"Ingemar Olson" bio2935c@hotmail.com asks:

I would like to start proofreading but I'm stuck on the difference between ASCII and ISO 8859-1. For example, I am used to keying <alt-148> to write an ö, but the instructions ("Olika streck och andra specialtecken" på //runeberg.org/wiki/Instruktioner_för_korrekturläsare) state clearly to NOT use this technique.

As you say 'alt-148', the difference you are worried about is really the one between ISO 8859-1 and the character code used by your Windows system -- which probably is CP1252, which is just a superset of 8859-1. (ASCII is, as far as I understand, a 7-bit character set, related to the 7-bit ISO 646 character sets).

The difference between the two, however, is not in the 0xCO - 0xFF area, where most of the accented letters have been placed. But if you try to produce S/s or Z/z with caron, the OE/oe ligature, and y with diaeresis, and the various left and right single and double quotation marks, the different dashes, and several other special characters in the 0x80-0x9F area, it won't work.

That is, in principle, the alt-xxx method won't work, as it produces characters in a different character set. However, if you know the difference between the two character sets, you can get by. The risk for making errors can be high, especially if you acquire bad keyboarding habits, and there are no safety nets.

For a full description of the differences, see

http://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WINDOWS/CP1252.TXT

Any character with the same CP1252 and Unicode code point is safe:

0xC5 0x00C5 #LATIN CAPITAL LETTER A WITH RING ABOVE

If the differ, you have to use another method:

0x8E 0x017D #LATIN CAPITAL LETTER Z WITH CARON

Strictly speaking, this describes the mapping from CP1252 to Unicode, but as the first 256 code points of Unicode are the same as those of ISO 8859-1 (a 8859-1 to Unicode mapping table can be found under .../MAPPINGS) the difference is only superficial.

In the same catalogue (.../WINDOWS/) other code mapping tables can be found.

So I'm confused. How DO I make sure I generate the ISO characters?

I'm sorry -- I'm not much of a Win expert.

I would use a Wordpad, Save as 'ANSI', and then use the GNU recode program myself (under Cygwin -- assuming it can be compiled). I better leave it to any Windows expert to say if the same effect can be produced with pure Win tools.

I've been told that there are two forms of the ALT- keyboarding method: the ALT-xxx method and the ALT-0xxx method, and that the difference can be useful when you know exactly how they work. There seems to be one or two web sites describing it (search for ALT-0xxx): you might want to investigate. Personally, I regard ALT- as unfit for human use.

best wishes,