is made, the JBoss project will no longer be listed in red thereby indicating that the dependency has been satisfied and stack assembly and installation may proceed. As noted above, a project type is listed in parentheses next to the project name and version at the top of panel  604 . The types of projects include mandatory, dependent, primary or already installed. The project type is a link and if clicked will give a description of each of the project types. Similarly, the license identification is a link which, if clicked, presents the full text of the license in panel  604 . The categories associated with each project are also links. If these links are clicked, other projects in the category are listed in the panel  604 . For example, if the category “server” is clicked, the panel  604  is filled with a project description box with an initial description such as
         Tools usually found on servers or developer workstations. Not typically intended for end users.
 
followed by a listing including ANTLR, Apache, Http Server, etc. Projects listed in this description are links which, if selected, provide a more detailed description of the selected project. In this regard, links may be provided throughout the text, for example, when a supported project is listed in the description of another project.
       

     Once a project has been installed, the next time the user runs the system the installed projects are shaded in panel  602  and are no longer selectable. 
     A button (not shown) is also provided in the tool bar to toggle between install and uninstall modes. If this button is selected, for example, to switch from the install mode to the uninstallation mode, a pop-up box will appear warning that selected projects will not be installed and confirming that this is what the user intends. Once this intention is confirmed by the user, the system enters the uninstall mode. In this mode, the projects that are installed are shown in the project list of panel  602 . Again, primary projects are shown in bold and dependent projects are shown in regular typeface. 
     By way of example, in the install mode, the user may select Aspect J, Castor, Eclipse and Eclipse plug-ins for installation. It may be noted in this regard that if the Eclipse plug-in is first selected, the Eclipse project will be automatically selected. Once all of the desired projects have been selected, the user may select the next button  610  to proceed. If any of the selected projects require more information to be properly installed, a project properties page will be shown to collect this information. A further user interface screen may be provided, if desired, between the noted project selection and project properties screens to check the ports (and potentially other resource requirements) to make sure the machine state is compatible with the selected projects. If the selected project requirements are not met, the user will be instructed as to how to correct them. In some cases, any problems in this regard can be corrected automatically. In any case, installation can be deterred until all requirements have been met, thereby avoiding potential installation complications. The user can choose to go backward and change project selections as one way to resolve any issues. 
     An example is shown in  FIG. 7 . In this case, the user is prompted to enter and re-enter passwords for JBoss and MySQL in the project properties panel  702 . A description of the selected properties is given in panel  704  to assist the user in entering the correct information. Once all necessary installation information has been entered, an installation instruction screen  800  as shown in  FIG. 8  is displayed. This screen provides information to alleviate common issues that may interfere with the installation. Links may be provided in this screen  800  to obtain any additional instructions and requirements that may be useful. 
     When the user is finished with the installation instruction screen  800 , the user can select the next button  802  to go to the installation screen  900  as shown in  FIG. 9 . From the screen  900  the user can select the start installation button  902  to initiate installation. The progress of the installation can be monitored in Window  904 . A pop-up window indicates when the installation has been successfully completed and provides information regarding post-installation instructions. As shown in  FIG. 10 , upon completion of installation, the user is able to select a reports button  1000  to generate installation reports or select the finish button  1002  to complete the installation process. An example of an installation report is shown is shown in  FIG. 11 . Specifically, the report  1100  shows the status of all projects that have been installed at the time of the report. 
     The projects that may be installed in this manner may include, for example: 
     
       
         
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Ant 
               
               
                   
                 ANTLR 
               
               
                   
                 Apache Server 
               
               
                   
                 AspectJ 
               
               
                   
                 AspectJ sample application 
               
               
                   
                 Avalon Phoenix 
               
               
                   
                 BCEL 
               
               
                   
                 BeanShell 
               
               
                   
                 BSF 
               
               
                   
                 Cactus 
               
               
                   
                 Castor 
               
               
                   
                 Castor sample application 
               
               
                   
                 CeWolf 
               
               
                   
                 cglib 
               
               
                   
                 CheckStyle 
               
               
                   
                 Commons 
               
               
                   
                 CVS 
               
               
                   
                 CVSGraph 
               
               
                   
                 CWM 
               
               
                   
