License management system and method with multiple license servers
Contents
1. 8 44 8 44 B PADDR BIPADOR FIG 5 Lic 38 LIC SERVER a ae 38 LIC SERVER ni 38 LIC SERVER A 38 LIC SERVER 40 ae 38 LIC SERVER 38 U S Patent Apr 25 2006 Sheet 4 of 5 US 7 035 918 1 SERVER 40 42 38 SERVERB 4 LIC SERVER 38 fff 97 APPL APPL X C30 28 B IP ADDR 36 IP ADDR lt 26 38 LIC SERVERC 38 LIC SERVERA LIC SERVER B LIC SERVER B 3 38 SERVER 38 LIC SERVER U S Patent Apr 25 2006 Sheet 5 of 5 US 7 035 918 1 LIC SERVER 40 42 38 Lic SERVERB 40 42 38 LIC 40 42 3 7 4 8 7 ut CHIRI X 28 44 APADDR 4g B IP ADDR AIP ADDR B IP ADDR 6 28 4 ADUR B P ADDR b 36 FIG 11 US 7 035 918 1 1 LICENSE MANAGEMENT SYSTEM AND METHOD WITH MULTIPLE LICENSE SERVERS CROSS REFERENCE TO RELATED APPLICATIONS Embodiments of the present invention claim priority from Provisional Application Ser No 60 152 785 filed Sep 3 1999 and are related to U S utility patent applications entitled License Management System And Method With License Balancing Ser No 09 648 720 filed Aug 25 2000 System And Method For Selecting A Server In A Multiple Server License Management System Ser No 09 648 853 filed Aug 252. US 7 035 918 B1 Page 3 Rainbow Technologies Sentinel License Manager System Administrator s Guide Release 6 0 1998 i to 62 Rainbow Technologies Notice for SentinelLM 6 0 UNIX Customers Mar 6 1998 pp 1 2 Rainbow Technologies SentinelLM License Manager System Release 6 1 Release Notes Jan 15 1999 pp 1 7 Rainbow Technologies Sentinel Engineering Product Release Notes SentinelLM License Management System Version No 6 1 Aug 13 1998 pp 1 7 Rainbow Technologies Notice for SentinelLM 6 1 UNIX Customers Sep 18 1998 pp 1 2 Rainbow Technologies SentinelLM License Manager System Administrator s Guide Release 6 1 1998 pp i 61 Rainbow Technologies SentinelLM License Manager Developer s Integration Guide Release 6 1 1998 pp 1 164 Rainbow Technologies SentinelLM License Manager Evaluation Guide Release 6 1 1998 pp i 23 Rainbow Technologies SentinelLM License Manager Programmer s Reference Manual Release 6 1 1998 pp 1 191 Rainbow Technologies SentinelLM License Manager SentinelLM Developer s Guide Release 6 1 1998 pp 1 127 Rainbow Technologies Notice for SentinelLM UNIX Customers Installing from CD Feb 26 1999 pp 1 2 Rainbow Technologies SentinelLM License Management System Release 6 2 Release Notes Feb 12 1999 pp 1 11 Rainbow Technologies Notice for SentinelLM 6 1
3. 20 25 30 35 40 45 50 55 60 65 8 the first license server 14 to come on line is designated as a leader server The leader server always has a global picture of the current distribution of allocations within every license server 14 in the server pool If none of the license servers 14 were definitively started first the license server 14 having a higher priority as established by a leader priority list will be designated the leader server The leader priority list is stored in the RLF 24 and is read at the time of server startup This is known as a leader election process All other license servers 14 are designated as follower servers The ability to intentionally start up a particular license server 14 and force it to be the leader server is advantageous because it may be desirable for a particular license server 14 on a particular subnet to operate as the leader server due to its physical location speed or efficiency In prior art sys tems the leader server always had the highest IP address and to change leader servers required physically reconnect ing to a different address or reconfiguring the license servers by changing the IP address In embodiments of the present invention however the leader server may be changed sim ply by turning a particular license server 14 on first For purposes of illustration only FIG 5 illustrates an example of the distribution tables 36 for a three server pool consisting
4. 9 Claims 5 Drawing Sheets 14 TUC SERVERA LIC SERVER y LIC SERVER CY 14 REF LM PROGRAM LM PROGRAM LM PROGRAM CLIENT 1 CLIENT 2 PROGRAM 18 12 US 7 035 918 B1 Page 2 U S PATENT DOCUMENTS 4 685 055 A 8 1987 Thomas 4 754 395 A 6 1988 Weisshaar et al 4 780 821 A 10 1988 Crossley 4 791 565 A 12 1988 Dunham et al 4 796 220 A 1 1989 Wolfe 5 138 712 A 8 1992 Corbin 5 146 575 A 9 1992 Nolan Jr 5 204 897 4 1993 Wyman 710 200 5 390 297 A 2 1995 Barber et al 5 579 222 A 11 1996 Bains et al 717 167 5 704 032 12 1997 Badovinatz et al 714 4 5 745 879 A 4 1998 Wyman 5 790 664 A 8 1998 Coley et al 5 862 348 1 1999 Pedersen 5 978 565 11 1999 Ohran et al wee 714 13 6 507 863 1 2003 Novaes 709 201 FOREIGN PATENT DOCUMENTS GB 2346989 KR 2001 108689 OTHER PUBLICATIONS 8 2000 5 2000 International Search Report as Issued in International Application Number PCT US00 24359 Mailing Date Aug 2 2001 PC Week Strength in Numbers vol V3 Jul 1986 p 57 Digital Review Apollo Licenses Concurrent Users on Entire Network vol 4 No 20 Oct 26 1987 p 6 IBM Technical Disclosure Bulletin Software Serial Number vol 26 7B Dec 1983 pp 3918 3919 Chovan J Handling Site
5. and distribution table 36 which includes the current distri bution of allocations 40 However new leader server B does not have the global allocation information maintained by the old leader server A Therefore upon becoming the new leader server license server B must now receive this infor mation from the other license servers As illustrated in FIG 9 because license server A is now down within the distri bution table 36 for new leader server B the allocations in use record for license server A see reference character 42 is set to zero and the allocations available record see reference character 38 is set to 40 When new leader server B sends a heartbeat to follower server C the heartbeat contains information which identifies B as the leader server Follower server C will send an ack in response to the heartbeat from new leader server B and in the process will provide information on the allocations in use record and allocations available record for follower server C Once this information is received within the distribution table 36 for new leader server B the allocations in use record for license server C see reference character 42 is set to one and the allocations available record see reference character 38 is set to 29 In addition the record for available allocations for all servers in the pool see reference character 44 is set to 98 In this manner new leader server B receives a global picture of the status o
6. should the licenser server that previously issued the authorization go down Furthermore with embodiments of the present invention allocations for mul tiple vendors can be managed with a single process running on a single license server Embodiments of the present invention also allow am RLF containing a new hard limit of allocations and a new initial distribution of allocations to be loaded onto one license server and then transferred to other license servers in the server pool What is claimed is 1 A system for managing licenses for protected software on a communication network the system comprising at least one client computer coupled to the communication network for requesting authorizations to use the pro tected software and a pool of license servers coupled to the communication network each license server programmed for managing a distribution of one or more allocations to at least one client computer to use the protected software and for maintaining a record of distribution the pool of license servers including a current leader server programmed for maintaining a record of allocations for license servers in the pool wherein the pool of license servers includes at least one follower server an 5 20 40 45 55 60 14 wherein each follower server is programmed such that it is capable of becoming a new leader server if the current leader server can no longer manage the distri bution of allocations fo
7. 12 United States Patent Redding et al US007035918B1 US 7 035 918 B1 Apr 25 2006 10 Patent No 45 Date of Patent 54 75 73 21 22 60 51 52 58 LICENSE MANAGEMENT SYSTEM AND METHOD WITH MULTIPLE LICENSE SERVERS Inventors Mark E Redding Newport Beach CA US Logan A Badia Fullerton CA US Sandeep Handa New Delhi IN Hemant Sharma Lake Forest CA US Sanjay Chopra New Delhi IN Vikram Duwvoori Salinas CA US Shankar Ramamoorthy Santa Cruz CA US Ajay Tripathy New Delhi IN Assignee Safenet Canada Inc Belcamp MD US Notice Subject to any disclaimer the term of this patent is extended or adjusted under 35 U S C 154 b by 268 days Appl No 09 648 697 Filed Aug 25 2000 Related U S Application Data Provisional application No 60 152 785 filed on Sep 3 1999 Int Cl 17 60 2006 01 US CL 709 223 709 203 709 219 709 225 709 226 709 229 709 217 709 228 709 201 709 204 709 245 370 401 370 352 707 10 713 155 713 156 713 168 713 152 713 153 380 30 705 26 Field of Classification Search 714 6 709 209 203 219 223 225 226 229 217 709 228 201 204 245 705 59 26 370 401 370 245 707 10 713 155 156 168 152 713 153 380 30 See application file for complete search history 56 References Cited U S PATENT DOCUMENTS 4 652 990 A 3 1987 Pailen et al 4 6
