Version 4.1.0 of the netCDF Operators (NCO) has been released. NCO is an Open Source package that consists of a dozen standalone, command-line programs that take netCDF files as input, then operate (e.g., derive new data, average, print, hyperslab, manipulate metadata) and output the results to screen or files in text, binary, or netCDF formats.
The NCO project is coordinated by Professor Charlie Zender of the Department of Earth System Science, University of California, Irvine. More information about the project, along with binary and source downloads, are available on the SourceForge project page.
From the release message:
This release implements NCO's first data security/integrity checks, consisting of MD5 hashes of data for each variable. These optional checks are available in ncks and ncrcat. Thanks to Patrick from IPSL for suggesting this.
A new "feature" of netCDF3 has been identified that can lead to unusually slow performance. Unfortunately, this problem is triggered by an aggregate pattern of file access so the workaround must be implemented in the application software (i.e., NCO) rather than in the netCDF library itself. It is normally encountered on Multi-record Multi-variable netCDF3 files (MM3s), so we call this the MM3-workaround. If you encounter unusually slow NCO performance while using NCO to analyze MM3 files on a large blocksize filesystem, chances are you are encountering an MM3-induced slowdown. This NCO release implements the MM3-workaround for ncks. It speeds-up common ncks sub-setting on NCAR's GLADE by 10-50x. MM3-induced slowdowns may be present in other NCO operators and we are prioritizing our MM3-patches to those encountered most often. Thanks to Gary Strand for reporting this problem, and to Russ Rew for creating the workaround algorithm, which is also now in nccopy. More on this story as it develops at http://nco.sf.net#bug_mm3.