Configuring Systems for Terminals, Printers, and Other Serial Devices (32022-90057)

Describing Asynchronous Devices
How MPE/iX Identifies Devices
Chapter 9
157
NOTE If two or more systems have access to the same nailed device, contention for that device
might exist. Only one system can access a nailed device at any time. For example, if
system A accesses the nailed device, system B will not be able to access the nailed device
at the same time. The nailed device is being used by system A and is probably not
broken, even though it can’t be reached.
An ldev number can be assigned to any asynchronous device, including the following:
• The system console
• Printers, Terminals, and Plotters
• Other serial devices
System Console
The system console is always connected through the access port on the HP 3000 Series
900 computer. The system console’s ldev number is assigned during system initialization
and remains constant unless it is modified through the SYSGEN utility and the host is
restarted.
Printer
Printers are assigned ldev numbers during configuration making them nailed devices.
Each printer keeps the same ldev number unless that number is modified through
NMMGR and the host is restarted.
Terminals
Usually, many terminals are connected to a DTC. Some terminals can have permanent
ldev numbers assigned during NMMGR configuration.
Other terminals might not have permanent ldev numbers assigned (non-nailed).
Instead, these terminals will use an ldev number from a pool of available ldev numbers.
Non-nailed devices can be configured if PC-based network management is used. Refer to
“Nailed Devices” and “Non-Nailed Devices” earlier in this chapter for more information.
Terminal users should know the physical device address for their terminal. If a terminal
is having problems, the physical device address is needed to troubleshoot the terminal.
The physical device address consists of identifiers for the DTC, the interface card, and
the port to which the device is connected. Refer to “Device Physical Path” later in this
chapter for more information.
Plotters
Sometimes plotters are connected to a DTC. Plotters, like printers, always have assigned
ldev numbers (always a nailed device).
UPSs
HP PowerTrust UPSs can be connected to DTCs as nailed devices. Only the MPE/iX
operating system accesses these devices.