                 DB2 
               
               
                   
                 DbUnit 
               
               
                   
                 Display Tag 
               
               
                   
                 DocBook 
               
               
                   
                 DocBook-XSL 
               
               
                   
                 dom4j 
               
               
                   
                 Eclipse 
               
               
                   
                 Eclipse Plugin: AspectJ Development Tools 
               
               
                   
                 Eclipse Plugin: CDT 
               
               
                   
                 Eclipse Plugin: CSS Editor 
               
               
                   
                 Eclipse Plugin: JBoss-IDE 
               
               
                   
                 EJB Benchmark 
               
               
                   
                 Enscript 
               
               
                   
                 blueglue Existing Server Compatibility 
               
               
                   
                 External MySQL Integration 
               
               
                   
                 External PostgreSQL 
               
               
                   
                 FOP 
               
               
                   
                 Fulcrum 
               
               
                   
                 Graphvis 
               
               
                   
                 Hibernate 
               
               
                   
                 Hibernate/AspectJ sample application 
               
               
                   
                 Hibernate/JBoss/AspectJ sample application 
               
               
                   
                 Hibernate/Middlegen sample application 
               
               
                   
                 Hibernate/XDoclet sample application 
               
               
                   
                 HSQLDB 
               
               
                   
                 HttpUnit 
               
               
                   
                 JAF 
               
               
                   
                 JAI 
               
               
                   
                 James 
               
               
                   
                 JavaGroups 
               
               
                   
                 JavaHelp 
               
               
                   
                 JavaMail 
               
               
                   
                 Javassist 
               
               
                   
                 Java Service Wrapper 
               
               
                   
                 Jaxen 
               
               
                   
                 JBoss 
               
               
                   
                 JCS 
               
               
                   
                 JDepend 
               
               
                   
                 JDK 
               
               
                   
                 JDOM 
               
               
                   
                 jEdit 
               
               
                   
                 Jelly 
               
               
                   
                 Jetspeed 
               
               
                   
                 JFreeChart 
               
               
                   
                 JMeter 
               
               
                   
                 JSTL 
               
               
                   
                 JUnit 
               
               
                   
                 jWebUnit 
               
               
                   
                 Log4j 
               
               
                   
                 Lucene 
               
               
                   
                 Maven 
               
               
                   
                 Maven Developer sample application 
               
               
                   
                 Maven Multi-Project sample application 
               
               
                   
                 Maven Server sample application 
               
               
                   
                 Middlegen 
               
               
                   
                 Middlegen/XDoclet/Jbox/Struts sample application 
               
               
                   
                 MinGW 
               
               
                   
                 MSYS 
               
               
                   
                 mod_jk2 
               
               
                   
                 MyFaces 
               
               
                   
                 MySQL 
               
               
                   
                 MySQL Connector/J 
               
               
                   
                 NetBeans 
               
               
                   
                 OpenSSH 
               
               
                   
                 Oracle 
               
               
                   
                 Oro 
               
               
                   
                 PHP 
               
               
                   
                 phpBB 
               
               
                   
                 phpMyAdmin 
               
               
                   
                 PostgreSQL 
               
               
                   
                 PuTTY 
               
               
                   
                 Python 
               
               
                   
                 PyXML 
               
               
                   
                 rdf2dot.xsl 
               
               
                   
                 Regexp 
               
               
                   
                 Roller Weblogger 
               
               
                   
                 Saxon 
               
               
                   
                 Scarab 
               
               
                   
                 SiteMesh 
               
               
                   
                 Spring 
               
               
                   
                 blueglue Sample: Spring-JSF 
               
               
                   
                 blueglue Sample: Spring-Struts 
               
               
                   
                 blueglue Sample: Spring-Tapestry 
               
               
                   
                 blueglue Sample: Spring-Web Work 
               
               
                   
                 blueglue Sample: SpringMVC 
               
               
                   
                 Squirrel SQL Viewer 
               
               
                   
                 Struts 
               
               
                   
                 StrutsTestCase 
               
               
                   
                 SuSE 
               
               
                   
                 Tiles 
               
               
                   
                 Tapestry 
               
               
                   
                 Tomcat 
               
               
                   
