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From: rodgers@csc.wcc.govt.nz
Newsgroups: comp.lang.postscript
Subject: Re: PostScript Language
Message-ID: <1271.25eecdf8@csc.wcc.govt.nz>
Date: 2 Mar 90 07:48:08 GMT
References: <9447@imagen.UUCP> <38910@apple.Apple.COM> <147@heaven.woodside.ca.us> <18027@rpp386.cactus.org>
Organization: Wellington City Council
Lines: 43

In article <18027@rpp386.cactus.org>, woody@rpp386.cactus.org (Woodrow Baker) writes:
> In article <147@heaven.woodside.ca.us>, glenn@heaven.woodside.ca.us (Glenn Reid) writes:
>> No, I think PostScript succeeded mainly because it is ASCII.  People
>> can understand something that they can see.  People like that.  A lot
>
> Absolutely, but I think it should be full 8 bits...

Given that

a) ASCII is only a 7 bit code, and
b) some communication channels are only 7 bits wide,

it seems like a good idea from a device independence point of view to
restrict PostScript to 7 bits.  It stops people with 8 bits writing code
that is useless to people with only 7 bits.

The reason that most people complain is because most PostScript
images tend to be transmitted in hex resulting in twice as much data.
What people forget is that the format of the image is not defined by
PostScript.  It's just that because most people are too lazy to code
there own routine to read the data (readsevenbitstring??) and use
readhexstring that the image is so big.

We often see discussion in this newsgroup about the merits of
run length encoding for images.  Mostly the people who hae tried it
say that it doesn't gain you anything.  But on what processors?  On an
old 68000 based printer this is probably e true but what about the 68020
based printers?  What about the 68030 or 68040 or whatever else
printers that will probably come out in the future?  Printer
controllers are getting faster and faster while baud rates are
remaining constant so it won't be long before a PostScript printer can
print an image much faster than a HP-PCL printer.  Unless of course HP
come out with PCL level n (n > 5) that supports run length encoded
images.  But PostScript doesn't need any new features.  We can
implement whatever we like now.

The strength of PostScript and why I think it has caught on is
that it is a full computer language and we can do anything we like
with it.
--
Mark Rodgers                                          Computer Services Section
rodgers@wcc.govt.nz                                     Wellington City Council
Telephone (04) 733-130                    P.O.Box 2199, Wellington, New Zealand
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