HSI is intended to provide a simple-to-use command line interface to the High Performance Storage System (HPSS). It has evolved over the years from a simple 

HPSS Client API application that only ran on DCE/Encina-based AIX platforms to its current version, which uses its own own libraries and a client-server architecture to

provide HPSS access from almost all current Un*x-based systems, including Cygwin running on Windows-based platforms.

HSI was designed primarily as an alternative to the original PFTP that was part of the

HPSS offering.   It provides a number of features that are useful both to the user community and to HPSS system administrators, such as wildcard pattern matching, recursion for most commands, the ability to connect to multiple HPSS systems in a single HSI session and move files between systems using 3rd party copy protocols, and automatic optimization of tape mounts for operations such as "change COS" and "get".

Since different sites have different authentication requirements, HSI supports several different methods for verifying the end user's identity.  The HPSS site administrator can choose at compile time which authentication method(s) should be enabled.  The administrator also chooses a "default" mechanism to use - users can override the default authentication method at run time via a command line option ("-A"), or by specifying the method in their private $HOME/.hsirc file. Only authentication mechanisms that are supported on both the client and server can be used.

HSI uses strong encryption provided by the OpenSSL libraries for passing sensitive information, such as passwords, across the network. 

File transfers automatically make use of HPSS parallel file transfers without requiring any special action on the user's part.  Configuration files allow HPSS site administrators to tune network settings, specify a list of local network interfaces to be used on particular hosts, and to specify a restricted port range for sites that use firewalls in

front of client hosts.  HSI also supports a "firewall" mode for sites that cannot open a port range, which allows HSI to transfer data to HPSS via a store-and-forward mechanism to the HSI Gateway Server.

For sites that have a requirement for high-speed parallel transfers between cluster filesystems such as IBM's GPFS and Lustre, HSI supports the use of the multinode Transfer Agent.   By using the Transfer Agent, HSI file transfers are not restricted to rates that can be achieved by a single node, but can scale up by using multiple nodes.

Rates of over 2 GB/second from HPSS have been demonstrated using HSI with the Transfer Agent.

HSI continues to evolve to support new HPSS features and to accomodate the diverse needs of the user community. A wishlist of features that have been requested by the user community is maintained, and features are implemented as time permits.  Suggestions from the HSI user community for new features or enhancements of existing features are always welcomed.