Abstract:
A system, method, and computer readable medium for maintaining mappings between resources inside an isolated environment and outside the isolated environment for one or more applications. The system may include a plurality of lists of resources requested by the one or more applications during installation and while executing, and a corresponding lists of resources inside the isolated environment. The system may also include a list of resource exceptions, wherein the mappings between resources as requested by the applications and their corresponding values in the isolated environment are maintained subject to the list of exceptions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is related to U.S. patent application Ser. No. 12/334,654, filed Dec. 15, 2008, titled METHOD AND SYSTEM FOR PROVIDING STORAGE CHECKPOINTING TO A GROUP OF INDEPENDENT COMPUTER APPLICATIONS, and U.S. patent application Ser. No. 12/334,660, filed Dec. 15, 2008, titled METHOD AND SYSTEM FOR PROVIDING CHECKPOINTING TO WINDOWS APPLICATION GROUPS, the disclosure of each of which is hereby incorporated by reference herein in their entirety. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not Applicable 
     NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION 
     A portion of the material in this patent document is subject to copyright protection under the copyright laws of the United States and of other countries. The owner of the copyright rights has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office publicly available file or records, but otherwise reserves all copyright rights whatsoever. The copyright owner does not hereby waive any of its rights to have this patent document maintained in secrecy, including without limitation its rights pursuant to 37 C.F.R. §1.14. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention pertains generally to enterprise computer systems, computer networks, embedded computer systems, wireless devices such as cell phones, computer systems, and more particularly to methods, systems and procedures (i.e., programming) for providing application isolation for multiple applications running on a host operating system. 
     2. Description of Related Art 
     In many environments one of the most important features is to ensure that one running application doesn&#39;t affect other running applications, and that the crash of one application doesn&#39;t compromise other running applications. In many environments applications share system resources, libraries and hardware, which exposes subtle interconnects between seemingly unrelated applications. 
     Several approaches have been developed addressing this fundamental problem. The first level of application isolation is provided by the operating system. Modern operating systems such as Linux, UNIX, Windows2000, NT, XP and Vista provide some level of application isolation through the use of processes, and the underlying hardware memory management unit. The use of processes generally ensure that one running application process cannot address memory owned and used by other processes. This first level of isolation does not address the use of shared resources, such as files, file systems, shared memory, and libraries, so other approaches have been developed 
     In U.S. Pat. No. 6,496,847 Bugnion et al. teach the use of a virtual machine monitor (VMM) with a protected host operating system (HOS). This invention partially solves the isolation problem by placing every application into its own VMM. The solution requires the use of a VMM subsystem and in some cases a customized operating system. U.S. Pat. No. 6,496,847 does not provide isolation at the level of individual applications, but for entire operating systems with all the applications within it. It does not address the problem of application isolation with multiple natively running applications on one host computer. 
     In U.S. Pat. No. 6,601,081 Provino et al. teach the use of a virtual machine for a plurality of application programs. As with U.S. Pat. No. 6,496,847 the use of a VM subsystem simply moves the problem to a different layer, and does not address the fundamental issue of application isolation with several natively running applications on one host computer. 
     In U.S. Pat. No. 7,028,305 Schaefer teaches a system for creating an application protection layer to separate an application from the host operating system. Shaefer primarily teaches how to intercept the Windows registry to capture configuration information for Windows application and how to create a virtual operating environment for the application. Access to files is provided via a virtual file system, access to registry information via the virtual registry etc. For Unix and MacOS few specific teachings are presented. 
     The present invention provides a system, method, and computer readable medium to create an application isolation environment where applications can run unmodified, on un-modified operating systems without requiring any virtual environments, virtual machines or virtual machine monitors. The present invention also teaches how to manage and handle applications that share libraries and resources, and how to handle complex multi-process applications. In one embodiment an implementation in the Linux environment is described, in another embodiment an implementation on Windows is described. 
     BRIEF SUMMARY OF THE INVENTION 
     A method, system, apparatus and/or computer program are described for achieving application isolation for single and multi-process applications and their associated resources. The application isolation is provided without requiring any changes to the host operating system kernel or requiring any changes to the applications. The application isolation is fully transparent to both operating system and application and automatically adjusts for resources such as memory, storage, and CPUs being allocated and released. The application isolation is provided in an interception layer interposed between the individual applications and the operating system and an interception database. Preferably, any functional changes to system calls are done exclusively within the interception layer and interception database, and only in the context of the calling application. 
