Appendix D. OCP Information
87
OCP Architecture
Command Conflicts
Any operational conflict between commands received over SCSI or from the RLC and
those entered through the front panel are avoided with a reservation mechanism on a
first-come, first-served basis. Any reservation by the OCP is canceled by an OCP logout
or time-out, which cancels the user mode.
The library does not allow impossible requests. These include moving a cartridge from
any source to a full slot, moving a cartridge from an empty slot, loading a cartridge
from any source to a full drive, or unloading a cartridge from an empty drive.
Errors
If an error detected by the library or drive controller through predetermined firmware
algorithms is unrecoverable, a numeric error code displays on the OCP and the error
LED lights. The error code remains on the display panel until a push button is pressed,
which will cause the OCP to return to the Home Screen.
Numeric error codes are only used for unrecoverable errors; otherwise text status
messages are displayed.
Input Modes
You can specify information through the OCP by using the navigation buttons to
selecting one of several choices, toggle values, or enter numerical values.
Selecting One of Several Choices
After navigating to the menu item, the user selects the predefined value.
Toggling Values
Toggling values let you switch between two different states—for example, switching
between enabling and disabling a feature.
Entering Numerical Values
Users can enter numerical values to specify network addresses, PINs, and more.
