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FAQ: BETA Programming Language (version 1.11 - 08 Dec 97)

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BETA: Frequently Asked Questions (FAQ)

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This question-and-answer list is posted regularly to the BETA mail group,
and to the Usenet newsgroups comp.lang.beta, comp.answers, and news.answers.

Please send corrections, additions and comments to Jorgen Lindskov Knudsen
(jlk@daimi.aau.dk).

This information is abstracted and condensed from the posts of many
different contributors. No guarantees are made regarding its accuracy.
----------------------------------------------------------------------------
There are several ways to get this document:

   * E-mail: The FAQ can be obtained by sending a message to
     info@mjolner.com with the following message body:

        send BETA beta-language-faq

   * FTP: The FAQ can be fetched via anonymous ftp from ftp.daimi.aau.dk as

        pub/beta/faq/beta-language-faq.txt

   * WWW: The FAQ is available in hypertextualized form on the World Wide
     Web at URL

        http://www.daimi.aau.dk/~beta/FAQ.

     (This site always contains the most recent version.)

More information on BETA can be found on:

   * The BETA Home Page:

        http://www.daimi.aau.dk/~beta/

   * The Mjolner System Home Page:

        http://www.mjolner.com/

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Changes since version 1.10

New entries:

   * Why does my guienvsystemenv program stop at startup? (B09)
   * What is the maximum length of a BETA identifier? (L24)
   * What is the exact qualification rules for nested patterns? (L25)
   * Does BETA work on Motorola machines? (M05)
   * Known bugs, limitations and inconveniences in release 4.0.2 (W06)
   * Known bugs, limitations and inconveniences in release 4.1 (W07)
   * What are the system requirements to run BETA on HPUX workstations?
     (HP01)
   * What are the system requirements to run BETA on Linux machines? (Lx01)
   * Why does GuiEnv demos segmentation fail? [error in r4.0 & r4.0.1]
     (Lx03)
   * What are the system requirements to run BETA on Sun workstations?
     (Sun01)
   * Using BETA on IRIX 6 machines(SG04)
   * How to format BETA programs in LaTeX? (Q19)
   * xxx? (ref)
   * New features in version 5.3 of the Compiler (C14.1)

Changed entries:

   * What are the system requirements to run BETA on Macintosh? (M01)
   * What is MPW. Where do I get it? (M02)
   * Does BETA work on PowerPC machines? (M04)
   * SDK Requirements for Windows 95 or Windows NT (W02) [Updated info
     related to r4.0.1]
   * Limitations, bugs and inconveniences (SG05)
   * Disclaimer (Slow startup of tools) (SG06)
   * xxx? (ref)

Removed entries:

   * System Requirements for specific platforms (old Q19)

In addition, a number of minor changes and corrections have been made to
other entries.
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Contents

