computer science

Western Latin character sets

Western Latin character sets is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Western Latin character sets rather than just read about it. In short: Several 8-bit character sets (encodings) were designed for binary representation of common Western European languages (Italian, Spanish, Portuguese, French, German, Dutch, English, Danish, Swedish, Norwegian, and Icelandic), which use the Latin alphabet, a few additional letters and ones with precomposed diacritics, some punctuation, and various symbols (including some Greek letters). These character sets also happe…

Key takeaways

Western Latin character sets belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Western Latin character sets to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Western Latin character sets from memory before moving on to harder problems.

Reference excerpt

Several 8-bit character sets (encodings) were designed for binary representation of common Western European languages (Italian, Spanish, Portuguese, French, German, Dutch, English, Danish, Swedish, Norwegian, and Icelandic), which use the Latin alphabet, a few additional letters and ones with precomposed diacritics, some punctuation, and various symbols (including some Greek letters). These character sets also happen to support many other languages such as Malay, Swahili, and Classical Latin. This material is technically obsolete, having been functionally replaced by Unicode. However it continues to have historical interest.

Summary The ISO-8859 series of 8-bit character sets encodes all Latin character sets used in Europe, albeit that the same code points have multiple uses that caused some difficulty (including mojibake, or garbled characters, and communication issues). The arrival of Unicode, with a unique code point for every glyph, resolved these issues.

ISO/IEC 8859-1 or Latin-1 is the most used and also defines the first 256 codepoints in Unicode. ISO/IEC 8859-15 modifies ISO-8859-1 to fully support Estonian, Finnish and French and add the euro sign. Windows-1252 is a superset of ISO-8859-1 that includes the printable characters from ISO/IEC 8859-15 and popular punctuation such as curved quotation marks (also known as smart quotes, such as in Microsoft Word settings and similar programs). It is common that web page tools for Windows use Windows-1252 but label the web page as using ISO-8859-1, this has been addressed in HTML5, which mandates that pages labeled as ISO-8859-1 must be interpreted as Windows-1252. IBM CP437, being intended for English only, has very little in the way of accented letters (particularly uppercase) but has far more graphics characters than the other IBM code pages listed here and also some mathematical and Greek characters that are useful as technical symbols. IBM CP850 has all the printable characters that ISO-8859-1 has (albeit arranged differently) and still manages to have enough graphics characters to build a usable text-mode user interface. IBM CP858 differs from CP850 only by one character — a dotless i (ı), rarely used outside Turkey and with no uppercase equivalent provided, was replaced by euro currency sign (€). IBM CP859 contains all the printable characters that ISO/IEC 8859-15 has, so unlike CP850 it supports the euro sign, Estonian, Finnish and French. IBM code pages 037, 500, and 1047 are EBCDIC encodings that include all of the ISO-8859-1 characters. The Mac OS Roman character set (often referred to as MacRoman and known by the IANA as simply MACINTOSH) has most, but not all, of the same characters as ISO/IEC 8859-1 but in a very different arrangement; and it also adds many technical and mathematical characters (though it lacks the important multiplication sign, ×) and more diacritics. Older Macintosh web browsers were known to munge the few characters that were in ISO/IEC 8859-1 but not their native Macintosh character set when editing text from Web sites. Conversely, in Web material prepared on an older Macintosh, many characters were displayed incorrectly when read by other operating systems. The Macintosh Latin encoding, a modification of Mac OS Roman to support ISO/IEC 8859-1, was created by the creators of Kermit (protocol) to solve this problem.

History

The earlier seven-bit U.S. American Standard Code for Information Interchange ('ASCII') encoding has characters sufficient to properly represent only a few languages such as English, Latin, Malay and Swahili. It is missing some letters and letter-diacritic combinations used in other Latin-alphabet languages. However, since there was no other choice on most US-supplied computer platforms, use of ASCII was unavoidable except where there was a strong national computing industry. There was the ISO 646 group of encodings which replaced some of the symbols in ASCII with local characters, but space was very limited, and some of the symbols replaced were quite common in things like programming languages. Most computers internally used eight-bit bytes but communication (seen as inherently unreliable) used seven data bits plus one parity bit. In time, it became common to use all eight bits for data, creating space for another 128 characters. In the early days most of these were system specific, but gradually the ISO/IEC 8859 standards emerged to provide some cross-platform similarity to enable information interchange. Towards the end of the 20th century, as storage and memory costs fell, the issues associated with multiple meanings of a given eight-bit code (there are seven ISO-Latin code sets alone) have ceased to be justified. All major operating systems have moved to Unicode as their main internal representation. However, as Windows did not support the UTF-8 method of encoding Unicode (preferring UTF-16), many applications continued to be restricted to these legacy character sets.

The euro sign The introduction of the euro and its associated euro sign (€) introduced significant pressure on computer systems developers to support this new symbol, and most 8-bit character sets had to be adapted in some way.

Apple with MacRoman and Sun Microsystems with Solaris OS simply replaced the generic currency sign (¤). This caused difficulty in some places because organisations had found other uses for its code point, such as the company logo. ISO introduced a further variant of ISO 8859, ISO 8859-15, which replaced the generic currency sign with the euro sign as well as making some other replacements of symbols with letters with diacritics. ISO 8859-15 never received widespread adoption. With Windows-1252, Microsoft placed the euro sign in a gap (position 80hex) in the existing C1 control codes, a decision that other vendors considered counter-architectural. Whilst these decisions had limited effect for documents that were only used within a single computer (or at least within a single vendor's "digital ecosystem"), it meant that documents containing a euro sign would fail to render as expected when interchanged between ecosystems. All of these issues have been resolved as operating systems have been upgraded to support Unicode as standard, which encodes the euro sign at U+20AC (decimal 8364).

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Western Latin character sets

Start with the simplest possible case. Write down what Western Latin character sets claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Western Latin character sets before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Western Latin character sets ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Western Latin character sets

In research: Western Latin character sets appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Western Latin character sets in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Western Latin character sets is common in secondary-school and first-year university syllabi. It links to neighbouring topics Articles with unsupported Private Use Area characters, Character sets, History of computing, so understanding it makes those chapters shorter.
In everyday life: Look for Western Latin character sets outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Western Latin character sets in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Western Latin character sets means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Western Latin character sets out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Western Latin character sets in simple terms?

Why does Western Latin character sets matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Western Latin character sets?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Western Latin character sets.