     Another aspect of the present invention relates to a method and a computer readable medium comprising instructions for application and application group isolation. The instructions are for installing the applications into the isolated environment, running the application in the isolated environment, un-installing applications from the isolated environment, configuring the isolated environments, and deploying the isolated environments. 
     Yet another aspect of the invention relates to a system for maintaining mappings between resources inside an isolated environment and outside the isolated environment for one or more applications. The system comprising: a plurality of lists of resources requested by the one or more applications during installation and while executing; corresponding lists of resources inside the isolated environment; and a list of resource exceptions, wherein the mappings between resources as requested by the applications and their corresponding values in the isolated environment are maintained subject to the list of exceptions. 
     DEFINITIONS 
     The terms “Windows” and “Microsoft Windows” are utilized herein interchangeably to designate any and all versions of the Microsoft Windows operating systems. By example, and not limitation, this includes Windows XP, Windows Server 2003, Windows NT, Windows Vista, Windows Server 2008, Windows Mobile, and Windows Embedded. 
     The terms “Linux” and “UNIX” are utilized herein to designate any and all variants of Linux and UNIX. By example, and not limitation, this includes RedHat Linux, Suse Linux, Ubuntu Linux, HPUX (HP Unix), and Solaris (Sun Unix). 
     The term “node” and “host” are utilized herein to designate one or more processors running a single instance of an operating system. A virtual machine, such as VMWare or XEN VM instance, is also considered a “node”. Using VM technology, it is possible to have multiple nodes on one physical server. 
     The terms “application” is utilized to designate a grouping of one or more processes, where each process can consist of one or more threads. Operating systems generally launch an application by creating the application&#39;s initial process and letting that initial process run/execute. In the following teachings we often identify the application at launch time with that initial process. 
     The term “application group” is utilized to designate a grouping of one or more applications. 
     In the following we use commonly known terms including but not limited to “process” “process ID (PID)”, “thread”, “thread ID (TID)”, “thread local storage (TLS)”, “instruction pointer”, “stack”, “kernel”, “kernel module”, “loadable kernel module”, “heap”, “stack”, “files”, “disk”, “CPU”, “CPU registers”, “storage”, “memory”, “memory segments”, “address space”, “semaphore”, “loader”, “system loader”, “system path”, and “signal”. These terms are well known in the art and thus will not be described in detail herein. 
     The term “transport” is utilized to designate the connection, mechanism and/or protocols used for communicating across the distributed application. Examples of transport include TCP/IP, Message Passing Interface (MPI), Myrinet, Fibre Channel, ATM, shared memory, DMA, RDMA, system buses, and custom backplanes. In the following, the term “transport driver” is utilized to designate the implementation of the transport. By way of example, the transport driver for TCP/IP would be the local TCP/IP stack running on the host. 
     The term “interception” is used to designate the mechanism by which an application re-directs a system call or library call to a new implementation. On Linux and other UNIX variants interception is generally achieved by a combination of LD_PRELOAD, wrapper functions, identically named functions resolved earlier in the load process, and changes to the kernel sys_call_table. On Windows, interception can be achieved by modifying a process&#39; Import Address Table and creating Trampoline functions, as documented by “Detours: Binary Interception of Win32 Functions” by Galen Hunt and Doug Brubacher, Microsoft Research July 1999”. Throughout the rest of this document we use the term to designate the functionality across all operating systems. 
     The term “file context” or “context” is used in relation with file operations to designate all relevant file information. By way of example, and not limitation, this includes file name, directory, read/write/append/execute attributes, buffers and other relevant data as required by the operating system. 
     The term “transparent” is used herein to designate that no modification to the application is required. In other words, the present invention works directly on the application binary without needing any application customization, source code modifications, recompilation, re-linking, special installation, custom agents, or other extensions. 
     The terms “private and isolated environment” and “isolated environment” are used herein interchangeably to designate the private area set aside for application isolation, as described in further detail below. 
     The present invention provides application isolation at several levels: 1) during installation, all installation and registration information is intercepted and installation is re-directed to a private and isolated environment, 2) during launch of an application the installation information is retrieved and provided to the application again via interception, and 3) during access to external resources interception of all access is re-directed as necessary. The combination of all levels of isolation provides for fully transparent application isolation. Thus at all times, access to resources, configuration and run-time information is intercepted and redirected. 
     By way of example, and not limitation, for embodiments within Windows operating systems, access to the Windows Registry is intercepted and included in the application isolation. 
     Further aspects of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
       The invention will be more fully understood by reference to the following drawings which are for illustrative purposes only: 
         FIG. 1  is a block diagram of the core system architecture showing two applications, the interception layer, and the interception database. 