   * Part I: Frequently Asked Questions
        o Q01) What is BETA?
        o Q02) Where did BETA come from?
        o Q03) What BETA products are available?
        o Q04) Are there any school or student discounts?
        o Q05) Is BETA available in the public domain?
        o Q06) What books are available for learning about BETA?
        o Q07) Does an introduction to BETA besides the BETA book exist?
        o Q08) Are any magazines or newsletters concerning BETA available?
        o Q09) Are there any user groups related to BETA?
        o Q10) Are there any mailing lists related to BETA?
        o Q11) Are there any newsgroups related to BETA?
        o Q12) Is there an archive of BETA postings?
        o Q13) Are there any conferences for BETA users?
        o Q14) Is BETA available on PC, Mac, NeXT, Amiga, Atari, ...?
        o Q15) Are there standards for the BETA language?
        o Q16) What is Mjolner, Sif, Valhalla, Bifrost, Yggdrasil, etc.?
        o Q17) Is it possible to obtain an evaluation version of the Mjolner
          System?
        o Q18) What is the origin of the name BETA?
        o Q19) How to format BETA programs in LaTeX?
   * Part II: Language Issues
        o L01) What features do BETA have?
        o L02) What changes have been made to the BETA language definition?
        o L03) How do I deal with concurrency in BETA?
        o L04) How do I deal with persistence in BETA?
        o L05) How do I deal with distribution in BETA?
        o L06) How do I deal with exception handling in BETA?
        o L07) Can classes be treated as first-order elements in BETA?
        o L08) What about garbage collection in BETA?
        o L09) How do I create a "parameterized class"?
        o L10) What is the difference between a virtual binding, a further
          binding and a final binding (i.e. between :<, ::<, and ::)?
        o L11) What about invariants in BETA?
        o L12) What about change propagation in BETA?
        o L13) What about futures in BETA?
        o L14) Why can't local variables be accessed in INNER?
        o L15) How do I implement a copy (or clone) operation?
        o L16) Why doesn't BETA have multiple inheritance?
        o L17) What is the rationale behind the syntax of BETA?
        o L18) How do the scope rules of BETA actually work?
        o L19) What is a pattern?
        o L20) Are identifiers and keyworks case-sensitive in BETA?
        o L21) What characters are allowed in BETA identifiers?
        o L22) What is the exact semantics of leave P and restart P, when P
          is the name of a pattern?
        o L23) What is the BETA lexem syntax?
        o L24) What is the maximum length of a BETA identifier?
        o L25) What is the exact qualification rules for nested patterns?
   * Part III: Environment Issues
        o E01) What is the Mjolner System?
        o E02) What does the Mjolner System contain?
        o E03) What libraries come with the Mjolner System?
        o E04) What frameworks come with the Mjolner System?
        o E05) What tools come with the Mjolner System?
        o E06) Does a beta-mode for Emacs exist?
   * Part IV: Specific Issues
        o Section I: The Fragment System
             + F01) What is the purpose of the fragment system?
             + F02) How do I separate implementation and specification code?
             + F03) How do I work around "*****Only pattern-declarations may
               appear in a fragment of category 'attributes'"?
             + F04) Why can't I have instances in attributes-fragments?
             + F05) Why can't I have virtual declarations/bindings in
               attributes-fragments?
             + F06) What are the differences between the INCLUDE facilities
               of BETA and C?
             + F07) Why doesn't the compiler complain about a missing inner
               in a body fragment?
             + F08) Can <> be used instead of <>?
        o Section II: The X libraries
             + X01) Why does my label widget sometimes get the attribute
               name as label-string, and sometimes not?
             + X02) Why do I get the error "There must be only one non-shell
               widget which is son of Toplevel"?
             + X03) How do I get a separate window for my widget?
             + X04) Why do I get the error "clockWidgetClass: undefined"
               when linking my AwEnv program? [corrected in r4.0]
             + X05) Why do I get the error "Error: NULL ArgVal in
               XtGetValues" when executing my Xt program? [corrected in
               r4.0]
             + X06) How do I set font information in MotifStrings?
             + X07) Resource specification errors in Xt/v1.9
        o Section III: The BETA compiler
             + C01) What is the execution speed of BETA programs?
             + C02) How do I get rid of the warning: "A run-time
               qualification check will be inserted here"?
             + C03) What *does* that Qua-check warning mean, anyway?
             + C04) How do I work around "*****Repetition of non simple
               patterns is not implemented"? [corrected in r4.0]
             + C05) How do I work around "Labeled imperative not
               implemented"?
             + C06) Why does a BETA program called test.bet cause problems
               on some UNIX installations?
             + C07) How do I disable qualification check warnings?
             + C08) What is the difference between P and &P?
             + C09) What does "virtual prefix not implemented" mean?
               [corrected in r4.0]
             + C10) What should I do if the compiler prints "Please report
               the error to Mjolner Informatics" and stops?
             + C11) What are the known errors the compiler?
                  + C11.1) Bugs in version 5.0
                  + C11.2) Bugs in version 5.1
                  + C11.3) Bugs in version 5.2
             + C12) Tracing the work of compiler?
             + C13) Problem with floating point expressions in connection
               with repetitions
             + C14) New features introduced in the Compiler
                  + C14.1) New features in version 5.3 of the Compiler
                  + C14.2) New features in version 5.2 of the Compiler
                  + C14.3) New features in version 5.1 of the Compiler
                  + C14.4) New features in version 5.0 of the Compiler
        o Section IV: The Basic libraries
             + B01) How do you compare text strings in BETA?
             + B02) How do you read and write text in BETA?
             + B03) Why does getInt followed by getLine not necessarily work
               as expected?
             + B04) What is the rationale behind the Mjolner System file
               directory structures?
             + B05) What do the (* idx+ *), etc. comments mean?
             + B06) Error in v1.4/seqContainer.bet? [corrected in r4.0]
             + B07) Error in v1.4/regexp.bet? [corrected in r4.0]
             + B08) Error in v1.4/basicsystemenv.bet? [corrected in r4.0]
             + B09) Why does my guienvsystemenv program stop at startup?
   * Part V: Platform Specific Issues
        o Section V: BETA on Macintosh
             + M01) What are the system requirements to run BETA on
               Macintosh?
             + M02) What is MPW. Where do I get it?
             + M03) Do I need a floating point unit to use BETA?
             + M04) Does BETA work on PowerPC machines?
             + M05) Does BETA work on Motorola machines?
             + M06) Known bugs, limitations and inconveniences in release
               4.0.2
             + M07) Known bugs, limitations and inconveniences in release
               4.1
        o Section VI: BETA on Windows 95 and Windows NT
             + W01) What are the system requirements to run BETA on Windows
               95 and Windows NT?
             + W02) SDK Requirements for Windows 95 or Windows NT
             + W03) Why do I need a MAKE facility?
             + W04) Error in directory scan using Borland SDK? [corrected in
               r4.0]
             + W05) Make-error for lazyref_gc.c using Borland SDK?
               [corrected in r4.0.2]
             + W06) Known bugs, limitations and inconveniences in release
               4.0.2
        o Section VII: BETA on HPUX
             + HP01) What are the system requirements to run BETA on HPUX
               workstations?
             + HP02) Why do some callbacks cause "Illegal Instruction" on
               hpux9pa (using v5.0 of the compiler)?
        o Section VIII: BETA on Linux
             + Lx01) What are the system requirements to run BETA on Linux
               machines?
             + Lx02) How to make the BETA compiler version 5.0/5.1 work with
               Linux ELF libraries [corrected in r4.0]
             + Lx03) Why does GuiEnv demos segmentation fail? [error in r4.0
               & r4.0.1]
        o Section IX: BETA on Silicon Graphics
             + SG01) What are the system requirements to run BETA on Silicon
               Graphics workstations?
             + SG02) Gnu C Compiler gcc not supported
             + SG03) Remember to set LD_LIBRARY_PATH
             + SG04) Using BETA on IRIX 6 machines
             + SG05) Limitations, bugs and inconveniences
             + SG06) Disclaimer (Slow startup of tools)
        o Section X: BETA on Sun workstations
             + Sun01) What are the system requirements to run BETA on Sun
               workstations?

