Frank Nagy writes:
 
>Ken Sletten rejoined:
>>  Also note that QueryCalc will do very efficient color Postscript output
>>  directly from the 3000 to the Postscript output device of your choice.
>>  Sorry HP, but Postscript is the way to go on this stuff.  We have one of
>>  the new Xerox 4900 Color Laser Printers on order;  it will go on the
>>  net for use with QueryCalc plus share with PC and Mac direct output.
>
>Sorry to say but with my demo copy I had problems with the printing of the
>bar charts. I tried them on our HP 2562C, on an Epson FX1050, and on a
Laserjet
>II P printer. Some features seen on the screen were missing - either the
values
>of the X axis or the shadowing - if I could have combined the printouts of
the
>three printers then I would have got a perfect graph.
 
I'm not sure what the specific cause of your printing problems were, Frank,
nor am I even sure that all of the printers mentioned are even HP
PCL-compatible, but your comments do precisely reflect the reasons we finally
abandoned all PCL support in 1992 -- old code which you were apparently able
to find, and which has now been completely scrubbed out of QueryCalc.
 
Switching to PostScript was a decision we finally made in 1991, but it was
also something we had been wanting to do since 1984. We stayed with PCL,
perhaps far longer than we should have, so long as HP had no PostScript
alternatives for its printers. HP3000 customers are generally quite pleased
with HP and are highly predisposed to want to continue to buy HP equipment,
thus we felt it necessary to support PCL. In retrospect, it was probably a
significant mistake that we stayed with PCL for as long as we did.
 
Support of PostScript has been an absolute joy. It is a rigorous standard
(because it is totally proprietary), it allows graphics of extraordinary
quality, clarity, and speed, it is exceptionally dense as a language, thus it
transmits over slow serial lines with great efficiency, and because it can be
written to be wholly restricted to the printable character set, it can be
transmitted through any combination of lans, repeaters, modems, and terminals
without effect or corruption.
 
But most importantly, it not only completely removes all graphics load off of
the HP3000 (the time to compose a page of exceedingly complex graphics and
text consumes less than a 0.1 seconds of CPU time), it is an absolute
standard that removes all device-dependent coding from the construction of
the software resident on the HP3000. What's transmitted in PostScript is not
a bit map but rather a mathematically perfect description of the object to be
drawn; the individual PostScript printer renders the output at whatever
quality it is capable.
 
What this means is that you can uplug an old 300dpi PostScript printer and
plug in a new 600dpi laser printer -- with absoultely no configuration
changes on the HP3000 or software driver changes in the applications code --
and the image instantaneously is made 4x better. And you then can unplug the
600dpi printer and plug in a 1200dpi printer, and again, instantaneously the
image is rendered 4x better again. The HP3000 is working no harder in any of
these cases; the image simply gets better with each increase in printer
capability.
 
This inherent device-independence allows for extremely rapid printer
evolution. Lexmark, just this month, released a new 1200dpi, 12ppm printer
retailing for approx. $1300. And color printers are evolving even more
quickly. 3-4 ppm color laser printers of excellent quality are now down in
the $8-9,000 range.
 
Color, which is very difficult to handle in PCL, adds no overhead at all to
the HP3000 in PostScript. The files are exactly the same size and require
exactly the same time to download (just a few seconds). And what happens if
you mix the printers? If you transmit a B&W file to a color printer, it
prints in B&W. If you transmit a color file to a B&W printer, PostScript
Level 2 automatically converts the file to the proper shades of gray.
 
Wirt Atmar