Comp.specification.z and Z FORUM Frequently Asked Questions

This appendix provides some details on how to access information on Z, particularly electronically. It has been generated from a message that is updated and sent out monthly on international computer networks. This on-line information is available on-line on the following World Wide Web (WWW) hypertext page where it is split into convenient sections and updated each month: http://www.cis.ohio-state.edu/hypertext/faq/usenet/z-faq/faq.html 1 Subject: What is it? Z (pronounced “zed”) is a formal specification notation based on set theory and first order predicate logic. It has been developed at the Programming Research Group at the Oxford University Computing Laboratory (OUCL) and elsewhere since the late 1970s. It is used by industry as part of the software (and hardware) development process in Europe, USA and elsewhere. Currently it is undergoing international ISO standardization. The comp.specification.z electronic USENET newsgroup was established in June 1991 and is intended to handle messages concerned with Z. It has an estimated readership of tens of thousands of people worldwide. Comp.specification.z provides a convenient forum for messages concerned with recent developments and the use of Z. Pointers to and reviews of recent books and articles are particularly encouraged. These may be included in the Z bibliography (see below) if they appear in comp.specification.z. 2 What if I do not have access to USENET news? There is an associated Z FORUM electronic mailing list that was initiated in January 1986 by Ruaridh Macdonald, RSRE, UK. Articles are now automatically cross-posted between comp.specification.z and the mailing list for those whose do not have access to USENET news. This may apply especially to industrial Z users who are particularly encouraged to subscribe and post their experiences to the list. Please [email protected] your name, address and email address to join the mailing list (or if you change your email address or wish to be removed from the list). Readers are strongly urged to read the comp.specification.z newsgroup rather than the Z FORUM mailing list if possible. Messages for submission to the Z FORUM mailing list and the comp.specification.z newsgroup may be emailed to [email protected]. This method of posting is particularly recommended for important messages like announcements of meetings since not all messages posted on comp.specification.z reach the OUCL. A mailing list for the Z User Meeting educational issues session has been set by Neville Dean, Anglia Polytechnic University, UK. Anyone interested may join by emailing [email protected] your contact details. 3 What if I do not have access to email? If you wish to join the postal Z mailing list, please send your address to Amanda Kingscote, Praxis plc, 20 Manvers Street, Bath BA1 1PX, UK (tel +44-1225-444700, fax +44-1225-465205, email [email protected]). This will ensure you receive details of Z meetings, etc., particularly for people without access to electronic mail. 4 How can I join in? If you are currently using Z, you are welcome to introduce yourself to the newsgroup and Z FORUM list by describing your work with Z or raising any questions you might have about Z which are not answered here. You may also advertize publications concerning Z which you or your colleagues produce. These may then be added to the master Z bibliography maintained at the OUCL (see below). 5 Where are Z-related files archived? Information on the World Wide Web (WWW) is available under the http://www.comlab.ox.ac.uk/archive/z.html page. See also the http://www.comlab.ox.ac.uk/archive/formal-methods.html page on formal methods in general. The WWW global hypermedia system is accessible using the ‘netscape’, ‘mosaic’ or ‘lynx’ programs for example. Contact your system manager if WWW access is not available on your system. Some of the Z archive is also available via anonymous FTP under ftp://ftp.comlab.ox.ac.uk/pub/Zforum (IP address 163.1.27.2 if you have access problems). The README file provides some general information and 00index gives a list of the files. If you cannot access the Internet directly, there is an automatic electronic mail-based electronic archive server which allows access to some of the Z FTP archive. Send an email message containing the command ‘help’ to [email protected] for further information on how to use the server. If you have serious trouble accessing the archive server, contact [email protected]. 