User's Manual

DEC PDP-11 TAPES
15-4 XEROX LASER PRINTING SYSTEMS TAPE FORMATS MANUAL
Operating system operations
Within the Xerox Printing System Operating System, a record from
the PDP-11 FLX format is considered to be zero or more printable
characters followed by a single carriage-related control code. This
processing is important in relation to the Xerox Printing System
logical processing commands. It is also different from the way the
application program creates the records—as data followed by
multiple carriage codes.
FONTINDEX
To implement a FONTINDEX capability for this data extraction
process, the first parameter of the DATA= statement must be
interpreted differently from other tape formats. Normally, the first
parameter is an offset to the first byte of the record that is selected
for printing. Since multiple lines may result from what might otherwise
appear to be a single data line (as a function of the relation between
the second parameter of the DATA= and the length of the record), the
bytes that are “skipped” at the beginning of the record are saved and
used to provide the font selection control for the following lines, if any.
In basic function the FONTINDEX processing is no different from that
used in any other data extraction; however, the byte used for
specifying the font may apply to several lines instead of just one print
line.
Control codes
The individual control codes are defined in table 15-3. The codes
define skips to defined channels 1-7. These channels are normally
set to the following sets of line numbers to emulate a standard PDP-
11 carriage tape. (These assignments must be included in the Job
Descriptor Entry used to print the tape.)
Table 15-2. DEC PDP-11 suggested channel assignments
Channel Set of line numbers Purpose
1 1 (T-O-F)
2 1, 31 (1/2 page)
3 1, 3, 5..., 59 (every other line)
4 1, 4, 7..., 58 (every third line)
5 1, 2, 3..., 65 (every line without regard for
TOF or BOF)
6 1, 11, 21..., 51 (every ten lines)
7 1, 21, 41 (1/3 of a page)