[comp.lang.postscript] 7-bit or 8-bit ASCII for PostScript

zjat02@apctrc.trc.amoco.com (Jon A. Tankersley) (09/08/89)

Don't have the books with me here.....  Is PostScript supposed to be
7 bit ASCII or 8 bit?  I've been able to download IBM's DCF SCRIPT in
ASCII, but it is 8 bit.  Drives the lowly Apple LW crazy trying to print.
I can convert it to 7 bit, but I was wondering if it was defined in the
language anywhere.


-tank-
#include <std/disclaimer.h>		/* nobody knows the trouble I .... */
tank@apctrc.trc.amoco.com    ..!uunet!apctrc!tank

mic@ut-emx.UUCP (Mic Kaczmarczik) (09/10/89)

In article <1016@apctrc.UUCP> zjat02@apctrc.trc.amoco.com (Jon A. Tankersley) writes:
>
>Don't have the books with me here.....  Is PostScript supposed to be
>7 bit ASCII or 8 bit?  I've been able to download IBM's DCF SCRIPT in
>ASCII, but it is 8 bit.  Drives the lowly Apple LW crazy trying to print.
>I can convert it to 7 bit, but I was wondering if it was defined in the
>language anywhere.
>
>
>-tank-
>#include <std/disclaimer.h>		/* nobody knows the trouble I .... */
>tank@apctrc.trc.amoco.com    ..!uunet!apctrc!tank

As I understand it, the PostScript language only uses 7-bit printable
characters, specifically so 7-bit serial communications problems like
the one you're having won't occur.  The fact that most implementations
of PostScript are happy with 8-bit characters is more a feature of the
implementation than the language.  Too bad the person who wrote the
PostScript driver for SCRIPT apparently either didn't know about this
or didn't expect people to print SCRIPT PostScript output on anything
but IBM's PostScript printer. 

We had this very problem at my site about a year ago, and I cooked up
the following piece of code to set a LaserWriter's data channel to 8
bits and no parity instead of 7 bits and even parity.  The parameters
to setsccbatch are in the back of the Adobe red book (at least the
original one that I have).  Make sure the rest of your communications
path to the LaserWriter is running at 8 bits and no parity as well,
otherwise things could get worse instead of better! 

-----------------------------------CUT HERE------------------------------------
%!
% 8bit.ps
%
% Change the permanent batch mode parameters in statusdict, to use 9600
% baud, no parity, and an 8-bit data path.  You may have to change the
% password to make this really work, depending on how you have set up
% your LaserWriter.
%

serverdict begin 0 exitserver
statusdict begin
	25 9600 3 setsccbatch
end
-----------------------------------CUT HERE------------------------------------

Mic Kaczmarczik
-- 
Mic Kaczmarczik					   Internet: mic@emx.utexas.edu
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