FUJITSU CentricStor V3.1D - Manual (Page 29)

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CentricStor - Virtual Tape Library Hardware architecture
2.2.1.3 IDP (Integrated Device Processor)
The IDP is the interface to the connected tape drives.
Figure 6: Internal and external IDP connections
The IDP is responsible for communication with real tape drives. To optimize performance,
only two real tape drives should be configured per IDP.
Because of the relatively short length of a SCSI cable (approx. 25 m), the CentricStor IDPs
are typically installed directly in the vicinity of the robot archive if a SCSI connection is to be
used to connect the drives.
It is capable of updating tape cartridges onto which data has already been written by
appending a further logical volume after the last one.
A cartridge filled in this way with a number of logical volumes is also referred to as a stacked
volume (see
section “Administering the tape cartridges” on page 35 ).
Communication with the other processors takes place over a LAN connection.
2.2.1.4 ICP_IDP or IUP (Integrated Universal Processor)
An ICP_IDP provides the features of a VLP, an ICP and an IDP. This processor has inter-
faces to the hosts and to the tape drives.
However, the performance is a great deal lower than if its functions are distributed on its
own processors of the types VLP, ICP and IDP.
IUP (Integrated Universal Processor) is a synonym for ICP_IDP.
FC
IDP
FC SCSI or FC
SCSI or FC
Robots
CentricStor
Robots CentricStor
LAN
Hosts
Interfaces
to the host Interfaces to
tape drives
FC FC
ICP_IDP