Why do I get the error "UnsupportedAlgoId" when processing MOS data?

The explanation below (under "FORMER EXPLANATION") was made obsolete by the release of the patch to SAS 6.5 - A new set of CCFs describing the MOS redistribution function (EMOS[1-2]_REDIST_00[65][74]) has been made public, to be used with a patched SAS 6.5, on December 1st, 2005. If you get the error "UnsupportedAlgoId" after this date it is due to the presence of those files in your CCF repository. To be able to use them you need an update of the SAS 6.5 using the patch.

FORMER EXPLANATION:
A set of CCFs which describe the MOS redistribution function (EMOS1_REDIST_0061,0062,0063,0064 and EMOS2_REDIST_0061,0062,0063,0064) were accidentally released to the public area on October 1st. These have been prepared for a new release of the SAS and are deliberatley not compatible with SAS version 6.5.0 or earlier.

If these files are used with the current SAS then an error message is produced of the form:
** backscale::arfgen: fatal error (UnsupportedAlgoId), The table/array `/software/XMM/ccf/EMOS1_REDIST_0063.CCF:CCD_REDISTRIBUTION-1' specifies ALGOID=2 but this version of the CAL merely supports 0<=ALGOID<=1 - you may want to upgrade to a more recent version of the CAL that knows about the reported ALGOID.

The solution is to manually remove these CCF elements from your public CCF area. If this is done then the SAS will revert to using earlier CCF elements which are fully compatible with SAS 6.5.0 but not with SAS 6.1 (see the corresponding watchout).