[We apologize if you received multiple copies of this message] N N SSSSS M M V V 2222 NN N S MM MM V V 2 2 N N N S M M M M V V 2 N N N u u SSSSS M M M V V 2 N N N u u S M M V V 2 N NN u u S M M V V 2 N N uuuu SSSSS M M V 222222 V E R S I O N 2 . 4 . 1 (Dec 6, 2006) We are happy to announce the availability of a new version of the NuSMV model checker. NuSMV version 2.4.1 is available from http://nusmv.irst.itc.it NuSMV 2 extends the previous versions of NuSMV with several new features, most notably with the possibility of performing SAT-based Bounded Model Checking (see the OVERVIEW below). Version 2.4.1 is a minor release that provides to external contributions and some extensions to the user interface. Moreover, it fixes several bugs. ======== OVERVIEW ======== NuSMV is a reimplementation and extension of SMV, the first model checker based on BDDs. It has been designed to be an open architecture for model checking, which can be reliably used for the verification of industrial designs, as a core for custom verification tools, and as a testbed for formal verification techniques. NuSMV version 2 extends NuSMV with new model checking algorithms and techniques. It combines classical BDD-based techniques with SAT-based techniques. It also presents other new features: for instance, it allows for a more powerful manipulation of multiple models; it can generate flat models for the whole language; it allows for cone of influence reduction. The BDD-based model checking component exploits the CUDD library developed by Fabio Somenzi at Colorado University. The SAT-based model checking component includes an RBC-based Bounded Model Checker, connected to the SIM SAT library developed by the University of Genova. Optionally, NuSMV can also be used with the ZCHAFF SAT library developed by Princeton University. NuSMV version 2 is distributed with an OpenSource license, namely the GNU Lesser General Public License (LGPL). The aim is to provide a publicly available state-of-the-art symbolic model checker. With the OpenSource development model, a whole community participates in the development of a software systems, with a distributed team and independent peer review. This may result in a rapid system evolution, and in increased software quality and reliability: for instance, the OpenSource model has boosted the take-up of notable software systems, such as Linux and Apache. With the NuSMV OpenSource project, we would like to reach the same goals within the model checking community, opening the development of NuSMV. Further details on NuSMV 2 and on the NuSMV project can be found in paper: A. Cimatti, E. Clarke, E. Giunchiglia, F. Giunchiglia, M. Pistore, M. Roveri, R. Sebastiani, and A. Tacchella. "NuSMV 2: An OpenSource Tool for Symbolic Model Checking". In Proc. CAV'02, LNCS. Springer Verlag, 2002. ==== NEWS ==== This is a minor release that provides to external contributions and some extensions to the user interface. Moreover, it fixes many bugs. ---------------------------------------------------------------------- * New features ---------------------------------------------------------------------- o Improvements - Optimized LTL tableau construction (contributed by Stefano Tonetta's ) for LTL model checking via BDDs. The optimization leads to an improvement of performance of about 30% on average. Moreover, minor low-level optimizations have been also integrated to the BDD-based LTL model checking, e.g., it is now possible to reuse (default) previously computated reachable states while combining the model and the tableau FSMs. - When building the scalar fsm, variable ordering is now taken into account. This is an extension of the contribution by Wendy Johnston that initially extended NuSMV to allow the user to specify a "transition relation ordering" showing positive effects on the BDD conjunctive partioning. The ordering is taken from the BDD variable ordering by default, or it is taken from a specific "transition relation ordering" provided explicitly by the user through an option. o System commands - Added options "-f" (force) to the commands "build_boolean_model", "bmc_setup", "go", "go_bmc" and "process_model". When specified, the new option forces the corresponding model construction, even when COI is enabled. - Command 'write_boolean_model' now dumps the "current variable" ordering when the dynamic reordering had triggered. - Added command 'check_ctlspec' as an alias of 'check_spec' (that becomes deprecated) - Command 'check_pslspec' supports SBMC through new options '-s', '-c' and '-N'. See the user manual for further information. o System variables - Added system variable 'ltl_tableau_forward_search' to enable calculation of reachable states set for the LTL tableau FSM. - Added system variable 'trans_order_file' to specify an alternative variable ordering to be used for the transition relation clusterization. - Renamed system variable 'program_name' to 'program_path' to hold the complete path of the executable file that is being executed when NuSMV is running. - Added new system variable 'program_name' to hold the system ("NuSMV") name. The new variable may be used to create new interactive programs derived from NuSMV. o Command line options - Added option '-flt' to enable calculation of reachable states set for the LTL tableau FSM (see system variable ltl_tableau_forward_search). - Added option "-t " to specify an alternative variable ordering to be used for the transition relation clusterization. o SMV grammar - Added new keyword CTLSPEC as an alias of SPEC (that become deprecated). ---------------------------------------------------------------------- * Bug