Network Printing
In addition to remote spooling to a job file in another database, the Spooler supports remote spooling to a printer device on another host.
On a UNIX host, the printer connection can be across an Ethernet local area network (LAN) using TCP/IP or OSI protocols, or across an X.25 wide area network (WAN). Communication between the Reality environment and the remote printer device is enabled by UNIX-Connect software.
On a Windows host, the printer connection can be across an Ethernet local area network (LAN) using TCP/IP. The communication software is integral to Reality.
Printer Sharing
Printers can be shared between different host systems and Reality databases/applications on the network. Printer sharing capability is integral to Reality on Windows, but on UNIX uses a Network Printing Utility (npu) to drive the printer connection. In both cases, to configure the spooler for shared network printing, you must create a network printer definition item in the NETDEVS file - see Network Printer for details.
Note
If printer sharing is disabled, the network printer connection is permanent and solely under the control of the Reality Despooler, until the Despooler is re-configured.
Controlling Printer Sharing in Reality
Printer sharing can be enabled or disabled as required. Printer sharing is enabled and controlled at options 9, 10 and 11 on the DESPOOLER.CONTROL File Maintenance (DSM) menu.
With Printer sharing enabled (in DSM option 9), the Despooler holds on to the printer for a predefined period (specified by DSM option 10), after which it releases it for use by other Despoolers on the network. If the Despooler needs to despool a print job and does not have control of the printer, it tries to get control, if it fails, it goes to sleep and retries after a pre-defined period (specified by DSM option 11).
Printer Sharing using npu (UNIX only)
On UNIX, the npu, supplied with the UNIX-Connect software, allows its printer connection to be disconnected after a print job is despooled, so that other network users can use the printer. It then attempts to reconnect when it requires the printer again.
The following section describes the use of the npu printer sharing facilities by the Reality Spooler. For a complete description of the npu, including its operation and administration in the UNIX environment, refer to UNIX-Connect System Administration.
Configuring the Spooler with the npu
To use the Spooler with the npu, you must:
- Set up the network printer definition item in the NETDEVS file appropriately - see Network Printer for details.
- Set up the destination entry in /etc/ROUTE-FILE entry for npu operation - see The ROUTE-FILE.
- Include the location of npu (normally /usr/RCS/bin) in the PATH variable in /etc/realityrc.
Using an npu Private Printer Interface Script
A network printer can also be despooled by a PTR Despooler to an npu printer interface script, which then pipes the data to the npu. The npu interface script, supplied with the npu product, must be placed in an appropriate directory and its path name specified in DSM option 2, as for private printers.
When an npu private printer interface script is used, DSM options 9, 10 and 11 are not operative. The Despooler releases the network printer after each print job is despooled.