Data Dictionary System: Users Runtime Control

The following Runtime Control parameters are available to control some runtime behaviors of DDS applications. The names can either be all upper case or all lower case.

• DATA_PATH defines the path used when creating default filenames for output binary data. When not provided the default path is the current working directory. Users may setup a default for output binary data to an alternate file system. It may provide high capacity, alternate charges, or special backups. DATA_PATH is retrieved from the extended Dictionaries. So it can be specified on the command line or par file and it will be used in subsequent processing as it remains in the Dictionary history. For example:

comment= default path for binary output data
DATA_PATH= /data/gpss83/data1/zrls13/work

• DATA_SUFFIX defines the suffix used when creating default filenames for output binary data. When not provided the default suffix is "_@". DATA_SUFFIX is retrieved from the extended Dictionaries. So it can be specified on the command line or par file and it will be used in subsequent processing as it remains in the Dictionary history. For example:

comment= suffix binary data filenames with ".bin"
DATA_SUFFIX= .bin

• PRINT_PATH is used to control the DDS printout file. If not specified, the printout file is written to the current working directory. It can be used to define the directory where the printout is to be created or the filename for the printout itself. If specified as "/dev/null no printout is generated and if it is defined PRINT_PATH is retrieved from the DDS base Dictionaries (par: env:) which include the command line, par file, and environment parameter Definitions in that order. For example:

comment= default path for print files
PRINT_PATH= /data/gpss83/data1/zrls13/work

• DDS_PATH defines a search path for special format, "format.fmt.dds", and mapping, "format.map.dds", Dictionaries used during execution. The Definition may specify multiple directories, delimited by white space. DDS_PATH is retrieved from the DDS base Dictionaries (par: env:) which include the command line, par file, and environment parameter Definitions in that order. For example:

comment= give precedence to WEBG defaults
DDS_PATH= /webg/dds ~/dds

• DDS_PATH3 is identical to DDS_PATH. It is preferred to use DDS_PATH.

• DDS_DEBUG controls debug printout information (see Debug Support for details). It is retrieved from the DDS base Dictionaries (par: env:) which include the command line, par file, and environment parameter Definitions in that order.

• DDS_DUMP is identical to DDS_DEBUG.

The following Runtime Control parameters are only provided through environmental variables. They must be all caps only. GIO is the buffered I/O package which is a part of DDS.

• DDS_START_CMD causes it's value to be inserted in front of the execution of the binary by the startup script.

• DDS_START_MPI causes it's value to be inserted in front of the mpirun call for the execution of the binary by the startup script.

• DDS_TIMESTAMP causes a "timestamp" to be put into the printout file. A value "< 0" is the default which does not provide a timestamp; a value of "0" will put a timestamp at the beginning of each line; a value "> 0" will print a separate timestamp line after every DDS_TIMESTAMP seconds.

• DDS_PREALLOC is a switch to turn on preallocation for output files. It is only available on altix systems. The default, "n" is to not preallocate the output. A value of "y" will preallocate output files on altix machines.

• DDS_MNT is a switch to specify an alternate mount point for externally mounted directories. If a file is requested with this prefix directory, then DDS will check to see if the file exists without the prefix. This allows faster access to locally mounted files. If a file does not exist, then DDS will try the same file with this mount prefix. The trailing "/" does not have to be specified. The current default is "/hpc/".

• GIO_TRACE turns on GIO tracing to the file named, "${GIO_TRACE}gio_trace.pid".

• GIO_VERBOSE turns on printing GIO verbose messages.

• GIO_BLKSIZE overrides the GIO Block Size. A value "< 0" will attempt to turn of buffering; a value "> 0" will use that value as the fixed I/O block size. The default is to allow GIO to adapt to an optimum value with a determined range.

• GIO_BUFMODE overrides the GIO buffer mode: "c" to use copy I/O; "m" to use memory mapped I/O; and "r" to use raw I/O.

• GIO_OPEN_MAX overrides the maximum number of open file descriptors that GIO uses. The default is to try and detect and adapt to what GIO determines is the correct value. If GIO runs out of file descriptors, it then temporarily closes some to manage many more virtual file descriptors with the limit real limit.