In-Line Resources

Control-D in-line resources can improve PSF performance. The performance improvement depends on the variety of PAGEDEFs and FORMDEFs that are used by your data center’s output. PSF holds in its memory up to seven copies of the most previously used PAGEDEFs and up to seven copies of the most recently used FORMDEFs. PAGEDEFs and FORMDEFs are used only by PSF and are not loaded to the printer. PAGEDEFs and FORMDEFs are instructions to PSF on how to format the output. PSF formats the output and sends it to the printer formatted, using IPDS (Intelligent Printer Data Stream). IPDS is the data stream that is used by PSF to communicate with the printer. It is a two way communication. Fonts, overlays and Page Segments (images) are downloaded to the printer. The more resident fonts, the better the performance. Page Segments can be included in an output by an overlay or by specifying an IPS structured field. When using the IPS structured field, you can optionally specify the Page Segment in the Page Segment list of the PAGEDEF. This is the suggested method for performance reasons, but it is not a requirement.

Using the Control-D in-line resource option, printer performance may be improved when using more than seven PAGEDEFs or seven FORMDEFs. This is because Control-D relieves PSF from reading the PAGEDEFs and the FORMDEFs from an external library at the time when the output is already selected to print from spool. Control-D reads the PAGEDEFs and the FORMDEFs from the external libraries in advance, immediately before sending the output to spool.