         FIG. 2  is a block diagram illustrating installation and running of applications 
         FIG. 3  is a block diagram illustrating un-installation 
         FIG. 4  is a block diagram illustrating the Interception Database 
         FIG. 5  is a block diagram illustrating running application groups 
         FIG. 6  is a block diagram illustrating running multiple application groups concurrently 
         FIG. 7 . is a block diagram illustrating installation-free deployment 
         FIG. 8 . is a block diagram illustrating administration 
         FIG. 9  is a block diagram illustrating various deployment scenarios 
         FIG. 10  is a block diagram illustrating interception data and control flow 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring more specifically to the drawings, for illustrative purposes the present invention will be described in relation to  FIG. 1  through  FIG. 10 . It will be appreciated that the system and apparatus of the invention may vary as to configuration and as to details of the constituent components, and that the method may vary as to the specific steps and sequence, without departing from the basic concepts as disclosed herein. 
     1. Introduction 
     The context in which this invention is described is one or more applications being installed, running and accessing local and remote resources. Without affecting the general case of multiple applications, the following scenarios often depict and describe one or two applications as applicable. Multiple applications are handled in a similar manner. 
     1. Overview 
       FIG. 1  illustrates by way of example embodiment  10  the overall structure of the present invention. The following brief overview illustrates the high-level relationship between the various components; further details on the inner workings and interdependencies are provided in the following sections.  FIG. 1 . Illustrates by way of example embodiment  10  two applications A  22  and B  26  loaded in memory  14  on a node  12 . The interception layers  16 ,  17 , are interposed between the applications  22 ,  26  and the system libraries  18  and operating system  20 . The interception database  28  provides system-wide persistent interception information and configuration information for the isolated environments. The interception layers  16 ,  17  combined with the Interception database  28  provides application isolation  24 . System resources, such as CPUs  36 , I/O devices  34 , Network interfaces  32  and storage  30  are accessed using the operating system. Devices accessing remote resources use some form of transport network  38 . By way of example, system networking  32  may use TCP/IP over Ethernet transport, Storage  32  may use Fibre Channel or Ethernet transport, and I/O may use USB. The present invention access and arbitrate resources through the operating system and does not work at the transport level. 
     2. Installing and Running applications 
       FIG. 2  illustrates by way of example embodiment  40  installation of a typical application “AppXYZ”  42 . The Interception Layer (IL)  50  intercepts all calls to system libraries and the operating system. IL  50  communicates with the Interception Database (IDB)  58  to create a private and isolated environment where the application can execute without depending on or affecting other parts of the environment. By way of example, and not limitation, first the installation process requests a resource  44 , such as opening a file. The resource request is intercepted by IL  50  and a request to create  54  a private instance of the resource is made to the Interception Database (IDB)  58 . The IDB  58  is a system wide database containing mappings  60 ,  62 ,  64  between the resources as the application  42  requests them  60 , and their private values inside the isolated environment  62 , subject to global exceptions  64 . Further details on the IDB are given in section  4  below. By way of example, and not limitation, if the resource request  44  was to create a file in C:\Program Files\AppDir, the IDB may map that to a private location  62 , such as D:\private\AppXYZ\C\Program Files\AppDir. So while AppXYZ  42  operates under the assumption that it&#39;s working on C:\Program Files\AppDir, in reality all access has been intercepted and re-directed to a private and isolated environment in D:\private\AppXYZ\C\Program Files\AppDir. The IDB  58  returns  54  the private resource to IL  50 , which returns the resource handle  46  to the application  42 . As the application  42  uses the resource  46  it operates under the assumption that the original resource request was satisfied, and is unaware that all resources have been relocated to a private and isolated environment. When use of the resource is terminated  48 , the IL  50  sends a message to the IDB  58  that the resource currently is inactive  56 . All mappings are maintained in the IDB  58  after the installation finishes as they may be needed after the initial request. 
       FIG. 2  also illustrates, by way of example embodiment  40 , how an application  42  runs after being installed. As resources are opened, used, and freed, the same steps as described above are used. As the application  42  executes, it generally access or create resources not used during installation. By way of example, if AppXYZ  42  is a word processor, the user may create a document and save it to storage. That document did not exist as part of the installation process, but is handled using the same mechanisms previously taught. As the user choose to create a new document, AppXYZ  42  makes a request  44  to have the file created. This is intercepted by the IL  50  and forwarded  52  to the IDB  58 . The IDB creates a mapping between the Applications  42 s public document name  60 , and the private and isolated document name  62 . As with Application  42  information stored in the IDB  58 , so is the application data information stored persistently until un-installation. 
     At times it may be desirable to store some user-data outside the isolated environment, such as on a central file server. In a preferred embodiment, this is supported by specifying which resource locations should remain fixed and public in the global exceptions  64 . Such public resources are not translated into the isolated environment. 
