Ted writes:

> Wirt follows with a fascinating discourse on viewing postscript onscreen . .
>
>  With all due respect, sir, and with much interest in the subject you've
>  discussed, I think you missed the original comment (see above) which in
>  specific refers to putting ink on paper in a non-Postcript fashion.  Might
>  there be some appropriate way of doing so via the 3000.  After all, I for
> one
>  have quite a few non-postcript printers hooked to my 3000 and I'd like to
>  print out the pretty stuff QC produces on them, too.

Ultimately, PostScript graphical commands must be rendered (converted into a
bitmap) somewhere. The question is where?

If that rendering is done in the printer, where it should be, then the host
HP3000 only has to generate the simple, mathematically perfect graphical
commands that are characteristic of PostScript. An example of such code is
that necessary to draw a 100 point square, solidly filled with an orange
color:

     100 100 moveto
     100 200 lineto
     200 200 lineto
     200 100 lineto
     closepath
     0 50 100 0 setcmykcolor
     fill

Clearly, an HP3000 can produce a great deal of this sort of output at very
high speed. The receiving printer then renders these commands to best of its
ability, given whatever print capabilities it might have.

If, on the other hand, the design architecture chosen were to put the
rendering on the HP3000, just a very few users creating a few complex pages
could easily consume a moderate-sized HP3000. I would be pleased to state, as
a general law of the known universe, that graphical rendering should never be
done on a machine primarily dedicated to OLTP/OLAP transaction processing. To
do so imposes a substantial and wholly unnecessary burden on the host.

Beginning the LaserJet 4 series, however, PostScript upgrades have been
available for every HP LaserJet. The upgrades are nothing more than a SIMM and
they plug into a LaserJet with the same ease as a RAM upgrade does (indeed,
there is no outward difference in appearance between the two). Nor are they
expensive. They only cost a few hundred dollars per printer. Even more
surprisingly, for the LaserJet 4's and 5's, the upgrades cost less if you
purchase the LaserJets with the PostScript software factory installed; HP
charges you a 20% premium if you do the work yourself.

However, nowadays all of the new LaserJets (4000, 5000 & 8000) come with a
PostScript clone as a standard feature. It's no longer an option -- and I
believe that is the wave of the future. All laserjets, regardless of their
manufacturer, will have both PCL and PostScript as standard printing
languages.

A fairly informative set of technical descriptions on the new printers are
available on the web, in PDF format. One of these datasheets is:

        http://www.lj8000.hp.com/pdfs/lj8000.pdf

Wirt Atmar