                 Torque 
               
               
                   
                 Turbine 
               
               
                   
                 Velocity 
               
               
                   
                 Very Quick Wiki 
               
               
                   
                 ViewCVS 
               
               
                   
                 WebWork 
               
               
                   
                 WinCVS 
               
               
                   
                 XalanX-Diff 
               
               
                   
                 X-Diff 
               
               
                   
                 XDoclet 
               
               
                   
                 Xerces 
               
               
                   
                   
               
             
          
         
       
     
     It is noted that this exemplary listing includes open source projects as well as at least one proprietary application. Other open source projects and proprietary applications may, of course, be supported. 
     The GUI may also execute a filter function to selectively enable or inhibit access to particular projects by individual users, e.g., within a client entity. For example, a company may configure the system to assist in implementing a policy regarding, for example, what projects may be accessed, how such projects may be used, and by whom. In this regard, a company may define such projects on a project-by-project basis or by type; may specify a set of projects that may be used internally, the same or a different set of projects that may be incorporated into products (generally or on a product-by-product basis), and other project sets for other purposes; and/or may specify what projects may be accessed by an individual or a set or sets of individuals e.g., by software developers, by IT personnel, by accounting, etc. 
     It will be appreciated that the filter, the underlying policies and the associated filter parameters are selected by and are the responsibility of the client entity. The filter provides a convenient tool for implementing and improving internal enforcement of such policies after the policies have been devised by the client entity with such consideration of the legal environment and other factors as deemed appropriate by the client entity. It is not intended that the filter be used as a substitute for full consideration of such issues or in lieu a full internal education and enforcement regime. 
     As noted above, a variety of parameters may be used to configure the filter. One such parameter is license type. In the context of open source projects, there are currently over 45 different recognized open source licenses. These include, for example, the General Public License (GPL), Lesser General Public License (LGPL), BSD, and Apache licenses. Open source licenses are not free of restrictions and obligations and different licenses involve different restrictions and obligations in this regard. While these restrictions and obligations are not always unambiguous, and the specific license terms should be consulted with due care, certain characterizations are possible. For example, certain licenses require that the source code of software, including proprietary software, distributed with the licensed open source software be made publicly available. Such licenses generally include obligations with respect to copyright notices and attributions with respect to copies of the software. Client entities will therefore generally need to carefully consider such licenses in relation to intended uses as part of a compliance program. 
     These licenses may serve as a parameter of the noted filter. That is, as noted above, license information is associated with each supported project in the illustrated system. These license designations may be selected or deselected by the client entity or system operator, e.g. using a filter graphical user interface, to enable or disable access to projects based on license or license type. Such configuration may be executed for specific users, user groups, intended uses, etc. Upon definition of such a filter or filters, the GUI is operative to inhibit or facilitate access to projects, generally in accordance with the selected filter parameters. 
     The filter is not necessarily limited to binary allow or disallow functionality. For example, three or more filter levels may be defined such as “red”, “yellow” and “green” levels that may correspond levels of license restrictions or obligations. Thus, a particular client entity might decide, in its own discretion and in accordance with its own internal policy, that GPL licensed projects will be associated with the yellow filter level and BSD and Apache will be associated with the green filter level. 
     The GUI can then be configured to execute different filter functionality in connection with each filter level. For example, “red” projects may be excluded from the project identification panel  602  ( FIG. 6 ) or selection thereof may be disabled. In the case of yellow projects, appropriate warnings regarding use or restrictions on use (e.g., “Internal Use Only” or “please consult with compliance officer prior to use”) may be displayed, or a password or other authorization may be required to complete installation. Green projects may be accessed as described above free from filter inhibitions. It will be appreciated that other filter levels and associated filter functionality is possible in accordance with the present invention. While such automated filtering may be imperfect in matching and executing policy goals and is no substitute for full education and compliance program, it provides a useful mechanism for encouraging adherence to a compliance program which has become a great concern for companies considering use of open source and other projects. 
