BASIC CONCEPTS
formats. Each set of unique definitions represents a job and is
called a JDE or a job.
A JDL (compiled JSL) file containing printing instructions for the
LPS is required to print any job on any configuration. Many
specialized functions can be accomplished with PDL statement
commands. Refer to the Xerox 4635 LPS PDL/DJDE Reference
for specifics.
Several basic JSL files are provided with the OSS; for example,
ENET.JSL is provided for printing Ethernet jobs, ONLINE.JSL is
provided for printing online jobs, a XEROX.JSL is provided for
printing magnetic tape jobs, and so on. To meet specific
application needs, any OSS-supplied JSL can be copied and
modified. All Xerox LPSs have as a standard feature the LPS
Editor utility for the creation and modification of program source
files (FSL and JSL extension files).
Fonts
A font is a character set which has a unique typestyle, type size,
and orientation. Both fixed and proportionally spaced fonts are
available for use on an LPS. Each font character occupies an area
called a character cell. All character cells in a fixed font are the
same width, while character cells in a proportional font vary in
width, as shown in figure 2-4.
Figure 2-4. Character spacing
Because the length of a line printed with a proportional font is
relatively unpredictable, fixed fonts are used for variable data on
a report to avoid overprinting of forms by variable data.
Proportional fonts are normally used for forms data, such as,
titles, headings, and so on. A business letter is an example of
the use of proportional fonts for variable data. The difference in
line length is illustrated in figure 2-5.
Figure 2-5. Character spacing examples
2-8 XEROX 4635 LASER PRINTING SYSTEM PRODUCT REFERENCE