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PART I: Frequently Asked Questions

----------------------------------------------------------------------------

Q01) What is BETA?

BETA is a modern object-oriented language with comprehensive facilities for
procedural and functional programming. BETA has powerful abstraction
mechanisms than provide excellent support for design and implementation,
including data definition for persistent data. The abstraction mechanisms
include support for identification of objects, classification, and
composition. BETA is a strongly typed language (like Simula, Eiffel, and
C++), with most type checking being carried out at compile-time.

The abstraction mechanisms include class, procedure, function, coroutine,
process, exception, and many more, all unified into the ultimate abstraction
mechanism: the pattern. In addition to the pattern, BETA has subpattern,
virtual pattern, and pattern variable.

BETA does not only allow for passive objects as in Smalltalk, C++, and
Eiffel. BETA objects may also act as coroutines, making it possible to model
alternating sequential processes and quasi-parallel processes. BETA
coroutines may also be executed concurrently with supported facilities for
synchronization and communication, including monitors and rendezvous
communication.
----------------------------------------------------------------------------

Q02) Where did BETA come from?

BETA originates from the Scandinavian school of object-orientation where the
first object-oriented language Simula was developed. Object-oriented
programming originated with the Simula languages developed at the Norwegian
Computing Center, Oslo, in the 1960s. The first Simula language, Simula I,
was intended for writing simulation programs. Simula I was later used as a
basis for defining a general-purpose programming language, Simula 67 (later
renamed to Simula). Simula has been used by a relatively small community for
a number of years, although it has had a major impact on research in
computer science.

The BETA language development process started out in 1975 with the aim to
develop concepts, constructs and tools for programming, partly based on the
Simula languages. The BETA language team consists of Bent Bruun Kristensen,
Birger Moller-Pedersen, Ole Lehrmann Madsen, and Kristen Nygaard. Kristen
Nygaard was one of the two original designers of the Simula languages.
----------------------------------------------------------------------------

Q03) What BETA products and services are available?

Currently there is only one supplier of BETA products, namely Mjolner
Informatics, who is marketing an entire development system (the Mjolner
System) based on the BETA language.

In the US, the MacTech Magazine Mail Store is the distributor of the Mjolner
System.

In France and the French parts of Belgium and Switzerland, the Mjolner
System is distributed by BCDL-ObjectLand.

In UK, the Mjolner System is distributed by InterGlossa.