     It is noted that such filter functionality may have considerable value apart from the illustrated system. For example, the filter may be used by a compliance officer, wholly independent of any stack assembly, installation and support functionality, to screen projects proposed for use by employees. Moreover, such a filter may be implemented in connection with an Internet gateway filter (e.g., otherwise used to limit internet access in accordance with company policy) to inhibit downloading of designated projects, for example, based on associated URLs. Other execution environments and uses of the filter are possible in accordance with the present invention. 
       FIG. 12  is schematic diagram illustrating a filter system  1200  in accordance with the present invention. The illustrated system  1200  includes logic for executing one or more filters  1202 . For example, different filters  1202  may be defined for different users or user groups within a client entity. 
     The filters  1202  may be defined by a user by way of user interface of  1204 . In this regard, filter identification information, filter parameters and the like may be entered by way of a template or a series of menus displayed on the user interface  1204 . In this manner, the user can define a number of filter parameters such as user parameters  1208 , use parameters  1210  and license parameters  1212 . The user parameters  1208  may identify specific users or user groups, e.g., application developers, IT personnel, accounting, etc. The use parameters  1210  define the intended or allowable uses. Thus, for example, it may be desired to allow one set of projects for internal uses and a second (typically more limited) set of projects to be incorporated into products. The license parameters  1212  allow for controlling access or use of projects based on license associations. Thus, as noted above, certain licenses may be associated with a green filter level, others may associated with a yellow filter level and still others may be associated with red filter level. Appropriate filter rules may be defined for each of these filter levels. 
     Based on such filter configuration information, the filters  1202  selectively allow access to or use of projects  1206  by a user system  1214 . For example, the filters  1202  may inhibit access to selective ones of the projects  1206 , may prevent installation of selected ones of the projects  1206 , or may provide certain warnings or require certain authorizations in connection with access to or use of individual ones of the projects  1206 . Such filtering functionality may be executed in response to an identification of the user system  1214 , a user I.D. entered via user system  1214  or otherwise, or an intended use entered by the user. The projects  1206  may be defined by a list of supported projects of a stack assembly, installation and support system as described above, a listing of projects defined by a compliance policy of a client entity, or projects that are identified on a case by case basis, for example, in connection with a request to download a project via the internet. 
       FIG. 13  is a flow chart illustrating a process  1300  for configuring and operating a project filter in accordance with the present invention. The illustrated process  1300  is initiated by accessing ( 1302 ) a filter configuration utility. Such configuration may be implemented by a client entity, a system provider, or other operator. Using the utility, a filter is selected ( 1304 ). This may involve associating a filter identification with a particular filter to be configured. In this regard, it will be noted that a client entity, a system provider or other operator may define and manage multiple licenses. 
     Once the filter is selected, filter levels may be defined ( 1306 ) for that filter. As noted above, a filter may be a binary in this regard or may include more than two filter levels. Thus, a binary filter may be operative to selectively allow or disallow access to specific projects by specific users for specific purposes. A filter with more than two filter levels may allow access, disallow access or allow access with certain restrictions or authorizations. Individual users or user groups may then be selected ( 1308 ) for association with the defined license. This allows for different levels of access to particular projects or project groups (e.g., defined by an associated license type) on an individual user basis or by a user group such as an applications development group. 
     The illustrated process  1300  involves associating ( 1310 ) projects with the defined filter levels. Again, this may be done on a project-by-project basis or by groups of projects, e.g., as grouped based on license type or another category such as noted above. It will be appreciated that other filter parameters may be defined in this regard such as, for example, expiration dates and copying or distribution parameters. Once all desired filter parameters have been defined, it is determined whether additional filters need to be defined ( 1314 ). If additional filters are to be defined, this process is repeated. Otherwise, the filter is activated ( 1316 ) for use in the desired project filter environment. 
     In use, the filter is operated to identify ( 1318 ) a user for a given filter function. The user may be identified based on user identification information entered by the user or based on the identity of the user machine or system. An intended use may also be identified ( 1320 ). The intended use may be entered by the user or may be inferred from a user group or other information. In this regard, it will be appreciated that the filter may be operative to a prompt user to enter such information as a gateway function prior to accessing a stack assembly, installation, de-installation and/or support functions. In addition, the subject project is identified ( 1322 ). Depending on the specific implementation, such identification may be responsive to a request, such as an installation request, entered by the user or may be performed independent of any user input, in the background or prior to running of the stack assembly, installation and/or support function. In this regard, the filter may operate to prevent display of a filtered project or to prevent selection of a filtered project independent of any input by user. Finally, the filter is operative to execute ( 1324 ) the filter function. Such execution may involve selectively allowing access to an identified set of projects, selectively disallowing access to or particular uses of an identified set of projects, or display of limitation information/require appropriate authorizations. 
