Printing Directly From a Mainframe Computer with LCDS
Line Conditioned Data Stream (LCDS) is a mainframe to printer, Page Description Language (PDL) which uses referenced (stored on the system) and datastream-embedded commands to control the processing of print jobs submitted from mainframe computers.
The Xerox LCDS approach to printing dramatically reduces bandwidth requirements by locating the final assembly of document elements on the printer where resources are stored. This eliminates the need for repeatedly sending complex elements like forms from the host as part of a fully formed data stream. It reduces the need for sending these high bandwidth items for each job by permanently placing them on the printer so they do not need to be sent for each job.
The system only needs to send the truly variable data to the printer. Even values that can be derived like the sum of a column of numbers can be computed on the printer so that data transfer is minimized. This capability is unique in the industry and shows one reason why the LCDS data stream is selected by customers that need to minimize data bandwidth requirements in complex distributed systems.
LCDS printers offer the ability to control the format of the final product, the printed page, from outside the application generating the variable data. This separation of function between the data generating application and the printer has always been a common practice in the high performance range of computer printers. The data may be in its proper position but post processing steps between the application and the printer produces the final page appearance. The simplest way to visualize this type of printing is to think of preprinted forms where the printer prints variable information into blank areas of the form.
Enabling LCDS Printing: Overview
To use LCDS printing, the Operator or System Administrator needs to make sure that the following conditions are met:
- files containing the appropriate processing commands (see the "forms" analogy above) have been loaded on the system
- supporting resources (such as forms and fonts) are installed on the system
- the correct license is installed on the system
- one specific queue has been created and dedicated on the system to process LCDS (streaming) jobs
The selection and setting of additional queue parameters, available under the various tabs of the Queue Properties... dialog, in association with the resources installed on the system under LCDS Resources, determines how LCDS jobs are processed at the printer.
For more information about queues, see Working With Queues.
Verifying the presence of the LCDS License
To print LCDS jobs, you must verify that the LCDS license is installed and enabled on the system.
Viewing LCDS Resources
To support LCDS, files containing the appropriate processing commands and supporting resources (such as forms and fonts) must be installed on the system under LCDS Resources. To view the currently-installed LCDS resources, perform the following steps:
- Log on to the system by selecting Logon… from the Logon menu.
- Select Operator (or System Administrator) as the user from the User drop-down list box.
- Enter the Operator (or System Administrator) password and click <OK>.
- Select [Administration: LCDS Resources].
- When the LCDS Resources window opens, if not already selected, select System from the Source drop-down menu.
- A list of installed LCDS Resources will be displayed. Note the resource types displayed under the Type category. FNT, for example, represents Font. FRM represents Form. JDL represents Job Descriptor Library (a source file of compiled PDL commands).
- To select the specific types of resources displayed in the LCDS Resources window, click the Types... button which opens the System Resource Types dialog. After selecting the desired resource types (by placing check marks in the boxes), click OK.
For further information about LCDS printing with the system, refer to the LCDS documentation provided with your system. See your System Administrator or Xerox Customer Representative to obtain this documentation.