fixes: ---------------------------------------------------------------------- - Fixed a critical bug in CUDDs that made BDD variable groups inconsistent after a reordering. - Fixed a critical bug that affected groups creation in CUDDs - Fixed a critical bug that made booleanization being performed even when not needed, both in batch and interactive mode. Notice that the interactive mode of version 2.3.1 was also affected. - Assignment of bit selections is explicitly not handled, but trapped. - Fixed order of bits in words, that was reversed as the MSB was stored at the lowest position. - Bits of scalar variables were not grouped by default. - Operator "mod" may have boolean operands but a warning is emitted. - Dynamic reordering was erroneously disabled and got locked during encoding of input variables. - ITE (if-then-else) are now handles natively into PSL. - The command "process_model" no longer creates the boolean model. - Several fixes to the interactive shell when COI is enabled. - Fixed simulation starting from states into traces generated by BDD-based LTL model checking. The trace is stripped of the tableau variables. Warning: this fix may lead to more fake loops printed out when the trace is printed, as states that were different when tableau vars were in the trace now may become the same state after tableau vars are abstracted. - Disabling re-ordering during some specific actions (commonly executed by BMC) to prevent problems when reordering is called during the printing of a counterexample. - Fixed distributed examples there were no longer compilable due to stronger type checking rules. - Fixed some memory leaks. - Fixed implicit ordering of scalar input variables. Thanks to Andrew Miner for reporting this bug. - Fixed type checking of repeated Sere like {id [*N]} - Fixed Unary Minus operator to work on words and general expressions. - Many other minor bug fixes (see Change Log) ========= COPYRIGHT ========= NuSMV version 2 (NuSMV 2 in short) is licensed under the GNU Lesser General Public License (LGPL in short). A copy of LGPL-2.1 can be found at url . The aim of the NuSMV OpenSource project is to allow anybody interested to participate to the development of NuSMV. To this purpose, we have chosen a license that: 1) permits to use the system in research and commercial applications, without restrictions; 2) is "copyleft", that is, it requires that anyone who improves the system has to make the improvements freely available. In brief, the LGPL license allows anyone to freely download, copy, use, modify, and redistribute NuSMV 2, proviso that any modification and/or extension to the library is made publicly available under the terms of LGPL. The license also allows the usage of the NuSMV 2 as part of a larger software system *without* being obliged to distributing the whole software under LGPL. Also in this case, the modification to NuSMV 2 (*not* to the larger software) should be made available under LGPL. Notice that zchaff is for non-commercial purposes only. NO COMMERCIAL USE OF ZCHAFF IS ALLOWED WITHOUT WRITTEN PERMISSION FROM PRINCETON UNIVERSITY. Please contact Sharad Malik (malik AT ee.princeton.edu) for details. Notice also that the CUDD library is copyright University of Colorado. The CUDD library is *not* covered by LGPL. Please contact if you have any doubt or comment on the license. ======== PARTNERS ======== Different partners have participated to the initial release of NuSMV 2. Every source file in the NuSMV 2 distribution contains a header that acknowledges the developers and the copyright holders for the file. In particular: * CMU and ITC-IRST contributed the source code of NuSMV version 1; * ITC-IRST has also developed several extensions for NuSMV 2; * ITC-IRST and the University of Trento have developed the SAT-based Bounded Model Checking package of NuSMV 2; * the University of Genova has contributed SIM, a state-of-the-art SAT solver, and the RBC package used in the Bounded Model Checking algorithms. The NuSMV team has also received several contributions for different part of the system. In particular: * Ariel Fuxman has extended the LTL to SMV tableau translator to the past fragment of LTL * Rik Eshuis has contributed a strong fairness model checking algorithm for LTL specifications * Dan Sheridan has contributed several extensions and enhancements to the Bounded Model Checking algorithms. Statements of interest have also come from several other commercial and academic institutions. ================ GETTING IN TOUCH ================ The home page of the NuSMV project is . For questions, comments, or information on NuSMV, please e-mail to . For getting in touch with the NuSMV development staff, please email to . ============= MAILING LISTS ============= We maintain two mailing lists on NuSMV: * nusmv-users General questions, bugs and bug fixes, possible extensions and user requests on NuSMV can be discussed on this list. * nusmv-announce New releases and other important events for NuSMV will be announced on this list. If you are interested in the usage and in the development of NuSMV, we encourage you to subscribe to these mailing lists, using the form available at url . =========== BUG REPORTS =========== We have performed an extensive test activity on NuSMV2. Still, NuSMV is large software system and contains many interacting features. If you find a bug or misbehavior, please let us know, so that we can fix it for the next releases of NuSMV. You can use the bug report form available at url , or send an email to with the description of the bug. -- NuSMV Staff http://nusmv.irst.itc.it/