The storage management software for the KEK central computer system is a customized version of HP OmniStorage. The HSM migration function is built into the DCE/DFS file server. Detail of the HSM and DCE/DFS implementation is provided in a separate report[2].
Figure:
Tape stacks in a single PetaSite tape library are divided into two
logical groups: (1) direct access stack, and (2) HSM stack.
Tapes in both stacks can be accessed from any CPU within the same
cluster.
We have also developed C and Fortran API functions to access
tapes directly (Fig. 
). Each tape handling transaction
is carried over TCP/IP sockets. A tape drive in the library can be
connected to any workstation in the same cluster as the tape library
server. Thus we have been able to build a parallel I/O system at a user
process level.