[comp.laser-printers] IBM 4019 Emulation Switching

SMITHM@QUCDN.QUEENSU.CA (08/12/90)

About a week ago I posted an article in comp.lang.postscript complaining
that I was having trouble mixing PCL and PostScript documents on an IBM
4019 LaserPrinter.  Much of my complaint had to do with the inability of
IBM's PS2 Support Group to answer my questions.  The current article is
not an IBM bash.  It is directed to anyone who is considering buying
the 4019 with the intent of mixing emulations.  Since it took me quite a
while to find this information I hope I may save someone else in a similar
position a little trouble.

Here's the situation.  The IBM 4019 LaserPrinter supports a number of
emulations including PCL.  IBM also sells an inexpensive Adobe PostScript
option.  And, the story goes that you can select the desired emulation
with a software escape sequence.  Based on all this, the 4019 looked like
a pretty good choice for a mixed PCL/PostScript environment.

The bad news is described in IBM Manual S544-4265-00 "PostScript Option
for the IBM LaserPrinter Technical Reference".  Page 4-17 lists a
number of limitations on emulation mode switching.  The manual lists 6
but there are two that make the 4019 a *poor* choice for a mixed PCL/PS
environment:

1. When switching out of PostScript mode, the new emulation mode
   is *always* saved in NVRAM.  --> Each location in NVRAM is capable
   of approximately 6000 writes.

2. Data can be lost if it arrives too soon after switching modes.

I've asked repeatedly but cannot discover the procedure or cost of
replacing NVRAM.  And we did experience intermittent job failure
presumably because of lost data.  The manual isn't much help here.
Their advice: "[Data loss] is eliminated if the new data is not
transmitted until after the mode switch in the printer has
completed."

The bottom line for Queen's University is that we cannot recommend
the 4019 for mixed PCL/PS environments.  As for the poor bugger who
bought the 4019 thinking he could mix emulations, he has now decided
to use the 4019 as a PS printer only and convert his PCL applications to
PostScript.

 Mike Smith                                  SMITHM@QUCDN.BITNET
 Queen's University                          Michael.D.Smith@QueensU.CA
 Computing and Communications Services       (613) 545-2024