8. UNIX Tandem Customers Feb 16 1999 pp 1 2 Rainbow Technologies Notice for SentinelLM 6 1 UNIX Customers Sep 23 1998 pp 1 2 Elan Computer Group Comparing Elan License Manager with other software license managers White Paper Jun 15 1995 pp 1 5 Elan Computer Group Elan License Manager Questions and Answers Aug 1995 G 0002556 0002562 pp 1 6 Elan Computer Group Elan License Manager Technical Overview Jul 1995 G0002546 0002555 pp 1 9 Elan Computer Group Elan License Manager Integrator s Guide for Windows Release 5 0 rev Jan 31 1997 ELAN 002589 002597 pp i viii Elan Computer Group Elan License Manager System Administrator s Guide for Windows Release 5 0 rev Jan 31 1997 ELAN 002598 002602 pp i iv Elan Computer Group Elan License Manager Reference Manual Release 5 0 rev Jan 31 1997 elan 002603 002609 pp i vi Common Licensing API License Service Application Programming Interface API Specification v1 02 Jan 28 1993 RTI 3389 3413 pp i 22 Auto Trol Technology Corp Auto Trol Software Protec tion Installation Guide Apr 4 1986 FF00016 00025 10 pages Elan Computer Group Elan License Manager Technical Overview Nov 13 1997 ELAN 001702 001757 pp 1 9 1 2 i iii 1 44 Highland Software Inc End User Programmers Manual Mar 8 1991 BP 00022 BP 00037 pp 1 3 9 11 19 21
9. the industry for improvements in connec tion with management and coordination of multiple license servers or a pool of license servers in software license management systems for computer networks SUMMARY OF THE DISCLOSURE Therefore it is an advantage of embodiments of the present invention to provide a license management system and method for more efficiently managing licenses on network using a pool of multiple license servers It is a further advantage of embodiments of the present invention to provide a system and method that facilitates communication between multiple license servers so that any license server in the pool may act as a leader server should the leader server go down It is a further advantage of embodiments of the present invention to provide a system and method for managing licenses on a network using multiple license servers that allows a client to locate and receive an authorization from a new license server should the licenser server that previously issued the authorization go down It is a further advantage of embodiments of the present invention to provide a system and method for managing licenses on a network using multiple license servers that allows allocations for multiple vendors to be managed with a single process running on a single license server 0 a 5 40 45 50 55 60 65 4 It is a further advantage of embodiments of the present invention to provide a system and met
10. 1 45 61 62 84 85 Auto Trol Technology Corp FLEXIm Programmers Guide Dec 1994 BP 00098 000137 pp 1 36 1 4 Highland Software Inc FLEXIm License Manager Technical Overview Oct 1991 8 pages Globetrotter Software Inc FLEXlm Programmers Guide for Windows version 5 11 Mar 1997 RTI 5219 5290 pp 1 65 Globetrotter Software Inc FLEXlm End User Manual Version 6 0 Oct 1997 RTI5129 5217 pp 1 80 Globetrotter Software Inc FLEXIm Reference Manual Version 6 0 Dec 1997 RTI5291 5508 1 206 Globetrotter Software Inc FLEXIm Reference Manual Version 6 1 Jan 21 1999 RTI5509 5942 cited by examiner U S Patent Apr 25 2006 Sheet 1 of 5 US 7 035 918 1 A LIC SERVERA LIC SERVER BY 14 LIC SERVER 2 LM PROGRAM LM PROGRAM LM PROGRAM CLIENT N CLIENT 4 PROGRAM CLIENT PROGRAM PROGRAM REDUNDANT LICENSE FILE LICENSE CODE A LICENSE CODE B LICENSE CODE FIG 2 LICENSE COE NTRTNT FIG 3 U S Patent Apr 25 2006 Sheet 2 of 5 US 7 035 918 1 APPL v1 0 40 JA IP ADDR B30 B IP ADDR 30 1C IP ADDR APPL v1 0 100 40 1A IP ADDR B 30 B IP ADOR 30 IP ADDR 28 LICENSE TABLE OISTRBUTION TABLE FREE POOL FPA FIG 4 U S Patent Apr 25 2006 Sheet 3 of 5 US 7 035 918 1 LIC SERVER A 38 LIC SERVER B 40 42 38 SERVERC 38
11. 2000 and License Management System And Method For Commuter Licensing Ser No 09 648 502 filed Aug 25 2000 The contents of each of these applications are incorporated by reference herein BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates generally to license man agement systems and processes for managing licenses on a computer network and in preferred embodiments to such systems and processes involving a pool of license servers for managing software licenses among one or more users on the network 2 Description of Related Art The increasing popularity of computer usage in homes and businesses as well as in governmental research and education institutions has brought about a world wide demand for greater software variety and sophistication Indeed the software development industry in most indus trialized countries has shown substantial growth in recent years and is expected to show continued growth through the next decade However as software sophistication increases develop ment costs associated with such software also tend to increase Modern software programs can require months or even years of development often involving expensive resources and teams of highly skilled engineers and pro grammers before a product may be readied for sale or license Thus software development companies are often required to make large investments early in the development of their products in t
12. 58 093 A 4 1987 Hellman Continued FOREIGN PATENT DOCUMENTS GB 2316503 2 1998 Continued OTHER PUBLICATIONS Sentinellm License Management System Release 6 1 Release Notes Jan 15 1999 Retrieved Nov 4 2005 from IDS Continued Primary Examiner James A Reagan 74 Attorney Agent or Firm Venable LLP James Burdett Kavita B Lepping 57 A system for managing licenses for protected software on communication network is disclosed The system comprises at least one client computer and a pool of license servers coupled to the communication network The client comput ers request authorizations to use the protected software The pool of license servers are programmed for managing a distribution of allocations to use the protected software Within the pool of license servers is a current leader server programmed for managing the distribution of allocations for the license servers in the pool and at least one follower server programmed for managing the distribution of alloca tions for that particular follower server Each license server stores a status of the allocations for that particular license server and each follower server communicates the status of the allocations for that particular follower server to the current leader server Each follower server is capable of becoming a new leader server if the current leader server can no longer manage the distribution of allocations for the license servers ABSTRACT
13. 7 is a generalized representation of the distribution tables of leader server A and follower servers B and C ina server pool comprising three license servers in the example of FIG 6 after an authorization has been granted by follower server C according to an embodiment of the present inven tion FIG 8 is a generalized representation of the distribution tables of leader server A and follower servers B and C ina US 7 035 918 1 5 server pool comprising three license servers in the example of FIG 7 after an authorization has been granted by leader server A according to an embodiment of the present inven tion FIG 9 is a generalized representation of the distribution tables of license servers A B and C in a server pool comprising three license servers in the example of FIG 8 after old leader server A has gone down and follower server B has been elected as the new leader server according to an embodiment of the present invention FIG 10 is a generalized representation of the distribution tables of license servers A B and C in a server pool comprising three license servers in the example of FIG 9 after a client who formerly received an authorization from old leader server A has now received an authorization from new leader server B according to an embodiment of the present invention FIG 11 is a generalized representation of the distribution tables of license servers A B and C in a server pool comprising three license servers in
