Binary Data in XML : Turning back the clock

Joe Lapp jlapp at
Wed Sep 30 18:44:51 BST 1998

At 12:11 PM 9/30/98 -0400, Jonathan  A. Borden wrote:
>The problem with base64 encoding of binary data in and of itself is that it
>says NOTHING about the format of the data[...]

I suspect that this is a schema issue.  We already have this problem
with the following elements:

    <date>Sept 30 1998</date>

Seems to me that the base64 issue is orthogonal to the data type issue.
I can represent the same gif in three different base encodings.

Now the real purpose in defining the xml:package attribute (or whatever)
is to ensure that the binary data is the same binary data in both the
XML producer and the XML consumer.

I don't know whether anyone will do so, but one might argue that if we
don't nail the exact format (gif, jpeg, whatever), then there is no
point in having the encoding.  One might say that you still can't do
anything with it.

But the counter-argument is the same argument for why XML has value
despite the fact that it doesn't define the semantics of all tag names.
We can use XML as the transport format and move application-specific
synactic issues (date format, image format) and semantic issues (what
the tags mean) completely into the applications themselves.  Without
saying how one puts binary data in an XML document, we cannot markup
binary data and shuttle it around in a portable way.
Joe Lapp, Senior Engineer | jlapp at
webMethods, Inc.          | Voice: 703-267-1726 |   Fax: 703-352-0370

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