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From: prc@erbe.se (Robert Claeson)
Newsgroups: comp.std.misc
Subject: Re: Int'l Character set (Was: Re: filen
Message-ID: <1680@hulda.erbe.se>
Date: 29 Jun 90 07:32:13 GMT
References: <10720@<1990Jun1> <17000002@WL9.Prime.COM> <1679@mountn.dec.com> <106@lysator.liu.se>
Organization: ERBE DATA AB, Jarfalla, Sweden
Lines: 34

In article <106@lysator.liu.se>, aronsson@lysator.liu.se (Lars Aronsson) writes:

> Now, ISO 8859 is intended for sequential transfer of readable text.

And so is ASCII (really).

> Unfortunately, Sun Microsystems (and probably others aswell) will soon
> (has already?) start to ship operating systems (SunOS 4.1), where ISO
> 8859 is used for internal storage, e.g. in text files. Under UNIX,
> most common text editors (like emacs) do not scan the entire file to
> be edited, but use random access.

I believe you've got it somewhat wrong here. ISO 8859 specifices a set of
character sets, divided into two 7-bit pages (of which the left page, ie
character codes 0-127) is the same thing as ASCII) for a total of 8 bits.

ISO 8859 specifies 65 control characters (the first 32 in each page plus
the last character in the left page). It does not, however, specify a
means for switching among various character sets. That is the intent of
ISO 2022. A data stream that is encoded using ISO 8859 can be accessed
in any random order. Each character has its distinct meaning. There are
no multi-byte sequences specified in ISO 8859, although they can be
constructed using sequences of control- and graphic characters (which is
what ISO 2022 uses).

However, any data stream that is encoding using a character set (including
the infamous 7-bit set ISO 646) and that uses ISO 2022 for switching
among various character sets, can only be accessed in sequential order.

-- 
Robert Claeson                  |Reasonable mailers: rclaeson@erbe.se
ERBE DATA AB                    |      Dumb mailers: rclaeson%erbe.se@sunet.se
                                |  Perverse mailers: rclaeson%erbe.se@encore.com
These opinions reflect my personal views and not those of my employer (ask him).