     3. Uninstalling Applications 
       FIG. 3  illustrates by way of example embodiment  80 , un-installation of a typical application AppXYZ  82 . The un-installation uses and requests resources  84 , which are intercepted by the IL  86  and redirected  88  by the IDB  90 , as described above. All actions, such as deletion of files, are re-directed to the private and isolated location. When the un-install terminates, sometimes called exit( ), the exit is intercepted  92  by the IL  86 , and forwarded  94  to the IDB  90 . The IDB  90  removes all entries mapping  100  application AppXYZ  82  resources  96  against its isolated environment  98 . The application is now uninstalled, and all isolation information has been removed. 
     4. Interception Database and Resource Mapping 
     The Interception Database (IDB) is a system wide database containing mappings between the resources as the application requests them, and their private values inside the isolated environment.  FIG. 4  illustrates, by way of example embodiment  120 , the Interception Database (IDB)  122 , and its various components. The IBD  122  contains two main components, a rules engine  130  and the core resource mappings  132 . The rules engine  130  contains the main high-level configuration information  124  as provided by an administrator  126 . The rules engine  130  and its configuration information  124  includes, but is not limited to, information designating the base directory for installing the isolated environment, specific exceptions  138  to the resource mappings and the general mechanism used to create the mappings. The administrator  126  defines exceptions  138  as needed. The global exceptions contain all resources that should not be remapped to the isolated environments. Examples include, but are not limited to, shared storage, shared devices, network resources, and system-wide resources. 
     The resource mapping  132  maintains mapping between public resources  134  and the corresponding private and isolated resources  136 . The resource mapping  132  also consults the global exceptions  138  prior to translating any public to private or private to public resource requests. 
     Resources take many forms including but not limited to files, fonts, shared libraries, shared devices, and storage. On Microsoft Windows the Registry is an important component and contains system wide configuration information used by most applications. Some resources, such as data files, tend to be local to the individual applications, while e.g. fonts tend to be shared between multiple applications. 
     Access to files are handled by the IL ( FIG. 2-50 ) intercepting all file operations between the application and the system libraries and operating systems. Examples include, but are not limited to open( ), fopen( ), write( ), read( ), close( ), seek( ), remove( ) and the Windows equivalents. Generally these functions either contain a public file name as part of the arguments, or a file handle to an already established file. The files names are remapped as described above, to an isolated environment, and any further reference to the handle is automatically re-directed to the isolated environment. File operations that return information, are translate back to the public values. By way of example, and not limitation, if the applications ask for “current directory”, the public name, as the application expects is returned, and not the private name within the isolated environment. By way of further example, if the current directory is located on shared storage included the global exceptions  138 , the directory is returned un-translated, as it&#39;s subject to the exception handling. 
     File, paths and other resource names can be specified both as absolute values or relative values. By way of example, and not limitation, an absolute path for a document file may be “C:\MyDocuments\myfile.doc”, while a relative reference may be “ . . . \docs\myfile.doc”. Absolute references are resolved as previously described by consulting the public resources  134 , private resources  136  and global exceptions  138 . Relative addresses are resolved in a multi-step process: First relative names are converted to absolute names and then the absolute name is converted as previously described. This mechanism ensures fully transparent support of both absolute and relative naming of all resources. 
     Fonts pose particular problems, as fonts reside both in application-specific directories and global system directories, such as “C:\Windows\Fonts” on Windows and “/usr/X11R6/lib/X11/fonts/” and “/usr/share/fonts/” on Linux. An application may install font both into one or more global font directories as well as application-specific directories. All shared-fonts directories are included in the Global Exceptions  138  as they should be accessed directly. If during installation additional fonts are installed, they are installed according to the policy chosen by the administrator  126 . Prior to installation, the administrator chooses if application-installed fonts are allowed to be placed in the global fonts directory or if they should be placed in the isolated environment. The rules engine  130  consults this administrative choice and upon receiving a request to enumerate the font directory will include isolated-environment fonts if so configured. If the application installs its fonts into its own file structure, the fonts are treated as normal files and are not subject to the automatic enumeration as the application knows where to look for its application-specific fonts. 
