XML.com's XML Conformance Update shows Microsoft and Oracle's parsers to be significantly behind open source parsers in XML 1.0 conformance.

The testing, conducted by David Brownell, shows Sun's parser (recently contributed to the Apache project) and the Apache Xerces parser coming out top in the conformance stakes, closely followed by Ælfred 2 and James Clark's XP.

All four parsers are now under an open source license, although Sun and IBM made considerable efforts in XML conformance before opening the source. The gap between the top performers and the Microsoft and Oracle parsers was over 10% in terms of test pass-rate.

Brownell used versions of the original OASIS 1.0 test suite updated by himself to reflect the errata to the XML 1.0 specification issued by the W3C since the original tests last year. His tests are available for download (approx. 4MB in size!)