An archive is a file that contains a collection of files and their metadata. In the context of TCGA, archives are the primary unit by which information is bundled: they are created and submitted to the DCC by data submission centers and made available for download via the TCGA Data Portal. Files are archived using tar and compressed with gzip and so they have the file extension .tar.gz. There are three types of TCGA archives: Data Archives, MAGE-TAB Archives and Auxiliary Archives.
The Mac tar command
The native tar command on Macintosh computers produces invalid archives. Users who are creating archives on a Mac must use the gnutar command instead.