6 What tools are available? Various tools for formatting, type-checking and aiding proofs in Z are available. A free LTEX style file and documentation can be obtained from the OUCL archive: ftp://ftp.comlab.ox.ac.uk/pub/Zforum/zed.sty ftp://ftp.comlab.ox.ac.uk/pub/Zforum/zguide.tex A newer style ‘csp zed.sty’ is available in the same location, which uses the new font selection scheme and covers CSP and Z symbols. A style for Object-Z ‘oz.sty’ with a guide ‘oz.tex’ is also accessible. LTEX2e users may find ‘zed-csp.sty’ and ‘zed2e.tex’ useful. The f UZZ package, a syntax and type-checker with a LTEX style option and fonts, is available from the Spivey Partnership, 10 Warneford Road, Oxford OX4 1LU, UK. It is compatible with the 2nd edition of Spivey’s Z Reference Manual. Access ftp://ftp.comlab.ox.ac.uk/pub/Zforum/fuzz for brief information and an order form. For further information, contact Mike Spivey (email [email protected]). CADiZ is a suite of integrated tools for preparing and type-checking Z specifications as professional quality typeset documents. The Z dialect it recognizes is evolving in line with the standard. The typesetting can be performed by either troff or LTEX for UNIX or Word for Windows. The mouse can be used to interact with a view of the typeset specification to inspect properties deduced by the type-checker, to see the expansion of schema calculus expressions, and to reason about conjectures such as proof obligations. The PC version is integrated with MS Word using OLE2, providing WYSIWYG editing of Z paragraphs directly in Word documents. (The troff and LTEX versions use ordinary text editors on ASCII mark-up.) Further development of the tools is ongoing. CADiZ is a BCS Award winning product available for Sun, SGI and PC machines from York Software Engineering Ltd, The InnovationCentre, York Science Park, Heslington, York, YO1 5DG, UK (email [email protected], tel +44-1904-435206, fax +44-1904435135). ProofPower is a suite of tools supporting specification and proof in Higher Order Logic (HOL) and in Z. Short courses on ProofPower-Z are available as demand arises. Information about ProofPower can be obtained automatically by sending email to [email protected]. Contact Roger Jones, International Computers Ltd, Eskdale Road, Winnersh, Wokingham, Berkshire RG11 5TT, UK (tel +44-118-969-3131 ext 6536, fax +44-118-969-7636, email [email protected]) for further details. Zola is a commercial integrated support tool for Z on Sun workstations, for automated assistance at all stages of the specification construction, proving and maintenance process. It is intended for system developers and includes a WYSIWYG editor, typechecker and tactical theorem prover suitable for the creation and maintenance of large specifications. For further information, contact Chris Paine or Will Harwood, Imperial Software Technology, 62–74 Burleigh Street, Cambridge CB1 1DJ, UK (tel +44-1223462400, fax +44-1223-462500, email [email protected]). ZTC is a Z type-checker available free of charge for educational and non-profit uses. It is intended to be compliant with the 2nd edition of Spivey’s Z Reference Manual. It accepts LTEX with ‘zed’ or ‘oz’ styles, and ZSL – an ASCII version of Z. ZANS is a Z animator. It is a research prototype that is still very crude. Both ZTC and ZANS run on Linux, SunOS 4.x, Solaris 2.x, HP-UX 9.0, DOS, and extended DOS. They are available via anonymous FTP under ftp://ise.cs.depaul.edu/pub in the directories ZANS-x.xx and ZTC-x.xx, where x.xx are version numbers. Contact Xiaoping Jia [email protected] for further information. Formaliser is a syntax-directed WYSIWYG Z editor and interactive type checker, running under Microsoft Windows, available from Logica. For further information, contact Susan Stepney, Logica UK Limited, Cambridge Division, Betjeman House, 104 Hills Road, Cambridge CB2 1LQ, UK (tel +44-1223-366343, fax +44-1223-251001, email [email protected]) or see under http://public.logica.com/ ̃formaliser/formlsr/formlsr.htm DST-fuzz is a set of tools based on the f UZZ package by Mike Spivey, supplying a Motif based user interface for LTEX based pretty printing, syntax and type-checking. A CASE tool interface allows basic functionality for combined application of Z together with structured specifications. The tools are integrated into SoftBench. For further information contact Hans-Martin Hoercher, DST Deutsche System-Techik GmbH, Edisonstr. 