14. License Agreements and Public Domain Software Packages What are the Issues ACM SIGUCCS Conference Toledo Ohio Sep 30 Oct 4 1985 pp 175 179 Brown B Microcomputer Software Exhange at Michigan State University ACM SIGUCCS Conference Toledo Ohio Sep 30 Oct 4 1985 pp 185 197 Halaris A Sloan L Networked Microcomputers New Challenges For Computing Center Management SIGUCCS Newletter vol 13 No 4 Winter 1983 pp 20 26 Gerber H Pringle G Instructional Computing and Local Area Networking SIGUCCS Newsletter vol 17 No 2 Summer 1987 pp 8 13 Kreutzer A On Line System For Controlling and Monitoring Software Usage in a Microcomputer Labora tory SIGUCCS Newsletter vol 18 2 Summer 1988 pp 29 32 Allen K Software Lending Library ACM SIGUCCS XII Conference Proceedings Nov 1984 pp 171 172 InfoWorld FST Introduces a Copy Protection Scheme For Nets vol 7 No 7 Nov 25 1985 p 14 Micro Communications Software Protection vol 2 No 5 May 1985 pp 35 37 PC World LAN Licensing Lags vol 3 No 11 Nov 1985 pp 320 324 328 Rifkin A et al RFS Structural Overview USENIX Summer Conference Proceedings Atlanta Ga Jun 9 13 1986 pp 248 259 Gould E The Network File System Implemented on 4 3BSD USENIX Conference Atlanta Ga Jun 9 13 1986 pp 294 298 Software News The Promise o
15. act that its available allocations count has dropped to 29 to leader server A and the distribution table of leader server A will be updated accordingly Thus as illustrated in FIG 6 the distribution table 36 of leader server A reflects that the allocations available record 38 for follower server B has dropped to 29 the allocations in use record 42 for follower server B has increased to 1 and that the record for allocations available for all servers in the pool see reference character 44 has dropped to 99 20 25 30 35 40 45 50 55 60 65 10 Similarly if another client computer 12 requests authori zation to run Application v1 0 from follower server C follower server C will look at its distribution table 36 determine that it has 30 allocations available and send an authorization back to the client computer 12 As illustrated in FIG 7 once the authorization is sent the allocations available record 38 for follower server C drops to 29 and the allocations in use record 42 for follower server C increases to one This change is then communicated to leader server A whose distribution table 36 will reflect that the allocations available record 38 for follower server C has dropped to 29 the allocations in use record 42 for follower server C has increased to one and that the record for available allocations for all servers in the pool see reference character 44 has dropped to 98 It should be noted in FIG 7 t
16. anage the distri bution of allocations for the license servers wherein the pool of license servers is programmed for communicating with each other and determining when a particular license server can no longer manage a distribution of allocations to use the protected software wherein each client computer that has received an autho rization from a particular license server and the par ticular license server that sent the authorization to the client computer are programmed for communicating heartbeats between each other wherein each client computer that has received an autho rization from a particular license server also receives a leader priority list from that particular license server wherein each client computer that has received an autho rization from a particular license server is programmed for determining whether that particular license server is still capable of managing a distribution of allocations to use the protected software and wherein each client computer that has received an autho rization from a particular license server but has deter mined that particular license server is no longer capable of managing a distribution of allocations to use the protected software is programmed for locating another license server by using the leader priority list and communicating an additional heartbeat to the located license server where the communication of the additional heartbeat conveys the number of allocations of the prot
17. der server will designate that follower server as being down In addition if a follower server does not receive a heartbeat from the leader server within an expected period of time it sends a leader check message to the leader server to check if the leader server is still alive If the leader server is alive it will send an ack in response to the leader check message If no ack is received the follower server will start a leader election process to select a new leader server Selection of a new leader server is described in a related U S utility application entitled System and Method for Selecting a Server in a Multiple License Server License Management System Ser No 09 648 853 filed Aug 25 2000 the contents of which are incorporated by reference herein In communications from leader to follower servers each message contains updated server status up down for each server in the pool When a follower server receives a message from the leader server the follower server updates its server status information which is used when initiating the leader election process It should be understood that follower servers do not ping each other to check if each other is alive because that would generate unnecessary network traffic Thus the follower servers rely on status information passed to them by the leader server In preferred embodiments of the present invention if the leader server sends acknowledgement heartbeats to th
18. ditional heartbeat conveys the number of allocations of the protected software required by the client computer 10 20 25 30 35 40 45 50 55 16 8 A method as recited in claim 7 wherein if the new leader server receives the additional heartbeat from a client computer that has located the new leader server the method further includes the steps of determining if the new leader server had already issued an authorization to the client computer and converting the additional heartbeat to a request for an authorization if the new leader server had not already issued an authorization to the client computer 9 A system for managing licenses for protected software on a communication network the system comprising at least one client computer coupled to the communication network for requesting authorizations to use the pro tected software and a pool of license servers coupled to the communication network each license server programmed for managing a distribution of one or more allocations to at least one client computer to use the protected software the pool of license servers including a current leader server programmed for maintaining a record of allocations for license servers in the pool wherein the pool of license servers includes at least one follower server wherein each follower server is programmed such that it is capable of becoming a new leader server if the current leader server can no longer m
19. e followers and one of the follower servers B for example US 7 035 918 1 receives the acknowledgement but follower server does not only follower server C will send one or more re try heartbeats If follower server C still does not receive an acknowledgement to the re try heartbeats follower server C will communicate with follower server B and attempt to initiate a process to select a new leader server However follower server B has already received an acknowledgement from leader server A so follower server B will communicate with leader server A and inform leader server A that follower server C is initiating a process to select a new leader server At this time leader server A will send a new heartbeat to follower server C If leader server A fails to receive a reply heartbeat from follower server C and follower server C again contacts follower server B about a process to select a new leader then follower server B will communicate to follower server C that a leader server already exists in the server pool At that point follower server C will disassociate itself from the pool Now assume that leader server A goes down Because the license servers 14 are periodically pinging each other the two follower servers B and C will soon determine that leader server A has gone down Further assume that follower server B is then selected as the new leader server New leader server B will already have its own RLF 24 license table 34
