HP StoreEver MSL6480 Tape Library User Manual
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Figure 17 Library configuration example
In this example, there are two physical tape drives in the library; each of these is shown under
“Tape drives” as “Hewlett Packard LTO Ultrium-6 drive.” At boot time, the drivers discovered eight
paths to supported SCSI devices in the system, although not all paths were in active use.
Each drive has an SSC device (i.e., tape drive) and an SMC device (i.e., media changer). Each
of those can potentially be accessed through either of the drive’s two primary ports, for a total of
two paths per drive and eight paths total (4 tape drive paths, two each on 2 drives, and 4 media
changer paths to one media changer).
The failover drivers have one path to each of the two tape drives through Switch A. The failover
drivers also have one path to each of the two tape drives through Switch B. Each of those four
paths can potentially connect to either the tape drive or the tape library. At boot time the drivers
discover a total of eight potential paths to devices.
This results in the Windows Device Manager view that is shown in
. The failover
paths appear under System devices. A virtual bus named AdvFO Tape Multi-Path Intermediate
Class Driver ROOT FDO is created to enumerate the multi-path capable devices. Each of the eight
paths appears as AdvFO Tape Multi-Path Intermediate Class Driver SCSI FDO.
The drivers make one path active to each tape drive and one path to the tape library active through
the drive hosting the active control paths. Each physical device appears once in the Device Manager.
Under Tape drives there are two instances of Hewlett Packard LTO Ultrium 6 drive and under
Medium Changer devices there is one instance of HP ESL G3 Tape Library.
NOTE:
A number of devices have been removed from this view to improve readability.
Windows driver theory of operation
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