FUNCTION: root_data_dir PURPOSE: Returns the root data directory used by numerous file retrieval procedures. By default it returns either: for unix: '/disks/data/' if it exists, '~/data/' otherwise for Windows: 'c:/data/' if it exists; else 'e:/data/' if it exists, else 'c:/data/' regardless. These data sets can grow to very large size. These defaults are intended to allow multiple users to share a common data directory system. It is recommended that PC users create a separate partition (e:/data/) to store files so that disk backups do not have to include these large (easily replaced) files. On unix systems, it is recommended to create a common directory with global write permission that multiple users can share. This will reduce internet traffic and disk storage requirements for users that use common data files. CHANGING THE DEFAULT: The default directory can be changed by creating an environment variable: 'ROOT_DATA_DIR' Example 1: setenv,'ROOT_DATA_DIR=/mydata/' Example 2: A temporary directory: setenv,'ROOT_DATA_DIR=' + getenv('IDL_TMPDIR') + 'data/' ; trailing '/' IS required. If the value of the environment variable ROOT_DATA_DIR is a list of directories, then the first existing directory is returned. Notes: 1) The environment variable should be set prior to running initialization routines (put it in your IDL_STARTUP file) 2) The trailing '/' is required! PC users should also use '/' (not backslash: '\') 3) The total size of all files can grow immense and there is no need to back them up. We suggest placing them on a partition that is not backed up 4) File storage space can be shared with other users if a commonly accessible data directory is chosen. 5) Use a temporary directory if you do not want to permanently store these cached files. 6) The root data directory should be writable by all. This routine is called by: wind_init istp_init stereo_init lanl_spa_load thm_config (through thm_init) $LastChangedBy: davin-mac $ $LastChangedDate: 2014-11-23 08:38:23 -0800 (Sun, 23 Nov 2014) $ $LastChangedRevision: 16274 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/trunk/general/misc/root_data_dir.pro $