     An exemplary installation process  1500  is shown in  FIG. 15 . The illustrated process is initiated by receiving ( 1502 ) input information for a stack assembly. It will be appreciated that the process may be initiated in a variety of ways. For example, some users may know that they are interested in assembling a package that includes a particular project that is relevant to a given endeavor. In this case, such users may simply identify that project, for example, by scrolling through a list of supported projects or by using a search function, and then work through dependency relationships as discussed above. In other cases, users may know the name of a proprietary application and may be interested in identifying an open source analog. In such cases, a tool may be provided for identifying such association. In still other cases, a user may not know the name of a project but may only know the function of interest. In these cases, assistance may be provided in the form of graphical user interfaces to assist the user in initiating the installation process. For example, menus may be provided, such as pull-down menus, whereby the user can identify a function of interest. Additionally or alternatively, supported projects may be graphically illustrated, for example, with links to project descriptive information, to assist a user in identifying a project of interest. As a further alternative, the process may be initiated with an interview process over a number of interfaces to identify user needs. It will be appreciated that a wide variety of interface mechanisms are possible in this regard. 
     In any event, once input information is thereby received, the illustrated process  1500  involves providing ( 1504 ) options for at least one project. Thus, for example, if the input information indicates that the stack of interest relates to web design, a variety of web design project options may be identified. For example, such identification may be accomplished by highlighting or otherwise drawing attention to such projects in a list of supported projects. Alternatively, the relevant projects may simply be listed with links to user interfaces that provide project information as described above. It will be appreciated that in some cases only one project may be available rather than a selection of options. 
     A selection can then be received ( 1506 ) for a first project of a stack under assembly. For example, one project from the noted listing of options may be selected via a graphical user interface. Upon such selection, the system determines ( 1508 ) dependency relationships for the project. Such dependency relationships may include, for example, projects on which the selected project depends as well as other projects that are used by the selected project. The system also determines ( 1510 ) a machine state. For example, this may involve identifying projects that are already installed on the user&#39;s machine. The project filter may also be applied ( 1512 ) at this point. Based on all this processing, the system constructs ( 1514 ) a display reflecting the project filter, machine state and dependency relationships. Thus, based on the project filter, the set of projects that is available for selection or installation may be limited. Based on machine state, previously installed projects may be identified as installed or may be unavailable for selection to be installed. The dependency relationships may be reflected in various graphical elements and text as described above. 
     From this display, this system can receive ( 1516 ) a project selection. For example, the user may select a project on which the first project depends. After such selection, the system can determine ( 1518 ) whether all dependencies are resolved. If the dependencies are not resolved, the user may be prompted to make further project selections. Otherwise, the system indicates ( 1520 ) that assembly is complete. Such an indication may be provided by way of a pop-up box or other active display element, or may simply be provided by way of the absence of any remaining dependencies (for example, the first project listing may switch from red to black). 
     It should be appreciated that the system of the present invention may be used simply to assemble a stack without actually effecting installation and that is an important aspect of the present invention. For example, a developer may use logic resident on the developer&#39;s system or access a website to execute the functionality described above in order to facilitate the process of, for example, addressing dependency relationship issues and filter functions associated with the client entity&#39;s licensing compliance program. The individual projects of that stack may then be obtained and installed independent of the system of the present invention. However, the installer of the present invention performs a variety of useful functions in connection with installation as will be described below. 
     B. Installation 
     It should be understood that the identification of a set of projects where the dependency relationships are internally satisfied does not mean that installation will be successful and free of problems. It is generally still necessary to resolve conflict issues, integrate projects (e.g., so that a given project is configured to point to the correct database), and to test the installed stack for proper installation and interoperation of the projects. In addition, a particular sequence may be required for installation. In accordance with the present invention, the GUI is operative to execute a variety of functionality in this regard. 
     One such function is performing pre-installation checks. For example, the GUI may identify and resolve port conflicts. As noted above, the project information associated with individual projects identifies the ports that are utilized by that project. This port information can be compared to identify and resolve conflicts. The system may further perform a check to verify that any files or other resources required by a project are available and to otherwise verify that all environmental requirements for a project are satisfied on the user machine or system. 
