XimpleWare's VTD-XML is, far and away, the industry's most advanced and powerful XML processing model  for SOA and Cloud Computing!

• The world's most memory-efficient (1.3x~1.5x the size of an XML document) random-access XML parser. 
• The world's fastest XML parser: On a Core2 2.5Ghz Laptop, VTD-XML outperforms DOM parsers by 5x~12x, delivering 90~120 MB/sec per core sustained throughput.
• The world's fastest XPath 1.0 implementation.
• The world's most efficient XML indexer that seamlessly integrates with your XML applications.
• The world's only incremental-update capable XML parser capable of cutting, pasting, splitting and assembling XML documents with max efficiency.
• The world's only XML parser that allows you to use XPath to process 256 GB XML documents.
• The XML technology that they don't want you to know about.

  VTD-XML can be viewed a suite of innovative XML processing technologies centered around a non-extractive XML parsing technique called Virtual Token Descriptor (VTD). Depending on the perspective, VTD-XML can be viewed as one of the following:

• A "document-centric" XML parser
• A native XML indexer or a file format that uses binary data to enhance the text XML
• An incremental XML content modifier
• An XML slicer/splicer/assembler
• An XML editor/eraser
• A way to port XML processing on chip

Features are:

·        Conserving memory: (1)Because VTD records are not objects, it is not subject to per-object memory overhead. (2)VTD storage can be bulk-allocated (i.e., using large memory blocks): when allocating a large memory block to store 1024 VTD tokens, one only incurs the per-array memory overhead once, essentially reducing the per-record overhead to almost nothing.

·        High Performance: (1) Using VTD we attempt to achieve high performance in parsing, which is a by-product of VTD's memory conserving features: Less memory usage means less amount of memory is allocated. (2) Large memory blocks are faster to allocate and GC than many discrete objects. Please keep in mind that we are in the early stage of this technology. So further improvements on performance and usability should be expected.

·        Inherent Persistence: VTD records can be persisted on disk or transmitted along XML to improve XML processing throughput.

·        Incremental Update: This feature is well-explained in a recently article
http://www.xml.com/pub/a/2004/05/19/parsing.html

·        Cut, Paste, Split and Assemble

At the same time, one needs to be aware of the some of the limitations of VTD:

·        Upper limits of various fields: (1) For starting tags (the max Qname length is 2048; the prefix 512), overflow conditions result in parse exceptions. For other tokens (upper limit is 1M), one can potentially break a long token into multiple shorter ones.(2) Depth field overflow condition results in parse exceptions. (3) Starting offset: Currently the biggest document supported is 1G characters (1G bytes or 2G bytes, depending on actual document encoding).

·        Limit of Bit-level layout: It is possible that one needs to rearrange bit-level layout to meet actual processing requirement.

·        VTD Token length limit: Currently a VTD record is 64-bit in length. One can add another 32 bit if 64 bits are not enough.

·        Entity support: Current Implementation only supports built-in ones: &amps; > < ' "