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Configuring Systems for Terminals, Printers, and Other Serial Devices: HP 3000 MPE/iX Computer Systems > Chapter 9 Describing Asynchronous Devices
How Operation Modes Set Functionality |
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Six device operation modes can be used. Each has different capabilities and is intended for a specific purpose. The six are as follows: On CIO systems, the system console is the only device that is not connected to the computer through a DTC. The computer is aware of its existence from system initialization. It is connected to a special interface card in the cabinet called the access port. Although the system console is session-accepting, it has the following added functionality:
Because the system console serves a specific purpose, the following functionality is not provided:
Some console functionality can be given to the logical console. The system console can "pass" console functionality (except [CTRL]-A) to any other user; a user with system manager capability can "grab" the console by issuing the CONSOLE command. The logical console can receive messages sent to the system console, but it cannot execute console commands that require the console attention character ([CTRL]-A). When a logical console is used, the system console can still execute [CTRL]-A commands. Refer to "Session-Accepting Devices" later in this chapter for more information on the logical console. The logical console cannot be assigned to:
HP Precision Bus (HP-PB) provides console support for some models of the HP 3000 Series 900 family. It is supported by the SCSI/Console LAN Card. This card provides two serial ports for remote and session activity. HP 3000 Series 9X8 systems have a third port available for a UPS device connection. The first two serial ports only support the 239X and 700/9X terminals and emulators with Terminal Type 10. They do not support the following:
In addition, the console port does not support:
The first serial port provides a connection to the local console. The port is always fixed as LDEV 20. For backwards compatibility with the CIO console, speed and parity on the console cannot be changed. The speed is set at 9600 baud and the parity is set at none. The second serial port is capable of connecting to the console port path and connecting directly to the system. Although the second port can connect directly to the system and be used as a user port, it should be reserved for remote support access. It is configured as LDEV 21 by default. Baud line rate is set at 9600 and parity is set at none.
The third port, on HP 3000 Series 9X8 systems only, can support an HP PowerTrust UPS connection. Refer to Chapter 5 “Configuring Serial Devices (for Host-Based Management)” and Chapter 6 “Configuring Serial Devices (for PC-Based Management)” for details on how to configure this connection for host-based and PC-based management environments, respectively. These devices are able to provide status information about the condition of the UPS to the system through this port. The system will respond and provide console messages to the operator regarding the status of the UPS. This port cannot be used for session access because the port is not configured as session-accepting. This port is configured in SYSGEN as ldev 22 by default; the baud rate is set at 1200 and the parity is set at none. For more information on the UPS, refer to Performing System Manager Tasks. Session-accepting devices are opened with the HELLO command, and then a session is initiated. The session remains active until the user logs off by typing the BYE command, or initiates a different session by typing the HELLO command. Session-accepting devices are terminals or PCs running in terminal emulation mode. During a session, the terminal is used for interactive (conversational) communication with the computer. The terminal user can do any of the following:
Also, session-accepting devices that are not connected through a PAD or Telnet/iX and are not configured for switching can temporarily obtain partial system console functionality by using the CONSOLE command. A terminal that is the logical console can receive console messages, execute commands that do not require [CTRL]-A, and return console control to the system console (through the CONSOLE command). Programmatic devices run under the control of a program on the computer. The program accesses the device through the file system by treating the device as a file (device file). The file system passes information from the controlling program to the software which communicates directly with the device. A programmatic device is captive of the program because access to the device is through the program only. For instance, MPE/iX commands cannot be executed from a terminal under the control of a program unless the controlling program initiates the command. A programmatic device can be used for input, output, or both, depending on the device and how the controlling program opened it. 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. 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.
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: 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:
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. For more information on the UPS, refer to Performing System Manager Tasks. |
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