The indexing for SNIO and SMETIO was not working (because of BUFF_READ_BEFORE, we are almost never restarting exactly at the last read time step, but before). Moreover, SNIO was always reading the whole file, even past the specified dateEnd. This was extremely slow on large input file. This has been fixed. SNIO is still quite slow (it seems something like 10x compared to SMETIO), but it is much more acceptable. A file indexer class has been implemented in IOUtils.