Basic Information about Greek Alphabet
Greek alphabet is considered to be among the oldest on the planet. It has been used since approximately 800 BCE and is believed to be created as a similar one to the Phoenician alphabet, which is the oldest known writing system. Greek alphabet was also a revolutionary one since its system included distinctive letters for consonants and vowels. It is important also that the Greek alphabet is supposed to be the parental alphabet system for both Latin and Cyrillic alphabets, as well as Armenian, Gothic, Georgian, and other writing systems.
Modern Greek language includes 24 letters, 18 of which are consonants and 6 are vowels. There are also a few archaic letters which are used only in the language dialects, or have not been used for many centuries at all. As we all know very well, Greek alphabet is widely used in modern maths, geometry, astronomy, chemistry, science, etc. as the main language for symbols and technical labels.
Computer systems basically use two main encodings for Greek alphabet, which are Unicode (supporting polytonic and monotonic orthographies) and ISO/IEC 8859-7 (supporting only monotonic one). It is preferable to use Unicode both for temporary and old Greek letters, including a variety of really ancient systems for epigraphy. The most popular block of Unicode for Greek alphabet is Greek and Coptic, which is in the range of U+0370 - U+03FF. On the other hand, ISO/IEC 8859-7 system also follows a certain Unicode range (from U+037x to U+3CF).