Mjolner Informatics offers the Mjolner System technology to other commercial
organizations who are interested in building BETA products (such as
alternative development systems), or who are interested in developing
value-added products for the Mjolner System. This offer is based on
licensing of the implementation of the existing system (including source
code, if needed).

     Mjolner Informatics
          Gustav Wieds Vej 10
          DK-8000 Aarhus C
          Denmark
          Phone: +45 86 12 20 00
          Fax: +45 86 12 20 22
          E-mail: info@mjolner.com
          WWW: http://www.mjolner.com
          WWW Sales: http://www.mjolner.com/warehouse/

     MacTech Magazine, Mail Order Store
          Xplain Corporation
          P.O. Box 250055
          1617 Pontius Avenue, 2nd Floor
          Los Angeles, CA 90025-9555, USA
          Phone: +1 310 575 4343
          Fax: +1 310 575 0925
          AppleLink: MACTECHMAG
          CompuServe: 71333,1064
          Internet: neil_ticktin@xplain.com
          America Online: MACTECHMAG
          GEnie: MACTECHMAG

     BCDL-ObjectLand
          26 rue Jules Lanery
          F-59240 Dunkerque
          France
          Phone: +33 28 66 53 00
          Fax: +33 28 66 53 01
          E-mail: ObjectLand@netinfo.fr
          WWW: http://www.netinfo.fr/ObjectLand/ (Journal of
          ObjectLand, the newsletter)
          WWW: http://www.netinfo.fr/BCDL/ (Home Page of BCDL)

     InterGlossa Ltd
          59, Alexandra Road
          Reading RG1 5PG
          UK
          Phone: +44 1734 561919
          Fax: +44 1734 561920
          E-mail: Tom.Lake@glossa.co.uk
          WWW: http://www.glossa.co.uk

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Q04) Are there any school or student discounts?

Mjolner Informatics offers substantial discounts for educational purposes
(e.g. 45/%}. Also included in educational site licenses are attractive
offers for the institutions to freely distribute Personal Edition versions
of the system to those students, following the cources, in which BETA is
used.

Generally, the Personal Edition versions of the system is freely available
directly from Mjolner Informatics. Visit the download area for more
information.
----------------------------------------------------------------------------

Q05) Is BETA available in the public domain?

The BETA language definition is in the public domain. A reference manual on
the language is in progress (release-date not fixed yet).

The Personal Edition versions of the system is freely available from Mjolner
Informatics. Visit the download area for more information.

Kai Petzke has initiated a project for writing a freeware compiler for BETA.
It is implemented as a translator of BETA to C. For more information and to
download a working copy of the compiler, that understands most of BETA's
grammatical terms, see the web page:
http://troubadix.physik.tu-berlin.de/~petz0433/beta/eindex.html.
----------------------------------------------------------------------------

Q06) What books are available for learning about BETA?

The ultimate source of information on the BETA language is:

     Ole Lehrmann Madsen, Birger Moller-Pedersen, Kristen Nygaard:
     "Object-Oriented Programming in the BETA Programming Language"
     Addison-Wesley and ACM Press, 1993
     ISBN 0-201-62430-3

An german introduction to BETA can be found in the book:

     Ernst Erich Doberkat, Stefan Dißmann:
     "Einführung in die objectkorientierte Programmierung mit BETA"
     Addison-Wesley-Longman, 1996
     ISBN 3-8273-1026-1

The Mjolner System and the BETA language is also extensively described in
the book:

     Jorgen Lindskov Knudsen, Mats Lofgren, Ole Lehrmann Madsen, Boris
     Magnusson (eds.):
     "Object-Oriented Environments: The Mjolner Approach"
     Prentice-Hall, 1993
     ISBN 0-13-009291-6

----------------------------------------------------------------------------

Q07) Does an introduction to BETA besides the BETA book exist?

The previously mentioned book: "Object-Oriented Environments: The Mjolner
Approach" contains an introductory chapter on the BETA language.

Besides, various current activities indicate that introductory material in
the form of tutorials are in the pipeline.

See also question Q08.
----------------------------------------------------------------------------

Q08) Are any magazines or newsletters concerning BETA available?

The BETA language has been presented in several conference papers, including
the OOPSLA, ECOOP, and TOOLS conferences. BETA has also been described in a
couple of articles in Dr. Dobb's Journal, #206, October 1993. Furthermore,
Communications of the ACM, Vol. 37, No. 2, February 1994, is a special issue
on Hypermedia, including three papers on the use of the Mjolner System (and
the BETA language) for building hypermedia systems.