     Modern operating systems share components across multiple applications. Such shared libraries also pose a special case. On Windows Dynamic Link Libraries (DLLs) and on Linux/UNIX shared objects (.so files) are examples of such shared components. On Window shared libraries primarily reside in C:\Windows and C:\Windows\System32, but can sit anywhere. On Linux/Unix the primary locations are ‘/usr/lib’, ‘/usr/X11/lib’ and the entire /usr/lib/ directory structure. The loader of the operating system traverses the system PATH to find any requested shared library, but this can be manually or programmatically changed as part of the load process. The PATH is set using environment variables both on Windows and Linux. In order to intercept loading of shares libraries the present invention loads the application in stead of using the system loader directly. This enables interception of library loading done by the loader. If during installation additional shared libraries are installed, they are installed according to the policy chosen by the administrator  126 . Prior to installation, the administrator chooses if application-installed libraries are allowed to be placed in a global directory or if they should be placed in the private and isolated environment. If the libraries are placed into the private and isolated environment, the load PATH is adjusted to search the private location. 
     As with files, libraries can be loaded with both absolute and relative addresses. The load process handles the resource mapping as described above. In all cases, the loading must follow the same path and address resolution as the system loader provides. 
     If the application installs its shared libraries into its own file structure, the libraries are treated as normal files and are not subject to an adjusted PATH or load-order as the application knows where to look for its application-specific libraries. In the preferred embodiment, if the application installs new shared libraries, they are installed into the isolated environment 
     One of the most significant sources of application incompatibilities, and one of the motivators for the present invention, is shared library conflict. By way of example, and not limitation, if a shared library is loaded on the system, and a new application installs an older version of the library, the older version may overwrite the newer version and render other applications non-functional based on having their shared library replaced by an incompatible older version. This is a common problem on both the Windows and Linux platforms. Using the preferred embodiment described above, the application would install the older library into its isolated environment and therefore not affect other applications. The application would load and use the older library without ever being aware that it was provided from the isolated environment, and other applications running on the system would be unaffected by the installation of the older library. 
     Microsoft Windows uses a special configuration system generally referred to as “the Registry”. The registry contains configuration, installation and un-installation information for applications on the system. When an application installs on a Windows system, it uses the registry to store values such as “home directory”, “recent files”, etc. The preferred embodiment on Windows systems additionally include interception of all registry information, and ensures that installation and runtime information that would normally go into the registry, in stead is stored and maintained in the IDB. During installation of a Windows application all registry information is thus stored in the IDB and not the registry. When an application requests registry information, the information is provided from the IDB, and not the registry. This ensures complete application isolation from the registry. 
     The isolated environment contains all application files and shared resources and their respective mappings. These are all preserved persistently on local or remote storage and can be archived, copied and restored as any other set of files. Specifically, the isolated environment directory structure can be copied to a different node, and used directly to start the application on that node. 
     So far the Interception database has been described as a “database”. Based on the teachings above, it&#39;s readily apparent to anyone skilled in the art, that the only requirement is that updates to the resource tables  134 , 136  and  138  be atomic at the record level. This functionality can be readily implemented in a variety of ways, including using Java&#39;s ConcurrentHashMap( ), the Windows .NET equivalents, or by custom programming the data structures and locking. Furthermore, preferably concurrent access to the Interception Database translations is provided. In an alternate implementation such a custom interception database is used in stead of a full database. 
     5. Interception Data and Control Flow 
       FIG. 10  illustrates by way of example embodiment  240  the data and control flow in more detail. By way of example, and not limitation, consider first an environment with the present invention inactive. An application  242  calls a write( )  243  operation. The write operation is resolved by the operating system loader and directed  244  to the system libraries  248  and operating system  250 , and ultimately writes data to storage  251 . Return value is returned  246  to the caller  243  within the calling application  242 . 
     By way of example, and not limitation, consider an environment with the present invention active. An application  252  calls a write( )  253  operation. As described in above, the write( ) is intercepted  254  by the interception layer  262 . Parameters to the write( ) call are translated by the Interception Database  264  and the rules for the isolated environment  266  and the file context and parameters of the calling write are adjusted to point to the isolated environment. The write call  268  is then forwarded to the system libraries  258  and operating system  260  as were the case with the present invention inactive. The return value  266  from the write is returned to the IL  262  which, using the IDB  264 , maps the result back into the original context and returns the value  256  to the caller  253 . The application  252  issuing the write  253  operating is thus unaware that the write is being intercepted and re-directed to the isolated environment. All translation and isolation is performed outside the application  252 , and before the write operation ever reaches the system libraries  258  or operating system  260 . 
     A specific example, using ANSI C, further illustrates the mechanics of the IL  262  and IDB  264  translations. Consider an example where a file is opened for writing, a small text is written, and the file is closed using the following code 
     
