Microsoft has responded to David Brownell's report on their Msxml.dll XML parser's conformance to the OASIS XML Conformance test suite.

Brownell's article, a followup to a previous article on XML.com that tested Java parsers, found that Msxml.dll, the COM version of Microsoft's parser, did much better than its now mostly-defunct Java partner. Msxml.dll ships with Internet Explorer, and a slightly revised version ships with Windows 2000 and Internet Explorer 5.01.

Microsoft acknowledged that some conformance failures, notably in character checking, were due to performance trade- offs, while claiming others were easily fixed by developers using the parser with a few lines of code. Microsoft's insistence on namespace support also cost it a few cases that were legitimate XML 1.0 but not acceptable in a namespace-aware environment.

Microsoft closed their conformance discussion by criticizing 17 of the tests, arguing that they were related to either namespace support or 'hotly contested differences of opinion about how to interpret the XML specification.'

Developers using the Msxml.dll parser can be reassured that it passed most of the tests, but may want to read both the original article and the Microsoft response to gauge interoperability if documents will be processed by multiple parsers.

Late updates:

• Steve Newcomb posted a message to XML-dev on interoperability issues and their importance.
• David Brownell posted a response to Microsoft's article on XML-dev with his initial reactions and a more detailed reply.