3, D-24145 Kiel, Germany (tel +49-431-7109-478, fax +49-431-7109-503, email [email protected]). The B-Toolkit is a set of integrated tools which fully supports the B-Method for formal software development and is available from B-Core (UK) Limited, Magdalen Centre, The Oxford Science Park, Oxford OX4 4GA, UK. Contact Ib Sørensen (tel +441865-784520, fax +44-1865-784518, email [email protected]) or see http://www.b-core.com/ Nitpick is a freely available tool for fully automatically analyzing software specifications in (roughly) a subset of Z. See http://www.cs.cmu.edu/ ̃nitpick/ Z fonts for MS Windows and Macintosh are available on-line. For hyperlinks to these and other Z tool resources see the WWW Z page: http://www.comlab.ox.ac.uk/archive/z.html#tools 7 How can I learn about Z? There are a number of courses on Z run by industry and academia. Oxford University offers industrial short courses in the use Z. As well as introductory courses, recent newly developed material includes advanced Z-based courses on proof and refinement, partly based around the B-Tool. Courses are held in Oxford, or elsewhere (e.g., on a company’s premises) if there is enough demand. For further information, contact Jim Woodcock (tel +44-1865-283514, fax +44-1865-273839, email [email protected]). Logica offer a five day Z course at company sites. Contact Rosalind Barden (tel +441223-366343 ext 4860, fax +44-1223-322315, email [email protected]) at Logica UK Limited, Betjeman House, 104 Hills Road, Cambridge CB2 1LQ, UK. Praxis Systems plc runs a range of Z (and other formal methods) courses. For details contact Anthony Hall on +44-1225-444700 or [email protected]. Formal Systems (Europe) Ltd run a range of Z, CSP and other formal methods courses, primarily in the US and with such lecturers as Jim Woodcock and Bill Roscoe (both lecturers at the OUCL). For dates and prices contact Kate Pearson (tel +44-1865728460, fax +44-1865-201114) at Formal Systems (Europe) Limited, 3 Alfred Street, Oxford OX1 4EH, UK. DST Deutsche System-Technik runs a collection of courses for either Z or CSP, mainly in Germany. These courses range from half day introductions to formal methods and Z to one week introductory or advanced courses, held either at DST, or elsewhere. For further information contact Hans-Martin Hoercher, DST Deutsche System-Techik GmbH, Edisonstr. 3, D-24145 Kiel, Germany (tel +49-431-7109-478, fax +49-4317109-503, email [email protected]). 8 What has been published about Z? A searchable on-line Z bibliography is available on the World Wide Web under http://www.comlab.ox.ac.uk/archive/z/bib.html in BIBTEX format. The following books largely concerning Z have been or are due to be published (in approximate chronological order): I. Hayes (ed.), Specification Case Studies, Prentice Hall International Series in Computer Science, 1987. (2nd ed., 1993) URL: http://www.prenhall.com/013/832543/ptr/83254-3.html J. M. Spivey, Understanding Z: A specification language and its formal semantics, Cambridge University Press, 1988. D. Ince, An Introduction to Discrete Mathematics, Formal System Specification and Z, Oxford University Press, 1988. (2nd ed., 1993) J. C. P. Woodcock & M. Loomes, Software Engineering Mathematics: Formal Methods Demystified, Pitman, 1998. (Also Addison-Wesley, 1989) J. M. Spivey, The Z Notation: A reference manual, Prentice Hall International Series in Computer Science, 1989. (2nd ed., 1992) [Widely used as a de facto standard for Z. Often known as ZRM2.] A. Diller, Z: An introduction to formal methods, Wiley, 1990. J. E. Nicholls (ed.), Z user workshop, Oxford 1989, Springer-Verlag, Workshops in Computing, 1990. B. Potter, J. Sinclair & D. Till, An Introduction toFormal Specification and Z, Prentice Hall International Series in Computer Science, 1991. (2nd ed., 1996) URL: http://www.prenhall.com/013/242206/ptr/24220-6.html D. Lightfoot, Formal Specification using Z, MacMillan, 1991. A. Norcliffe & G. Slater, Mathematics for Software