       
         
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 int main(void) 
               
               
                   
                 { 
               
               
                   
                    char const *pStr = “small text”; 
               
               
                   
                    FILE *fp = fopen(“/home/user/newfile.txt”, “w”) 
               
               
                   
                    if (fp != null) 
               
               
                   
                      fwrite(pStr,strlen(pStr),1,fp); 
               
               
                   
                    fclose(fp) 
               
               
                   
                 } 
               
               
                   
                   
               
             
          
         
       
     
     The call to fopen( ) returns a file pointer, which the fwrite( ) operation uses to write data to the file. The call to fopen( ) includes the file name “/home/user/newfile.txt” as the first parameter. The Interception Layer  262  intercepts the call to fopen( ) and changes the actual filename to the corresponding location in the isolated environment before passing  268  the call on to the system library implementation  258 . The following fwrite( ) operation is unaware that the file pointer points to the isolated environment and simply writes the data. Finally, fclose( ) is called to close the file. The file pointer still points to the isolated environment and the close proceeds as a close would without the present invention active. 
     6. Application Groups 
     At times multiple applications share data, libraries and work in combination. By way of example, and not limitation, Microsoft Word may include a Microsoft Excel spreadsheet. In general any number of applications may need to collaborate and share data. So far the approach has been to isolate applications so that, to continue the example, if Word and Excel were installed separately, they would both be isolated and not able to work together. To enable sharing between pre-designated applications, the applications need to be grouped together in an application group and installed inside the same isolated environment.  FIG. 5  illustrates by way of example embodiment  140 , an application group  142  operating within the present invention. The administrator  152  pre-defines the application group  142  and the individual applications within the group: App- 1   143 , App- 2   144  and App-n  146 . The administrator  152  commits the application group to the IDB  150 . The IDB uses the same mechanisms as described above for individual applications, and structures the isolated environment  154  so that the individual applications share resources and file system. By installing the applications together they automatically use the same isolated environment and sharing is fully automatic without requiring any additional information. The interception layer  148  intercepts, as previously described, and requires no special configuration; all application group information is contained within the IDB  150  and the settings for the isolated environment  154 . 
     7. Concurrent Operation of Multiple Application Groups 
       FIG. 6  illustrates by way of example embodiment  160 , concurrent operation of three application groups: application group A  162 , application group B  166  and application group C  170 . Each application group consists of one or more applications. As previously described each application group has a dedicated interception layer: IL  164  for application group A  162 , IL  168  for application group B  166 , and IL  172  for application group C  170 . Each interception layer  164 ,  168 ,  172  provide the interception services as previously described, with each attached to only one application group. As previously disclosed, the Interception Database  174  is global, and is shared between all application groups and interception layers. 
     The administrator  176  commits all administrative settings to the IDB  174 , which is reflected in the database tables for the isolated environment  178 . 
     8. Running Multiple Concurrent Instances of One Application 
     At times it may be desirable to run multiple instances of the same application or application group, but in separate isolated environments. Referring again to  FIG. 6  for illustrative purposes. The administrator  176  defines each instance of the application group using separate application group names. Even though Application Group A  162 , Application Group B  166 , and Application Group C  170  are identical, they have been pre-defined with their own environment, and thus run in separate isolated environments without any further intervention or configuration. 
     9. Installation-Free Deployment 
     One of the major problems with application deployment is the actual installation and the associated risks as described previously. Using the present invention, a pre-created isolated environment can be used in place of performing an actual installation. The isolated environment contains all application files, shared libraries, and installation data and can be moved, copied and run from anywhere the present invention is present. 
