Chapter 14.   User Interfaces
This chapter configuration information for the user interfaces provided with  HPSS for transferring files:
•Client Application Programming Interface (API)
•Parallel File Transfer Protocol (FTP) or PFTP
•HPSS Virtual File System (VFS) Interface
14.1.  Client API Configuration  The following environment variables can be used to define the Client API configuration. The  defaults for 
these variables are defined in the hpss_env_defs.h file. 
HPSS_API_AUTHN_MECH specifies which authentication mechanism may be used.  The values may 
be “krb5” or “unix”.  The default is HPSS_CLIENT_AUTHN_MECH.
HPSS_API_BUSY_DELAY specifies the number of seconds to delay between retry attempts. Note  that 
this value is used both for retrying initialization operations (see HPSS_API_RETRIES) and Core  Server 
requests (See HPSS_API_BUSY_RETRIES). The default value is 15.
HPSS_API_BUSY_RETRIES specifies the number of retries to be performed when a request  fails 
because the Core Server does not currently have an available thread to handle that reque st. A value of 
zero indicates that no retries are to be performed (i.e., the operation will  be performed once), and a value 
of -1 indicates that retries should be attempted until either the request  succeeds or fails for another 
reason. The default value is 3 (which will result in up to 4 attempts). 
HPSS_API_DEBUG specifies whether to produce debug messages. If the Client API is compiled with 
debugging enabled, any non-zero value in HPSS_API_DEBUG enables debug messages. Note that non-
numeric strings will be interpreted as zero. By default, these messages will go to the standard  output 
stream (but see HPSS_API_DEBUG_PATH).
HPSS_API_DEBUG_PATH specifies the destination of debug messages; default is “stdout ”. If 
HPSS_API_DEBUG_PATH is set to "stdout" or "stderr", debug messages will be written to the standard  
output or standard error I/O streams, respectively. Otherwise, the value will be interpreted  as the 
pathname of a file. The Client API must be compiled with debugging enabled.
HPSS_API_DESC_NAME specifies the descriptive name used in HPSS log messages if the logging 
feature of the Client API is enabled. The default value is “Client Applicati on”.
HPSS_API_DISABLE_CROSS_REALM specifies cross-realm authentication. When cross-realm 
authentication  is disabled, a client will not be allowed to access  directories which are located in another 
security realm. The default value is zero (meaning that cross-cell authentication is e nabled). To disable 
cross realm authentication, HPSS_API_DISABLE_CROSS_REALM must be set to a numeric, non-zero 
value.
HPSS_API_DISABLE_JUNCTIONS specifies whether junction traversal is enabled. When  junction 
traversal is disabled, a client will not be allowed to access director ies which require traversal to the 
directory via a junction. The default value is zero (meaning junction traversal  is enabled). To disable 
junction traversal, HPSS_API_DISABLE_JUNCTIONS must be set to a numeric, non-zero value.
HPSS_API_DMAP_WRITE_UPDATES specifies the frequency of cache invalidates that a re issued to 
the DMAPI file system while writing to a file that is mirror in HPSS. The value indicates the  number of 
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