20. e available to completely satisfy the request no authorizations are sent and follower server B communicates another message back to the client computer 12 denying the request In preferred embodiments follower server B will then issue a borrow request in an attempt to borrow available allocations from another source Borrowing is described in a related U S utility application entitled License Management System and Method with License Balancing Ser No 09 648 720 filed Aug 25 2000 the contents of which are incorporated by reference herein As noted above in preferred embodiments of the present invention the leader server always has a global picture of the distribution of allocations in the whole server pool Thus any changes to the distribution table of follower server B must be communicated to leader server A In preferred embodiments follower server B can determine the IP address for the leader server A from a leader priority list 46 which is configurable by the network administrator It should be noted that in preferred embodiments the IP address of license servers in the server pool are stored in the leader priority list 46 a data structure separate from the license codes 26 to facilitate faster lookup However in alternative embodiments the IP addresses may be stored in a record associated with the license codes 26 In any case after determining the IP address of the leader server A follower server B communicates the f
21. e license information indicated that a license is available would send a reply to the requesting client computer The shell program or library of API functions associated with the requesting client computer would then respond to the first reply received from a license server having a license file storing license information for the protected software program If the replying license server contains an available license for the protected software program the replying license server provides an authorization message to the requesting client computer If the replying license server does not contain an available license for the protected software program the replying license server provides a message to the requesting client computer indicating that authorization to run the protected software program has not been granted Such a system provides a degree of protection against system failure in the event that one of the license servers crashes or goes down The down server computer would not respond to the poll but other server computers having appropriate license information in their license file would respond to the poll thus allowing the client computer to continue to seek authorization to run the protected software program even though one of the servers was down While the above SENTINELLM systems have operated well in many contexts each license server operates some what independent of other license servers Accordingly there is a need in
22. ected software required by the client computer
23. ed embodiments of the present invention the structure of the distribution tables 36 will be the same for both the leader server A and follower servers B and C but only the distribution table 36 for leader server A the leader distribution table will reflect the allocation status of the other license servers 14 in the server pool In contrast the distribution tables 36 for follower servers B and C the follower distribution tables will only reflect the allocation status of that particular follower server as indicated by the X don t care designations in portions of the follower distribution tables When a user at a client computer 12 desires to run Application v1 0 from a follower server such as follower server B for example the client computer 12 may first load some or all of the protected program into the transient memory of the client computer 12 along with the program code corresponding to a shell or library of API functions Selection of a follower server from which to request autho rization is described in a related U S utility application US 7 035 918 1 9 entitled System and Method for Selecting a Server in a Multiple License Server License Management System Ser No 09 648 853 filed Aug 25 2000 the contents of which are incorporated by reference herein Alternatively the pro tected program may remain in persistent memory 18 until and unless the server computer communicates an authori zation signal to the s
24. ernative embodiments of the present invention the RLF 24 may be updated without the necessity for bringing a license server 14 down In such embodiments the network administrator would initiate a utility from a client computer 12 that sends an update RLF message containing a new RLF 24 to a particular license server 14 The particular license server 14 would then proceed as described above It should be noted that in embodiments of the present invention a network administrator can also use this process US 7 035 918 1 13 to add a license server to the pool by simply bringing the new license server 14 on line When the new license server is brought on line it may have a new RLF 24 In addition to the purposes described above the heart beats communicated between the follower servers and the leader server are also used to enforce majority rule Majority rule is a security measure to prevent excessive authoriza tions from being issued License servers 14 operating under majority rule will only issue an authorization if a majority of license servers 14 in the server pool are up and running Continuing the example server pool described herein for purpose of illustration only suppose the two follower serv ers B and C go down Because of the communication between license servers 14 leader server A will know that only one license server itself is still operating Leader server A will also check a key file which stores the total
25. f LANS MIS Back in Control pp 51 54 56 58 IBM Technical Disclosure Bulletin Device Profile Instal lation Procedure with Validation vol 28 No 4 Sep 1985 p 1487 The DEC Professional PACS Plus Relief for VAX VMS Resource Management Headaches Feb 1986 pp 58 62 64 Software News LAN Applications Prices Are Not Easy to Set Apr 1987 pp 54 56 58 SIGUCCS Newsletter Licensing of Microcomputer Software vol 15 No 4 Winter 1985 pp 9 12 AMC SIGUCCS User Services Conference IX Software Management System Atlanta Ga Oct 11 14 1981 pp 9 17 Brooks C Experiences with Electronic Software Distribu tion USENIX Summer Conference Portland Oregon Jun 11 14 1985 pp 433 436 Leiss E On Authorization Systems with Grantor Controlled Propagation of Privileges CompCon 83 San Francisco CA Feb 28 Mar 3 1983 pp 499 502 Houy T The Challenge of Selling Software on the Internet Electronic Software Distribution White Paper http Awww elan com corp esd htm Nov 4 1997 pp 1 6 IFOR LS and EZ Lok FAQ Product Information http www gradient com support techfaq ifor ezprod htm Nov 7 1997 pp 1 3 Harper Jr R Software Licensing For Installations With Multiple Microcomputers Abstract 86000243 Computers amp Education 1985 vol 9 No 3 1 page Cooper et al Software Protection and Pricing LAN Envir
26. f the license servers in the server pool Meanwhile because client computers 12 connected to a particular license server 14 are also periodically communi cating with each other for example using a regular heart beat function that indicates that each is still functioning client computer A will soon determine that server A went down Client computer A knows that it has received an authorization to run the protected program from server A and therefore knows that it must enter a fail over mode and allocation it will convert the heartbeat to a request and issue an authorization to client computer A If old leader server A should come back up it will be a follower server and have an initial distribution according to the allocations for old leader server A in the distribution table of new leader server B regardless of what is contained in the RLF 24 Old leader server A can become the leader server again if new leader server B goes down When old leader server Acomes back up as follower server A follower server A sends a heartbeat to new leader server B who then 20 25 30 35 40 45 50 55 60 65 12 recognizes that follower server A is back up New leader server B then transmits the current allocation of old leader server A to follower server A Continuing the example of FIG 10 for purposes of illustration only if old leader server A comes back up as follower server A the current allocation of old leader serve