     Another function is control of the actual installation process. In this regard, the engine may obtain the project list for a stack, analyze the dependency relationships and any other necessary project information to determine a suitable sequence for installation and then execute installation in that sequence. Prior to executing this installation, the controller may execute logic to identify any resources that may be required in order to effect the desired installation. 
     Another function that is executed by the GUI in connection with installation is database integration. In this regard, individual projects may require a particular database and different projects may be associated with different databases. The GUI is operative to integrate the individual projects with the desired databases so that the projects point to the desired database. 
     After installation and database integration have been performed, tests may be performed on the installed stack to verify proper operation of the installed stack. This is accomplished by causing the stack to run on the user machine and then executing test procedures that are defined for particular projects, combinations of projects or overall stacks. For example, such tests may involve looking for particular files, checking ports, pinging a server, etc. It will be appreciated that the particular tests may be determined empirically or based on acquired expertise to provide a high likelihood of identifying common installation errors. 
     The installed stack may then be run with selected samples. That is, a tutorial specifically designed for the installed stack may be provided by the GUI. The user can run this tutorial to learn how to use the installed integrated stack. In connection with this stack, the installed stack executes certain samples. This operates to provide sample tests. That is, proper operation of the stack is verified in connection with executing the samples. These tests are similar to the tests described above but touch more layers of the software stack than the earlier tests and operate in an execution environment. If any errors are identified as a result of these tests, error messages may be provided together with information regarding resolution of the errors or instructions to repeat a portion of the installation process. 
     Similar issues are presented in connection with addressing project updates. In the context of operating stacks composed of projects from independent sources, e.g., multiple third parties or open source developers, it will be appreciated that updates generally will not be coordinated. That is, updates may occur at different times and may or may not have an impact on compatibility. The installation process described above can be implemented not only in connection with an initial installation, but also in connection with an update installation. That is, appropriate checks, installation sequencing, testing and the like can be designed and executed for a given update. 
     In this regard, update installations may be implemented automatically, upon manual retrieval of the update, or the user or an administrator of the client entity may be notified of the availability of an update. For example, a system operator may monitor the availability of updates for supported projects and download appropriate information to users or client entities. A user or client entity may then be advised of the availability of updates upon logging into a network, loading of a stack assembly, installation and support system, or selection of any affected project. Such updates may relate to updated project options and support materials as well as to updated software updates. The user or client entity may then select to install or not install the update. It will be appreciated that not all users/client entities may wish to install all updates in this regard. 
     It will thus be appreciated that the illustrated system provides a number of advantages with regard to the installation and update process and this installation process, considered independent of stack assembly or post-installation support, constitutes an important aspect of the present invention. That is, various elements of this installation process would provide advantages even in the context of a stack assembly developed independent of the present invention. However, even upon assembly and installation of a stack of multiple open source projects, certain post-installation support may be desired. The present invention provides significant advantages in this regard, as will be described below. 
     C. Post-Installation Support 
     Upon assembly and installation of an open source software stack, the stack is ready for use by the end user. However, a variety of post-installation functionality may be useful to allow optimal performance of the stack. The present invention provides a variety of functionality in this regard, as described below. Many users may benefit from a tutorial to educate the end user as to the proper use and capabilities of the installed stack. As noted above, tutorials are available for some open source software projects. However, such tutorials generally are not specifically adapted to provide instructions in the context of particular stacks that may be assembled. The present invention provides tutorials in the context of such stacks. The system described above supports a selected set of open source and other projects. These projects can be combined to define a large but finite set of software stacks. The knowledge base stores tutorial information for many or all of these stacks or subsets thereof. Upon installation of a stack, the associated tutorial or tutorials are made available to be run by the user. 