Mjolner Informatics produces a quarterly 8-page newsletter called "Mjolner
BETA Newsletter".
----------------------------------------------------------------------------

Q09) Are there any user groups related to BETA?

Yes, there is a user group hosted by Mjolner Informatics. The user group is
primarily organized around the BETA mailing list: usergroup@mjolner.com

The BETA user group is one of the important sources of information on the
developments of the Mjolner System, and an important source of information
to Mjolner Informatics on the users' expectations for future developments.

See also question Q10.
----------------------------------------------------------------------------

Q10) Are there any mailing lists related to BETA?

There is a mailing list for BETA, organized by Mjolner Informatics:

   usergroup@mjolner.com

In order to be added to, or removed from the mailing list, please send a
mail to:

   usergroup-request@mjolner.com

(Do not send subscription requests to usergroup@mjolner.com as they will be
mirrored onto comp.lang.beta.)

Mail sent to the mailing list is automatically forwarded to the
comp.lang.beta newsgroup and news posted on the newsgroup is automatically
forwarded (moderated) to the mailing list.
----------------------------------------------------------------------------

Q11) Are there any newsgroups related to BETA?

The comp.lang.beta Usenet newsgroup is available for discussing issues
related to the BETA language.

Postings to comp.lang.beta are automatically forwarded (moderated) to the
usergroup@mjolner.com mailing list and mails to the mailing list is
automatically posted to the newsgroup.
----------------------------------------------------------------------------

Q12) Is there an archive of BETA postings?

Mjolner Informatics keeps an archive of the BETA mailing list.

In addition, the University of Aarhus maintains an archive of all postings
to the comp.lang.beta newsgroup, available at:

   * http://www.daimi.aau.dk/~beta/News/
   * ftp://ftp.daimi.aau.dk/pub/beta/comp.lang.beta

The former is updated daily, the latter annually.
----------------------------------------------------------------------------

Q13) Are there any conferences for BETA users?

There are no conferences devoted entirely to the BETA language and
development system. BETA shares the spotlight with other object-oriented
languages including C++, Eiffel, and Smalltalk in conferences like:

TOOLS
     the major international conference devoted to the applications of
     Object-Oriented technology.
ECOOP
     the European Conference on Object-Oriented Programming.
OOPSLA
     the major international conference on Object-Oriented Programming,
     Systems, Languages, and Applications.

----------------------------------------------------------------------------

Q14) Is BETA available on PC, Mac, NeXT, Amiga, Atari, ...?

Currently, BETA is available on UNIX workstations, on PowerPC Macintosh and
on Intel-based PCs.

On UNIX, the platforms supported are: Sun Sparc (Solaris), HP 9000 (series
700) and Silicon Graphics MIPS machines running IRIX 5.3 or 6.

Mjolner System is also available for Linux (386/486/Pentium). Linux is a
very popular freely available UNIX implementation for Intel processors (for
more information, see the Linux FAQ).

Mjolner System is also available for Windows 95 and Windows NT
(386/486/Pentium).

There are no current plans to port the Mjolner System to neither DOS nor
Windows 3.1 due to the 16-bit addressing and 8-character filename
limitations.

Although not officially confirmed by Mjolner Informatics, users of the
Mjolner System have reported that the Mjolner System can be effectively used
on Amiga 4000 machines under the MacOS simulator, with an execution speed
reported to be comparable to that of an HP 9000/425 workstation.

The following additional info is kindly supplied by Juha Makinen
:

     Actually this program is an emulator, because it can run native
     Apple Macintosh 680x0-code in Amigas. The name of this program is
     an Emplant and it is a 99,9% compatible Apple Macintosh emulator.
     It emulates the Machintosh (like Quadra) even faster than an
     equivalent Macintosh is running with the same processor and
     clock-speed. (This is due to separate graphics, I/O etc.
     co-processors found on motherboard of the Amiga. Some programs
     show two times better performance.)

     The program is an multi-platform -emulator and can also multitask
     another emulation and/or AmigaOS on the backgroud. There is a
     rival (Amax IV) for this emulation-program, but it is only 99,5%
     Macintosh-compatible and is not supported as widely as this one
     is. (I'm not sure which one the original author refers to, but I'm
     quite sure that you can run Beta-compiler on Emplant with
     Macintosh Emulation. Every program which run in original Quadra
     should run on Emplant.)