27. hat the distribution tables 36 for follower servers B and C keep track of changes to their own allocations but do not keep track of changes to the allocations of other license servers Continuing the example of FIG 7 for purposes of illus tration only assume that a client computer A has requested and received an authorization to run Application v1 0 from leader server A As illustrated in FIG 8 once the authori zation is sent the allocations available record 38 for leader server A drops to 39 the allocations in use record 42 for leader server A increases to one and that the record for available allocations for all servers in the pool see reference character 44 has dropped to 97 Thus at this point in time one client computer 12 is connected with each license server 14 In embodiments of the present invention the license servers 14 periodically communicate with ping each other so that the license servers 14 know which other license servers 14 are down or up The communication or pinging may be in the form of a periodic signal heartbeat sent from the leader server to the follower servers Server identifica tion information such as the IP address of the follower server may be contained within this heartbeat but license code information need not be communicated If the leader server does not receive an acknowledgement ack from a particular follower server in response to the heartbeat within an expected period of time the lea
28. he hope that the products will provide a volume of sales or license revenues sufficient to cover their development investments and generate profits Illegal software usage and piracy have become a signifi cant problem to software development companies Because of the nature of computer software illegal usage and illegal copying of proprietary software programs can be difficult to detect or deter The increasing usage of computer networks has added to the problem Computer networks can allow multiple users to access and copy software stored by a common network program server or copy and pass software between each other over the network A legitimately pur chased or licensed copy of a software program available on a network could result in many illegitimate usages or copies by unauthorized or unlicensed users having access to the network Various forms of encryption techniques have been devel oped to inhibit usage of encrypted software by unauthorized users that do not possess a decryption program or key However such techniques typically require each authorized users to obtain or be passed a decryption program or key in advance of usage of the encrypted program Accordingly 0 20 25 30 35 40 45 50 55 60 65 2 such techniques can be prohibitively inconvenient for some computer and network environments where it is difficult or impractical to supply each authorized user with a decryption program or key o
29. hell program or library of API functions Loading of the shell program or library of API functions is preferably transparent to the user on the client computer 12 and preferably occurs in response to the user inputting a command to open the protected software for example by clicking a mouse button on an icon associated with the protected software As part of the function of the shell or library of API functions a request is then sent from the client computer 12 to follower server B for one or more authorizations to run the protected program For purposes of this example assume that client computer 12 requested only one authorization Follower server B under the control of the license manage ment software responds to the request by looking at its distribution table 36 to determine whether it has available allocations for Application v1 0 In the example of FIG 5 follower server B has 30 allocations available as repre sented by the allocations available record for each server in the pool reference character 38 in the distribution table 36 for follower server B Because it has available allocations follower server B communicates an authorization message to the client computer 12 As illustrated in FIG 6 once the authorization message is sent the allocations available record 38 for follower server B decreases to 29 and the allocations in use record 42 for follower server B increases to one If an insufficient number of allocations ar
30. hod for managing licenses on a network using multiple license servers that allows a redundant license file containing a new hard limit of allocations and a new initial distribution of allocations to be loaded onto one license server and then copied to other license servers in the server pool These and other advantages are accomplished according to a system for managing licenses for protected software on a communication network The system comprises at least one client computer and a pool of license servers coupled to the communication network The client computers request authorizations to use the protected software The pool of license servers is programmed for managing licenses to use the protected software Within the pool of license servers is a current leader server programmed for managing all license servers in the pool and at least one follower server programmed for managing the distribution of authorizations allocated to that particular follower server Each license server stores a status of the authorizations allocated to that particular license server and each follower server communicates the status of the authorizations allocated to that particular follower server to the current leader server Each follower server is capable of becoming a new leader server if the current leader server can no longer manage the distribution of authorizations for the license servers These and other objects features and advantages of embodiments of
31. iments each license code 26 includes at least one attribute associated with a license policy the number of allocations for using the protected software program and at least one other attribute associated with the identity of the protected software program The number of allocations for using the protected software program is the maximum number of users that can be running the protected software program at any one time and US 7 035 918 1 7 is also referred to as the ceiling or hard limit Data associated with a license policy preferably includes data representing the expiration date or expiration time of the license as granted by the licensee e g the protected software pro gram s owner or developer For purposes of illustration only in the embodiment of FIG 4 only one fictional license code 26 identified as Application v1 0 is stored in the RLF 24 of a license server 14 with a hard limit of 100 total allocations distrib utable across all license servers 14 see reference character 28 In preferred embodiments another attribute of the RLF 24 is the IP address 32 for each license server 26 Another attribute of the RLF 24 is the distribution of the 100 allocations across all the license servers 14 This distribution is identified as the initial distribution 30 and is configurable by the network administrator In the example of FIG 4 an initial distribution 30 of A 40 B 30 C 30 indicates that 40 allocations will
32. include but is not limited to a hard disc drive floppy disc drive tape drive CD ROM or the like having a computer readable medium on which a license management program 22 and a redundant license file RLF 24 are stored An example embodiment of an RLF 24 is shown in FIG 2 as containing license codes 26 for proprietary software programs A B C etc Each license code 26 in one example embodiment comprises a string of data relating to license policy and the software program to which the license policy applies In preferred embodiments license codes 26 for software produced by more than one vendor can reside within the same RLF 24 of the same license server 14 and may be managed with a single process execution of the license management software running on a single license server 14 Thus any given licenser server 14 does not need to have multiple license management processes running to manage licenses for multiple protected vendor applications Instead only one license management program needs to be running on a given license server 14 to manage licenses for protected vendor applications managed by that license server In the example embodiment of FIG 3 a license code 26 comprises a data string defining multiple records or fields R1 R2 RN wherein each record corresponds to an attribute associated with the license policy the software program to which the license policy applies or other infor mation In preferred embod
33. initially be assigned to license server A 30 allocations will initially be assigned to license server B and 30 allocations will initially be assigned to license server C This initial distribution 30 also signifies that the pool will comprise three license servers If the network administrator makes an initial distribution that does not equal the hard limit of allocations see reference character 28 in preferred embodiments of the present invention the extra allocations will be put into a free pool 48 maintained within the distribution table 36 If on the other hand the network administrator makes no initial distribution 30 of allocations in the RLF 24 preferred embodiments will divide the allocations evenly over the number of servers in the pool and any extras will be put in the free pool 48 For example but not illustrated in FIG 4 if initial distribution 30 was assigned by the network administrator information repre senting an even distribution of A 33 B 33 and C 33 would be stored in the initial distribution attribute 30 of the RLF 24 and when a particular license server 14 is started the RLF 24 would load an even distribution of A 33 B 33 and C 33 into the current distribution attribute 40 of distribution table 36 and would load a value of one into the free pool 48 In preferred embodiments of the present invention each RLF 24 stored in each license server 14 is an exact copy of every other RLF 24 of license servers in
34. ity of license servers are managed in accordance with a server pool scheme as controlled by a license management program associated with each license server computer and the shell program or library of API functions associated with each copy of the protected ware program In preferred embodiments the pool of license servers comprises three to 11 servers However it should be noted that alternative embodiments of the present invention are not limited to any particular maximum number of license servers In addition in further alternative embodiments multiple pools of license servers can reside on a single network However for purposes of illustration only embodi ments of the present invention will be described herein with reference to a pool of three license servers An example hardware environment for an embodiment of the present invention is illustrated generally in FIG 1 With reference to FIG 1 a computer network 10 includes a plurality of user or client computers 12 and three license 20 25 30 35 40 45 50 55 60 65 6 servers 14 each coupled for communication over a com munication network link generally referenced at 16 The plurality of client computers 12 are identified as Client 1 Client 2 Client and the plurality of license servers 14 are labeled as Lic Server Lic Server and Lic Server C Embodiments may employ any suitable numbe
35. ives these replies it compares the sequence numbers In the present example follower server A will determine that it has the highest sequence number indicating that follower server A has the latest RLF 24 Follower server A will then send a message to new leader server B indicating that follower server A has the latest RLF 24 New leader server B will then acknowledge this message and goes into a receive mode at which time follower server A copies the RLF 24 to new leader server B Once new leader server B has received a copy of the latest RLF 24 new leader server B notifies other functioning follower servers that it has a new RLF 24 and the new RLF 24 is then copied to the other functioning follower servers In the preferred embodiment described above the leader server is updated with the new RLF 24 before any other license server 14 in the pool because at any point in time the leader server should have the correct and the latest information After the license servers 14 receive the new RLF 24 their license tables 34 and distribution tables 36 are updated based on the new RLF 24 The process described above is advantageous in that it allows a network administrator to update the RLF 24 on each license server 14 without taking each license server 14 off line loading the new RLF 24 and then bringing it back up Instead the RLF 14 for license servers 14 in the server pool can be updated by bringing only one license server 14 down In alt
36. number of license servers 14 in the server pool and note that the key file stores a value of three Although leader server A is still up and running because there is no majority of license servers running only one of the three license servers are running leader server A is precluded by the majority rule from issuing authorizations Without the majority rule which may be ignored in alternative embodiments of the present invention the net work could be intentionally segmented such that each license server 14 becomes isolated from every other license server 14 With the license servers 14 isolated each license server 14 would appear to be the only license server 14 in the server pool and thus would operate as a leader server It would then be possible to receive authorizations from each of these independent leader servers for all allocations for a total of three times as many allocations for each legitimate license Therefore embodiments of the present invention provide an improved system and method for managing licenses on a network using license servers that cooperate with one another and efficiently manage allocations in a network environment The improved system and method facilitates communication between license servers so that any license server may act as a leader server should the leader server go down In addition embodiments of the present invention allow a client to locate and request an authorization from a new license server
37. of license servers A B and C Assume for this illustration that all three license servers have been started up and that license server A has been designated as the leader server and B and C as the follower servers Further assume that the hard limit of allocations for the software program Application v1 0 is 100 as indicated by the hard limit record 28 associated with the license code 26 for Application v1 0 within each distribution table 36 In addi tion assume that the current distribution of allocations is 40 on leader server A 30 on follower server B and 30 on follower server C as indicated in the current distribution record 40 associated with the license code 26 for Application v1 0 within each distribution table 36 Note also that in the embodiment of FIG 5 associated with each license code 26 is a record for available alloca tions for each server in the pool see reference character 38 a record for available allocations for all servers in the pool see reference character 44 and a record for allocations currently in use for each server in the pool see reference character 42 The allocations in these records are values which are incremented or decremented as authorizations are issued returned or borrowed It should be understood that the records identified by reference characters 28 38 40 42 and 44 in FIG 5 are associated with a particular license code 26 but are distinct from it As indicated in FIG 5 in preferr
38. onment Abstract No 86032120 Jurimetrics Journal Winter 1986 vol 26 No 2 1 page Rainbow Technologies Sentinel License Manager Getting Started for Windows TCP IP and Novell NetWare Release 5 0 1997 pp i v 1 24 Rainbow Technologies Notice for SentinelLM 5 0 UNIX Customers 1997 1 page Rainbow Technologies Sentinel License Manager Integrator s Guide for NetWare Release 5 0 1997 pp i vi to IN 10 Rainbow Technologies Sentinel License Manager System Administrator s Guide for NetWare Release 5 0 1997 pp 1 1 to IN3 Rainbow Technologies Sentinel License Manager Reference Manual Release 5 0 1997 pp i 1 to IN12 Rainbow Technologies Sentinel License Manager Integrator s Guide for UNIX Release 5 0 1997 pp i 1 to IN10 Rainbow Technologies Sentinel License Manager System Administrator s Guide for INIX 5 0 1997 pp i 1 to IN4 Rainbow Technologies Sentinel License Manager Integrator s Guide for Windows IP Release 5 0 1997 1 1 to IN12 Rainbow Technologies Sentinel License Manager System Administrator s Guide for Windows TCP IP Release 5 0 1997 pp 1 1 to IN3 Rainbow Technologies Sentinel License Manager Integration Guide Release 6 0 1998 pp i to 130 Rainbow Technologies Sentinel License Manager Programmer s Reference Manual Release 6 0 1998 pp to 187
39. ower server that did not receive the heartbeat starts an election process to elect a new current leader US 7 035 918 1 15 5 A system as recited in claim 1 wherein if a follower server becomes the new leader server then the new leader server sends a heartbeat to each of the remaining follower servers and wherein each of the remaining follower servers commu nicates the status of the allocations for that particular follower server to the new leader server 6 Asystem as recited in claim 1 wherein upon receipt of the record of distribution from each license server the new leader is programmed for amending its record of distribution to include the record of distribution for each license server such that a new record of allocations for the license servers in the pool is created on the new leader 7 A method for managing licenses for protected software on a communication network the method comprising coupling at least one client computer to the communica tion network for enabling the at least one client com puter to issue a request for an authorization to use the protected software over the communication network coupling a pool of license servers to the communication network each license server managing a distribution of allocations to at least one client computer to use the protected software and managing a record of alloca tions selecting one of the license servers in the pool as a current leader server and maintaining a
40. r A see reference characters 42 and 38 in the distribution table 26 of new leader server B which is zero allocations in use 40 available will be communicated to follower server A This allocation is reflected in the distribution table 26 of follower server A in FIG 11 In alternative embodiments of the present invention before bringing old leader server A back up as follower server A the network administrator may use this opportunity to modify the RLF 24 Modification of the RLF 24 may be desirable because a new license code 26 was added or because a modification of the initial distribution of alloca tions 30 for a given license code 26 already in the RLF 24 is desired In preferred embodiments of the present invention each RLF 24 has an associated sequence or version number Each time the RLF 24 is changed the sequence number is incremented Thus if license servers should have RLFs 24 different sequence numbers some RLFs 24 are not up to date Continuing the example above for purposes of illus tration only when old leader server A comes back up as follower server A with a new RLF 24 it sends a server up message which includes the sequence number of its RLF 24 to the other license servers 14 When the other license servers B and C respond to follower server A s server up message license servers B and C will send a reply back to follower server A which includes their own sequence numbers When follower server A rece
41. r of allocations of the protected software required by the client computer 2 Asystem as recited in claim 1 wherein if the new leader server receives the additional heartbeat from a client com puter that has located the new leader server the new leader server is programmed for determining if the new leader server had already issued an authorization to the client computer and converting the additional heartbeat to a request for an authorization if the new leader server had not already issued an authorization to the client computer 3 A system as recited in claim 1 wherein the current leader server is programmed for communicating a heartbeat to each follower server wherein each follower server is programmed for commu nicating an acknowledgment to the current leader server in response to the heartbeat and wherein the current leader server designates a follower server as being down if no acknowledgment is received from that follower server 4 A system as recited in claim 1 wherein the current leader server is programmed for communicating a heartbeat to each follower server wherein if a follower server does not receive the heartbeat from the current leader then the follower server that did not receive the heartbeat sends a check message to the current leader and wherein if the follower server that did not receive the heartbeat does not receive a response from the current leader in reply to the check message then the foll
42. r of client computers 12 and any suitable number of license servers 14 Also while not shown in FIG 1 the network 10 may include additional components including one or more program or file servers routers and or other well known network devices and resources Each client computer 12 preferably includes a suitable processor and associated transient memory such as an RAM for running a protected software program The client computer may be part of a standard personal computer PC network terminal workstation or the like In one preferred embodiment each client computer 12 is coupled to a per sistent program storage memory device 18 which may include but is not limited to a hard disc drive floppy disc drive tape drive CD ROM or the like having a computer readable medium on which the protected software program is stored Also stored as part of the protected software program is additional program code such as code corre sponding to a shell or library of API functions as discussed above for communicating with the license servers which are under control of a license management program in accor dance with communication functions discussed below Each license server 14 preferably includes a suitable processor and associated transient memory such as an RAM for running a license management program as described herein In addition each license server 14 is coupled to one or more persistent program storage memory devices 20 which may
43. r the license servers and wherein upon selecting a new leader server from the pool the new leader server is further programmed for receiving from each license server the record of distri bution for that license server wherein the license servers within the pool are pro grammed for communicating with each other and deter mining when a particular license server can no longer manage a distribution of allocations to use the protected software wherein each client computer that has received an autho rization from a particular license server and the par ticular license server that sent the authorization to the client computer are programmed for communicating heartbeats between each other wherein each client computer that has received an autho rization from a particular license server is programmed for determining based on communication of the heart beats whether that particular license server is still capable of managing a distribution of allocations to use the protected software and wherein each client computer that has received an autho rization from a particular license server but has deter mined that particular license server is no longer capable of managing a distribution of allocations to use the protected software is programmed for locating a new leader server and communicating an additional heartbeat from the client computer to the new leader server where the communication of the additional heartbeat conveys the numbe
44. r to decrypt a program for each user or usage Other software protection techniques have required legiti mate or authorized users to have a special hardware device or circuit installed in or plugged into their computer prior to usage of the protected software See e g U S Pat No 4 446 519 to Thomas Again such techniques can be pro hibitively inconvenient for some computer and network environments For example if the network environment is such that the authorized user must use multiple computers on the network then each computer must be provided with the special hardware device Moreover if the environment is such that computers having the special hardware device are not located in secure facilities then unauthorized users may be able to access the protected software by using the non secure computer in which the special hardware device is installed Accordingly more sophisticated license management software has been developed for managing software licenses for computer networks which do not require encryption of the protected software or special hardware devices in each authorized user s computer For example the assignee of the present invention Rainbow Technologies Inc has mar keted versions of a license management system under the trademark SENTINELLM The SENTINELLM sys tems operate with a license server connected to a network of users The license server stores and manages software licenses for the network use
