nASCII (ISO 646) solved a
fundamental interchange problem for flat text documents
äWhat bits encode what characters
–(For a pretty parochial definition of 'character')
nUNICODE/ISO 10646 extends
that solution to the whole world
nXML thought it was doing
the same for simple tree-structured documents
äThe emphasis in the XML
design was on simplifying SGML to move it to the Web
äXML didn't touch SGML's architectural vision
–flexible linearisation/transfer syntax
–for tree-structured documents with internal links
