🚀 go-pugleaf

jkimball@src.honeywell.com (John Kimball) writes:

[About problem with sending PostScript programs to other printers and
 the apparent lack of portability.]

jansteen@cwi.nl (Jan van der Steen) writes:

>There are two bottlenecks:

>	1. The PostScript code itself
>	2. The PostScript interpreter (executing the code)

[Detailed description of these two problems delete for brevity.]

I'd like to add two other frequently occurring problems:
	3. The PostScript file claims to be page independent and isn't.
	4. The page reverser doesn't properly handle the DSC comments.

First, a little background.  There is a Document Structuring Convention (DSC)
where comments are inserted into the PostScript file to tell where the prolog
and pages occur.  Version 1.0 of the DSC just indicated where the prolog,
pages and trailer occur.  Version 2.0 and 3.0 also handle the case where you
have nested documents.

3. One of the requirements of the DSC is that when you have delimited the
pages in the document, the pages must be independent of each other.  Meaning,
that you can send the prolog to the printer and then the pages in any order
and finally the trailer.  However, many programs that produce these comments
don't make sure that the pages are independent from each other.

4. Some PostScript printers stack the paper such that the first page printed
ends up on the bottom of the stack.  Many spooling systems recognize this fact
and have a page reverser to reverse the order of the pages.  However, if you
feed a document with version 2.0 or 3.0 DSC comments that includes a nested
document within it to a page reverser that only knows about the Version 1.0
convention, the page reverser is certain to scramble the document for you.

I believe that these two problem cause much more trouble than bad PostScript
implementations or bad PostScript code.  Fortunately, it is easy to avoid
these problems.  If the PostScript file does not begin with "%!PS-Adobe-n.n",
the page reverser will not touch it.  Simply change the first line from
"%!PS-Adobe-n.n" to "%!".

I find that this allows me to print many documents that failed the first time.
Unfortunately, I get to reverse the page order by hand :-(.

Hope this helps,  ...Tim

          Tim Theisen           Systems Programmer
Internet: tim@cs.wisc.edu       Department of Computer Sciences
    UUCP: uwvax!tim             University of Wisconsin-Madison
   Phone: (608)262-0438         1210 West Dayton Street
     FAX: (608)262-9777         Madison, WI   53706