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4.8 12845B Line Printer Interface with One 2607/13/17/18 Line Printer
The HP 12845B Line Printer Interface connects the HP 2607A (200 lines per minute), HP 2613 (300 lpm), HP 2617
(600 lpm), and HP 2618 (1250 lpm) line printers to the HP computer family. The simulation provides one printer
unit; the 2607 is selected by default. Attaching a text file to the unit simulates loading paper into the printer:
ATTACH {-N} LPT <image-filename>
Adding the
–N
(new file) switch clears the contents of the image file if present. Without the
–N
switch, printer output
will be appended to any preexisting image file content.
Printer output written to the image file is typically buffered by the host operating system’s underlying stream I/O
routines. While it is running, the simulator flushes the file after each printer top-of-form request to permit
convenient inspection of the image file. Stopping the simulator also flushes the file.
If the host operating system returns an error when writing to the printer image file, the simulator will report the error
to the simulation console, e.g.:
HP 2100 simulator printer I/O error: No space left on device
The printer goes offline with an alarm condition, and the simulator stops. Simulation may then be resumed, either
with the printer set back online if the problem is fixed, or with the printer remaining offline if the problem is
uncorrectable.
Detaching the text file from the unit with the
DETACH LPT
command simulates running out of paper. If the
command is entered while there are characters in the print buffer or, for the 2607 only, the print location is not at
the top of the form,
Command not completed
is displayed on the simulation console, and the file remains
attached until the required conditions are true. Once simulation is resumed and the print operations complete, the
printer is set offline and detached automatically.
Detaching may also be forced with the
DETACH –F LPT
command. This simulates physically removing the paper
and takes effect immediately, regardless of any printing operations in progress.
Device and unit options include configuring the printer type and timing, output format, vertical format unit (VFU),
and the ability to set the printer offline or online. The command forms are:
SET LPT <device-option>
SET LPT <unit-option>