     Another important post-installation function relates to users manuals or other supporting documentation. As noted above, supporting documentation may be available in connection with individual open source projects. However, heretofore there has generally not been a convenient mechanism to obtain supporting documentation relating to a particular stack. This problem is addressed by the present invention by storing support documentation as structured XML documents. That is, chunks of supporting documentation text are associated with a tag system that links the text to particular projects, combinations of projects and overall stacks. For example, projects and stacks may be related by parent, child and other hierarchical tag structures. When a particular stack is installed, the relevant support documentation can be readily retrieved using the tag system to compile customized support documentation. Associated graphics may be assembled on a custom basis, also. The supporting documentation may be specifically provided for Linux, Windows, and/or other criteria specified by the user or indicated in the user machine information stored in the knowledge base and the appropriate documentation in this regard may be retrieved based on metadata (e.g., tag) associations. 
     It will be appreciated that the ability to provide custom tutorials and supporting documentation for an open source project, a combination of projects or an overall stack is an important advantage of the present invention that may be utilized independent of the stack assembly and installation tools noted above. For example, developers who have executed a custom stack installation independent of the tools noted above may wish to utilize the present invention to obtain supporting tutorials or documentation. For example, this may be accomplished by running logic resident on the developer&#39;s system or by accessing a website operative to provide such tutorials or documentation on a fee basis. 
     The combination of the flexibility of open source software and the ease of assembly and installation provided by the present invention yields a number of advantages that can not be readily realized in connection with proprietary systems or with open source software in the absence of the tools of the present invention. For example, a user may wish to try various stack options to determine which is optimal for a particular endeavor. For example, a user may wish to switch between different available database tools in connection with a particular open source software stack. In accordance with the present invention, a database switcher, or a switcher for other software components, may be provided. In this manner, the user can prompt the system to switch between one database and another. This system is operative as described above to integrate associated projects of a stack so that they point to the newly selected database. The user can then compare performance of the stack with one database tool (or other resource) and another database tool (or other resource). In this manner, optimization of performance for a particular endeavor can be conveniently achieved. It will be appreciated that proprietary systems generally do not accommodate comparison as between tools of competing providers. Open source systems theoretically allow for such comparisons but as a practical matter this cannot be performed due to the significant complexities associated with switching of tools and associated integration. 
     The system described above can be implemented a number of ways. For example, the associated logic may be disseminated in physical form to clients with updates provided periodically. Alternatively, the associated logic may be downloaded from an operator&#39;s website by a client entity and updates may be periodically downloaded in similar fashion. As a still further alternative, the system may be operated as a hosted application. In any event, use of the system may be licensed, for example, on a per user per year basis. In this regard, it may be desired to make information regarding such licenses available to the licensee while protecting the license information against unauthorized modification. 
       FIG. 14  is a schematic diagram illustrating a system  1400  for managing such license information. The illustrated system includes a license manager  1402  for managing information that is available to the user via a user interface  1410 . The system  1400  may be resident on the client equipment of the system provider, or another location, and may be distributed across multiple platforms. The license manager  1402  is operative to receive requests for license information entered via the user interface  1410  and to manage access to license information of  1404 . In this regard, the license information  1404  includes license files  1406  for individual licenses. The license file  1406  includes a public portion  1406   a  and a private portion  1406   b . The information available in the public portion  1406   a  and private portion  1406   b  may overlap to an extent but the private portion  1406 B will generally include additional information. In the illustrated implementation, the public portion includes, for example, a license identification and an expiration date. Such information may be used, for example, to enable the user to identify the license at issue and obtain information of legitimate use to the client entity. 
     The private portion  1406   b  may include additional information, such as information defining the license term, as to which access is to be limited. The private portion of  1406   b  can be accessed by an authorized individual, for example, to update the expiration date or to add licensed seats. This is accomplished by entering license identification information via the user interface  1410  and requesting access to the restricted access fields. In response to such an access request, the user is prompted to enter a password or other security information. This password information is used to encrypt information entered into the private portion of  1406  or to decrypt information from the private portion  1406   b . In this manner, appropriate license information is made available while protecting restricted access information such as information fundamental to enforcement of the license terms. 
     While various embodiments of the present invention have been described in detail, it is apparent that further modifications and adaptations of the invention will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention.