def buildFileListOrig(input, output=None, ivmlist=None,
                wcskey=None, updatewcs=True, **workinplace):
    """
    Builds a file list which has undergone various instrument-specific
    checks for input to MultiDrizzle, including splitting STIS associations.
    Compared to buildFileList, this version returns the list of the
    original file names as specified by the user (e.g., before GEIS->MEF, or
    WAIVER FITS->MEF conversion).
    """
    # NOTE: original file name is required in order to correctly associate
    # user catalog files (e.g., user masks to be used with 'skymatch') with
    # corresponding imageObjects.

    filelist, output, ivmlist, oldasndict = processFilenames(input,output)

    # verify that all input images specified can be updated as needed
    filelist = util.verifyFilePermissions(filelist)
    if filelist is None or len(filelist) == 0:
        return None, None, None, None, None

    manageInputCopies(filelist,**workinplace)

    # to keep track of the original file names we do the following trick:
    # pack filelist with the ivmlist using zip and later unpack the zipped list.
    #
    # NOTE: this required a small modification of the checkStisFiles function
    # in stsci.tools.check_files to be able to handle ivmlists that are tuples.
    if ivmlist is None:
        ivmlist = len(filelist)*[None]
    else:
        assert(len(filelist) == len(ivmlist)) #TODO: remove after debugging
    ivmlist = list(zip(ivmlist,filelist))

    # Check format of FITS files - convert Waiver/GEIS to MEF if necessary
    filelist, ivmlist = check_files.checkFITSFormat(filelist, ivmlist)

    # check for non-polynomial distortion correction
    if not updatewcs:
        # with updatewcs turned on, any problems will get resolved
        # so we do not need to be concerned about the state of the DGEOFILEs
        filelist = checkDGEOFile(filelist)

    # run all WCS updating
    updated_input = _process_input_wcs(filelist, wcskey, updatewcs)

    newfilelist, ivmlist = check_files.checkFiles(updated_input, ivmlist)

    if updatewcs:
        uw.updatewcs(','.join(set(newfilelist) - set(filelist)))

    if len(ivmlist) > 0:
        ivmlist, filelist = list(zip(*ivmlist))
    else:
        filelist = [] # insure that both filelist and ivmlist are defined as empty lists

    return newfilelist, ivmlist, output, oldasndict, filelist