Noble-Soft Systems endeavours to ensure that the ANSWER-MARKAL software is bug-free and that the ANSWER-MARKAL User Manuals and other supporting material (databases and information updates) provide easily understood documentation of the software’s facilities.

Noble-Soft gives a high priority to correcting bugs in its software, or where a bug cannot be quickly corrected, to providing a work-around. Noble-Soft also gives a priority to correcting and improving the documentation to address any problems or shortcomings observed.

If you suspect that you may have encountered an ANSWER-MARKAL bug, please contact Dr. Ken Noble ( providing as much information as you are able to about the circumstances that lead you to suspect a bug. Screen snapshots can be very helpful.

If there are aspects of the operation of the ANSWER-MARKAL software that are not clear to you after studying the relevant ANSWER-MARKAL User Manual or supporting material please contact Dr. Ken Noble ( who will endeavour to quickly resolve any issue.

Please always provide the version of the ANSWER-MARKAL EXE that you are using (“Help, About ANSWER”) when contacting Noble-Soft with queries about bugs or the documentation.

MARKAL Support

A number of avenues are available for obtaining support if you have queries relating to the MARKAL model itself (as distinct from queries relating to the operation of the ANSWER-MARKAL software):

  • Limited support is available from ETSAP by contacting Non-ETSAP institutions who are interested in receiving more substantial support for the development of models based on ETSAP’s MARKAL model generator may request ETSAP Support for the payment of an annual fee.
  • Also ETSAP has a discussion Forum (click on the Forum tab on the ETSAP home page -
  • While Noble-Soft’s primary focus is on development of the ANSWER software, if you have a query about a specific aspect of the MARKAL model, we will attempt to answer it, and if unable to answer it ourselves will endeavour to obtain the answer from one of our ETSAP colleagues who is knowledgeable in MARKAL.
  • For issues related to GAMS, the programming language in which MARKAL is written, you may contact Mr. Gary Goldstein, the ETSAP Liaison Officer (

Noble-Soft regrets that in general it is unable to address queries such as why a user’s MARKAL model in an ANSWER-MARKAL database is not behaving as expected. That said, Noble-Soft sometimes provides limited assistance with such queries to ANSWER-MARKAL beginners who send along small databases seeking help with a specific aspect of MARKAL.