       FIG. 7  illustrates by way of example embodiment  180 , how to deploy an isolated environment without needing more than one initial installation  181 . First the administrator  196  installs  184  the application group  182 . As previously taught the interception database  186  creates an isolated environment  188  which contains all application group data, including shared files, data and programs. As taught above, the isolated environment is written to storage and can be copied and run elsewhere. With the isolated environment ensuring isolation from the underlying operating system and applications, an isolated environment can be deployed on a different node by copying the entire isolated environment directory structure to the new node and starting the application. Referring to  FIG. 7 , the administrator  196  copies the isolated environment  188  into the first node  190 , the second node  192  and the third node  194 . 
     In an alternate embodiment, the environment  188  is stored on shared storage, and is accessed directly from the shared storage. In this embodiment, the isolated environment is loaded directly from shared storage, and only local data, such as temporary files, are kept locally. 
     In another embodiment, the environment  188  is saved to storage and shipped to a remote site. The remote site loads the environment and runs the applications directly from within the environment without any installations. In this embodiment the present invention may be used for disaster recovery. 
     10. Administration 
       FIG. 8  illustrates by way of example embodiment  200 , the management infrastructure. The administrator  202  communicates configuration preferences to the Interception database  204  for each isolated environment  206 . The IDB  204  contains, as described above, two separate modules: 1) a rules engine (FIG.  4 — 130 ) and 2) management of the resource mappings (FIG.  4 — 132 ). The rules engine implements the administrator provided resource translations and populates the tables (FIG.  4 — 134 ,  136 ,  138 ). 
     The administrator  202  provides general configuration information applicable to all isolated environments and applications  203 , unless explicitly changed for a particular isolated environment  205 . Examples of administrator-provided global configuration information  203  includes, but is not limited to 
     Default storage location for all isolated environments 
     Default resource exceptions 
     Default application and application group naming 
     Default policy for installing fonts and shared resources into global or isolated environment 
     Each setting can be changed, i.e. replaced, on an application by application basis, and on an application-group by application basis. As determined by the administrator, examples of administrator-provided application-level configuration information  205  include, but is not limited to 
     Storage location for isolated environment 
     Logical name of application or application group 
     Application or application-group specific resource exceptions 
     Policy for installing fonts and shared resources into global or isolated environment 
     The combination of the global configuration information  203  with the rules engine (FIG.  4 — 130 ), makes the configuration and deployment on new isolated environment fully automatic after the initial global configuration has been provided. As described, it may be desirable to change one or more of an application&#39;s isolated environment settings. By way of example, and not limitation, if a particular application needs to locally access certain resources only available on a particular server, that one application&#39;s isolated environment would be located on that particular server, while all other environments were centrally stored. The ability to “mix and match” environments and deployments ensure full flexibility and ability to deploy multiple applications in a heterogeneous environment with all the benefits of the present invention. 
     In another embodiment the administrative functions  202  is done programmatically using an Application Programming Interface (API). 
     11. Deployment Scenarios 
       FIG. 9  illustrates by way of example embodiment  220  a variety of ways the invention can be configured to operate. In one embodiment, the invention is configured to run from a central file server  222 , in another it is configured to run on a pair of application servers  224 ,  226 . In a third embodiment the invention is configured to run on a LAN  228  connected PC  232  together with the application servers  224 ,  226 , and with environments loaded from the central file server  222 . In a fourth embodiment the invention is configured to isolate applications on a cell phone  230 , which is wirelessly connected  238  to the Internet  236 , the application servers  224 , 226  and the file server  222 . A fifth embodiment has an isolated environment on a home-PC  234  connected via the internet  236  to the application servers  224 , 226  and the LAN PC  232 . The invention runs on one or more of the devices, can be distributed across two or more of these elements, and allows for running the invention on any number of the devices ( 222 , 224 , 226 , 230 , 232 , 234 ) at the same time 
     12. Conclusion 
     In the embodiments described herein, an example programming environment was described for which an embodiment of programming according to the invention was taught. It should be appreciated that the present invention can be implemented by one of ordinary skill in the art using different program organizations and structures, different data structures, and of course any desired naming conventions without departing from the teachings herein. In addition, the invention can be ported, or otherwise configured for, use across a wide-range of operating system environments. 
     Although the description above contains many details, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the exemplary embodiments of this invention. Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.”