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

Describing Asynchronous Devices
How Operation Modes Set Functionality
Chapter 9
164
Spooled Devices
MPE/iX is equipped with a spooling facility to assist in the management of nonshareable
devices. When a spooler process controls a nonshareable device, the device appears to be
shared among several users, when in fact, it can process only one file at a time. This is
done by temporarily storing data on disk instead of sending it directly to the device. The
disk essentially becomes a staging area, while the spooler manages the selection of
output spool files destined for the spooled device.
A user program writing data to a spooled output device actually writes records to a disk
file instead of to the device itself. When the output device is available, the spooler
process selects a file and begins to send the data in the file to the device.
Slaved Devices
If two devices share the same port in the DTC (one device is connected to the port and
the other device is connected by an additional cable to the first device), only one device is
recognized by the DTS software. The device that is recognized is referred to as the
master device, while the other device is called a slave device. The master might or
might not be the device that is physically connected to the port.
NOTE The existence of slaves is not known to the DTS software or the MPE/iX operating
system. Therefore, slaved devices are not supported.
A wide variety of devices can be connected as slaves, such as terminals, printers, card
readers, flexible-disk drives, cartridge tape units, and plotters. Slaves can be connected
in the following ways:
• As pass-through slaves (also called eavesdrop).
• As remote slaves (also called end-of-the-line).
UPS Devices on the DTC
Ports on the DTC can be configured to support UPS connections. When a DTC port is
configured and connected to a UPS, the port is able to receive status messages about the
condition of the UPS. These messages are passed on to the operating system and
displayed as console messages. When a DTC port is configured for a UPS connection, the
port cannot be used as a session-accepting device.
Configuration of DTC ports for UPS connections is similar to port configuration for
terminal connections. To configure a port for a UPS connection, a profile is needed which
is identical to TR10D96 except for the following parameters:
• Line speed is set to 1200.
• Allow :HELLO logon? field is set to N.
• First device class field is HPUPSDEV.
The sample configuration file, NMSAMP1.PUB.SYS, contains the profile UP10D12 which is
configured with the above parameters. Enter this profile in the Profile Name field on
the Async Card Configuration Screen for the DTC port corresponding to the UPS
connection.
For DTCs under PC-based management, you must configure the correct baud rate using
the OpenView DTC Manager.