Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!hannah.dec.com!batcheldern
From: batcheldern@hannah.dec.com (Ned Batchelder, PostScript Eng.)
Newsgroups: comp.lang.postscript
Subject: Re: ^D's
Message-ID: <8905091312.AA22444@decwrl.dec.com>
Date: 9 May 89 13:12:25 GMT
Organization: Digital Equipment Corporation
Lines: 38

In article <8407@chinet.chi.il.us>, les@chinet.chi.il.us (Leslie Mikesell)
writes:
>How many places does something have to appear in an official reference
>manual to make it official.

My reason for excluding Appendix D was not that something has to be
repeated to be meant, but that Appendix D is not defining the PostScript
language.  The Red Book that has appendix D does more than define the
language, it also describes implementation details about a particular
printer (the Apple LaserWriter) that implements the language.  Not
everything that the LaserWriter does is part of PostScript.

>Perhaps we should have a separate discusssion about printers that emulate
>the apple laserwriter and stop talking about ^D and postscript.

Although one of the reasons for not putting ^D in a file is that some
printers don't understand it, it is not the main reason.  We could restrict
our discussion to LaserWriters only, and we would still get into problems
if ^D's are in the files.

The Unix spoolers that are looking for the ^D echo will still get
confused if it is a LaserWriter at the end of the wire. 

The main point to keep in mind is that the intention of the ^D was as an
end-of-file marker to be used by spoolers (or application back-ends if they
were spooling the file). They were never intended to be put into files.

If you are working in an environment which does not fully support the
PostScript model of printing, there are naturally many ways you could patch
things to get it to work for you.  But if you patch it in the wrong way, it
will work for ONLY you.  Putting ^D in files is the wrong patch.  The right
patch is to arrange that a ^D is sent to the printer after the file is sent. 

As a number of people have pointed out here, it isn't that difficult to get
a ^D to a printer in MS-DOS.  If you make the small effort required,
everything will work.

--Ned Batchelder, Digital Equipment Corp, BatchelderN@Hannah.DEC.com