     And as an addition, you can run Emplant-emulator also on the Amiga
     3000 (and A2000 if you have a processor-card with MMU).

----------------------------------------------------------------------------

Q15) Are there standards for the BETA language?

The definition of the BETA language is in the public domain. This definition
is controlled by the original designers of the BETA language: Bent Bruun
Kristensen, Ole Lehrmann Madsen, Birger Moller-Pedersen, and Kristen
Nygaard. This means that anyone or any company may create a compiler,
interpreter, or whatever having to do with BETA.

Currently, no language definition document exist. Work is in progress to
write this language definition document. The definition will be given in
strict natural language.

See section Q06 and L02 for information on available language descriptions
and latest changes to the language.

The BETA and the Mjolner System trademarks are owned and controlled by
Mjolner Informatics.
----------------------------------------------------------------------------

Q16) What is Mjolner, Sif, Valhalla, Bifrost, Yggdrasil, etc.?

Many have wondered about the origins of the strange product names used for
parts of the Mjolner System. Due to the origin of the Mjolner BETA System,
many of the components of the system bear Nordic names. These Nordic names
originate from the Nordic Mythology, and are thus names within the common
cultural background of people in the entire Nordic region:

Mjolner:
     is the name of the hammer of the god Thor. According to the Mythology,
     this hammer is the perfect tool that cannot fail, that grows with the
     task, and always returns to the hand of Thor if he throws it at
     something. Finally about the pronunciation of Mjolner. For English
     speaking people, the "spelling of the pronunciation" could be:
     "Myolner" or "Myulner", and for French speaking people it could be:
     "Mieulnor".
Yggdrasil:
     is the name of the Tree of the World, the ash tree of which the crown
     covers the whole world. The tree gets it power from the gods, from the
     evil giants, and from the kingdom of the dead. Everything in the world
     happens under the mighty crown of Yggdrasil. Yggdrasil is the name of
     the metaprogramming system.
Bifrost:
     is the name of the luminous bridge, the rainbow, that leads from
     Midgaard to Asgaard. Midgaard is the place where the human beings live,
     and Asgaard is the habitat of the Gods in the middle of the world.
     Bifrost is the name of the graphics system.
Valhalla:
     is the name of Odin's hall to where all dead warriors come when they
     have fallen as heroes on the battlefield. Valhalla is the name of the
     source-level debugger.
Sif:
     is the name of the wife of Thor. Sif is famous for her golden hair. Sif
     is the name of the hyper structure editor.
Freja:
     is the name of the goddess of love. She lives in Folkvang and is the
     most beautiful of all women in Asgaard. She owns the golden piece of
     jewelry Brisingemen. Freja is the name of the CASE tool.
Frigg:
     is the name of the wife of Odin and queen of Asgaard. Frigg is the name
     of the user interface editor.
Odin:
     is the name of the highest ranking god in Asgaard.
Thor:
     is the name of the strongest of all gods. He is the god for all
     peasants. He is the son of Odin and Frigg and lives together with his
     wife Sif in Trudvang on the farm Bilskirner which is the biggest house
     in the world, with 540 floors.

----------------------------------------------------------------------------

Q17) Is it possible to obtain an evaluation version of the Mjolner System?

Well, yes and no. Mjolner Informatics has previously offered a demo version
of the Mjolner System for the cost of media and shipment.

Due to the introduction of the very cheap Personal Edition versions on all
platforms, the demo offer has, however, been stopped. For evaluation
purposes, Mjolner Informatics suggests purchase of a PE system (price
currently US$ 60+VAT, media and shipment). Write info@mjolner.com for
details.
----------------------------------------------------------------------------

Q18) What is the origin of the name BETA?

[Ole Lehrmann Madsen (olm@daimi.aau.dk) writes:]

Originally Beta was just one of a series of languages developed at Nordic
universities.

The first object-oriented language Simula was originally designed as a
simulation language but it was soon realised that the main ideas could be
used for programming in general and this lead to Simula 67, which has class,
subclass, virtual function coroutines, etc. It also supplied the first
object-oriented framework in the form of Class Simulation which is a set of
classes to support the original goal of Simula to write simulation programs.

It turned out that many users of Simula seemed to get more understanding of
their problem domain by having to develop a model using Simula than of the
actual simulation results.

Kristen Nygaard and others then decided to develop a successor for Simula,
but with main focus of system description - not execution. This lead to a
language called

     Delta

In Delta you could express true concurrent objects and use predicates to
express state changes. Delta could, however, not be executed. Delta means

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