45. record of allocations for license servers in the pool with the current leader server designating other license servers that are not the current leader server as follower servers selecting one of the follower servers as a new leader server whenever the current leader server can no longer manage the distribution of allocations for the license servers transmitting the record of allocations for each license server to the new leader server determining by communications between the pool of license servers when a particular license server can no longer manage a distribution of allocations to use the protected software communicating heartbeats between client computers that have received an authorization from a particular license server and that particular license server determining for each client computer that has received an authorization from a particular license server if that particular license server is still capable of managing a distribution of allocations to use the protected software wherein for each client computer that has received an authorization from a particular license server but has determined that particular license server is no longer capable of managing a distribution of allocations to use the protected software the method further includes the steps of locating the new leader server and communicating an additional heartbeat from the client computer to the new leader server where the communication of the ad
46. rs in accordance with a license management program stored on the server Each copy of a protected software program on the network is accompanied by a program code corresponding to a shell also known as wrapper or library of Application Program Interface API functions which communicates with the license man agement program on the server When a user starts to run the protected software program the shell code or library of API functions provided with the program communicates a request to use a license to the license server over the network The server under the control of the license man agement software responds to the request to determine whether it is storing an available license for the protected software program If so the server communicates an autho rization message to the user and decrements a count of available licenses stored by the server If not the server communicates another message to the user indicating that no licenses are available In this manner licenses are always stored and managed on a network license server Each network user may have a copy of a protected software program but must communicate with the license server for authorization to use the protected program License management systems which employ a license server as discussed above provide significant advantages with respect to the freedom to readily add delete or change authorized users on the network and the ability to readily control and al
47. ter licensing schemes for example to add or delete licenses or change conditions for licenses by modi fying only the license server files or programs However if all licenses are stored and managed in a single license server failure of that server can result in a failure of the entire license management system Accordingly prior versions of the SENTINELLM systems include multiple license server capabilities wherein two or more license servers are provided on the network each having a pre loaded license file and a license management program One of the servers may be designated as a primary license server while the US 7 035 918 1 3 others are designated as backup servers If the primary server cannot be reached by a user for example because the primary server has crashed or otherwise gone down the user may then communicate with a backup server to obtain an authorization message The backup server having a pre loaded copy of the license file and the license management program may then take over the license management func tions Alternatively in other prior versions of SENTINELLM systems a shell program or library of API functions could be configured to send a general poll to all servers coupled to the communication channel on which the poll is sent In response to a general poll any server computer having a license file containing license information corresponding to the protected software program whether or not th
48. the example of FIG 10 after old leader server A has come back on line as a follower server according to an embodiment of the present invention DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In the following description of preferred embodiments reference is made to the accompanying drawings which form a part hereof and in which is shown by way of illustration specific embodiments in which the invention may be practiced It is to be understood that other embodi ments may be utilized and structural changes may be made without departing from the scope of the preferred embodi ments of the present invention Preferred embodiments of the invention relate to a system and process involving a pool of license servers for managing licenses to for example one or more protected software programs files or other data structures among one or more users on the network Protected software may include but is not limited to for example a software program such as a word processing program a graphics program a computer game etc a proprietary file or other data structure such as a data base or other form of data as well as other software encoded information or instructions for which the control of user access is desired For purposes of simplifying the present disclosure the protected software used in the fol lowing examples is one or more proprietary software pro grams According to a preferred embodiment of the present invention the plural
49. the invention will be apparent to those skilled in the art from the following detailed description of embodiments of the invention when read with the drawings and appended claims BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 is a generalized block diagram representation of an example network environment according to an embodiment of the present invention FIG 2 is a generalized representation of a redundant license file RLF for the network environment of FIG 1 according to an embodiment of the present invention FIG 3 is a generalized representation of a license code contained in an RLF of FIG 2 according to an embodiment of the present invention FIG 4 is a generalized representation of a license code contained in an RLF and copied into a license table and a distribution table within a single license server for the network environment of FIG 1 according to an embodiment of the present invention FIG 5 is a generalized representation of an initial state of the distribution tables of leader server A and follower servers B and C in a server pool comprising three license servers according to an embodiment of the present invention FIG 6 is a generalized representation of the distribution tables of leader server A and follower servers B and C ina server pool comprising three license servers in the example of FIG 5 after an authorization has been granted by follower server B according to an embodiment of the present inven tion FIG
50. the pool Thus attributes of the license code 26 such as the expiration date or number of allocations need not be passed between license servers 14 in response to a request for authorization to use a protected software program from a client computer 12 because an exact copy of the license code 26 has already been stored on the hard disk of each license server 14 prior to the startup of that license server 14 Each license server 14 operates under the control of its associated license management program 22 to perform license management functions in association with data con tained in the RLF 24 as described herein Thus when a particular license server 14 is started the license server 14 loads the contents of its RLF 24 into a license table 34 in RAM or other memory and reads the license table 34 which identifies that server as a license server 14 It should be noted that in preferred embodiments the license table 34 is never modified In addition the contents of the RLF 24 is loaded into a distribution table 36 in RAM or other memory and the initial distribution 30 is further copied into another record distinct from the license code 26 identified as a current distribution 40 Unlike the license table 34 the distribution table 36 changes its current distribution 40 over time to keep track of current allocations In preferred embodiments of the present invention when the license servers 14 in the server pool are first started up 5
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