Construction, Ellis Horwood, 1991. J. E. Nicholls (ed.), Z User Workshop, Oxford 1990, Springer-Verlag, Workshops in Computing, 1991. I. Craig, The Formal Specification of Advanced AI Architectures, Ellis Horwood, 1991. M. Imperato, An Introduction to Z, Chartwell-Bratt, 1991. J. B. Wordsworth, Software Development with Z, Addison-Wesley, 1992. S. Stepney, R. Barden & D. Cooper (eds.), Object Orientation in Z, Springer-Verlag, Workshops in Computing, August 1992. URL: http://public.logica.com/ ̃stepneys/bib/ss/ooz.htm J. E. Nicholls (ed.), Z User Workshop, York 1991, Springer-Verlag, Workshops in Computing, 1992. URL: http://www.imi.gla.ac.uk/springer/eWiC/Abstracts/9.html D. Edmond, Information Modeling: Specification and implementation, Prentice Hall, 1992. J. P. Bowen & J. E. Nicholls (eds.), Z User Workshop, London 1992, Springer-Verlag, Workshops in Computing, 1993. URL: http://www.comlab.ox.ac.uk/archive/z/zum92.html S. Stepney, High Integrity Compilation: A case study, Prentice Hall, 1993. URL: http://public.logica.com/ ̃stepneys/bib/ss/hic.htm M. McMorran & S. Powell, Z Guide for Beginners, Blackwell Scientific, 1993. K. C. Lano & H. Haughton (eds.), Object-oriented Specification Case Studies, Prentice Hall International Object-Oriented Series, 1993. B. Ratcliff, Introducing Specification using Z: A practical case study approach, McGraw-Hill, 1994. A. Diller, Z: An introduction to formal methods, 2nd ed., Wiley, 1994. J. P. Bowen & J. A. Hall (eds.), Z User Workshop, Cambridge 1994, Springer-Verlag, Workshops in Computing, 1994. URL: http://www.comlab.ox.ac.uk/archive/z/zum94.html R. Barden, S. Stepney & D. Cooper, Z in Practice, Prentice Hall BCS Practitioner Series, 1994. URL: http://public.logica.com/ ̃stepneys/bib/ss/zip.htm D. Rann, J. Turner & J. Whitworth, Z: A beginner’s guide. Chapman & Hall, 1994. D. Heath, D. Allum & L. Dunckley, Introductory Logic and Formal Methods. A. Waller, Henley-on-Thames, 1994. L. Bottaci and J. Jones, Formal Specification using Z: A modelling approach. International Thomson Publishing, 1995. D. Sheppard, An Introduction to Formal Specification with Z and VDM. McGraw Hill International Series in Software Engineering, 1995. J. P. Bowen & M. G. Hinchey (eds.), ZUM’95: The Z Formal Specification Notation, Springer-Verlag, Lecture Notes in Computer Science, volume 967, 1995. URL: http://www.comlab.ox.ac.uk/archive/z/zum95.html J. P. Bowen, Formal Specification and Documentation using Z: A Case Study Approach, International Thomson Compress Press, 1996. URL: http://www.comlab.ox.ac.uk/oucl/users/jonathan.bowen/zbook.html J. C. P. Woodcock & J. Davies, Using Z: Specification, proof and refinement, Prentice Hall International Series in Computer Science, 1996. URL: http://www.comlab.ox.ac.uk/usingz.html A. Harry, Formal Methods Fact File: VDM and Z, Wiley, 1996. J. Jacky, The Way of Z: Practical Programming with Formal Methods, Cambridge University Press, 1997. URL: http://www.radonc.washington.edu/prostaff/jon/z-book/ See also an on-line list of Z books from Blackwells Bookshop under: http://www.blackwell.co.uk/cgi-bin/bb catsel?09 IBY Formal Methods: A Survey by S. Austin & G. I. Parkin, March 1993 includes information on the use and teaching of Z in industry and academia. Contact DITC Office, Formal Methods Survey, National Laboratory, Teddington, Middlesex TW11 0LW, UK (tel +44-181-943-7002, fax +44-181-977-7091) for a copy. Oxford University Computing Laboratory Technical Monographs and Reports, including many on Z, is available from the OUCL librarian (tel +44-1865-273837, fax +44-1865-273839, email [email protected]). For information on formal methods publications in general, see: http://www.comlab.ox.ac.uk/archive/formal-methods/pubs.html 9 What is object-oriented Z? Several object-oriented extensions to or versions of Z have been proposed. The book Object orientation in Z, listed above, is a collection of papers describing various OOZ approaches – Hall, ZERO, MooZ, Object-Z, OOZE, Schuman&Pitt, Z , ZEST and Fresco (an OO VDM method) – in the main written by the methods’ inventors, and all specifying the same two examples. A more recent book entitled Object-oriented specification case studies surveys the principal methods and languages for formal objectoriented specification, including Z-based approaches.