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 These days, I mostly post my tech musings on Linkedin.  https://www.linkedin.com/in/seanmcgrath/

Saturday, July 24, 2004

square roots ahead - the relationships between paper sizes

Markus Kuhn has a fascinating web page about international standard paper sizes and provides the magic numbers you need if your photocopier is ISO challenged. e.g. A3 -> A4 = 71%.

It is also riddled with many "not many people know that" type factoids. Did you know for example, that in Germany many brands of toilet paper are ISO A6 format.

Now *that* is attention to detail.

Friday, July 23, 2004

xerces command line utility

It has taken me an hour to figure this out, so I might save you some time.

If you want to use xerces-j to validate an XML instance against an XSD schema that is specified on the command line (as opposed to using schemaLocation attribute), do this:

java dom.ASBuilder -a foo.xsd -i foo.xml

The FAQ for Using XML Schemas on the apache website says (my italics):

"Each document that uses XML Schema grammars *must* specify the location of the grammars it uses by using an xsi:schemaLocation attribute if they use namespaces, and an xsi:noNamespaceSchemaLocation attribute otherwise."

This is a tad misleading.

Jython in Netbeans

Tim is working on a Java project and has posted some Java coalface notes. Dynamic language fans and Pythonistas in particular, make sure you read right up to the last paragraph.

Thursday, July 22, 2004

Searching a web page with Firefox - memories of vi

I have just figured out that "/" in Firefox allows you to search for text on a web page. No more pesky popup modal dialogs ala Ctrl-F. I like it. Brings me back to my vi days punching Ada into a VAX 11/780 on a 300 baud ADM 3A+ terminal. Those were the days...

Wednesday, July 21, 2004


Barry Feigenbaum is doing a series of articles introducing alternative languages for the Java Runtime. First up, is Jython.

Tuesday, July 20, 2004

Quantum Crypto

"Quantum mechanics is a field in which science and philosophy collide
very violently. The force of the collision sends potent particles of
wonder, bewilderment, awe and incredulity flying in all directions.

Computing is not immune to shrapnel wounds from these collisions. In
particular, cryptography is a field of computing in which quantum
mechanics looks set to make life a lot more difficult and a lot simpler
at the same time. Weird, I know, but hey, that's quantum mechanics for

Read the rest in this weeks E-Business in the enterprise column on ITWorld.

Quantum computing: A two-edged sword for security.

Monday, July 19, 2004

Many roads to quality JMS

Sometimes I come across developers who think that if you want to use messaging in Java then you get yourself a J2EE appserver, crack open a few MDBs...
You can certainly do that but there are also numerous standalone JMS implementations that can fit the bill - sometimes better than the appserver approach.
Carlos has assembled a useful list of Open Source implementations. The list includes those that are appserver based e.g. JBoss MQ.
As messaging move center stage as the key enabling tech of asynch WS, I suspect the JMS API will become as familiar to people as the JDBC/ODBC APIs of previous silver bullets :-)

XPath exprs as keys into Python dictionaries

Via Daily Python comes a link to Kimbro Staken's XPath based Python Dictionaries. Nice. The ability to simply intervene in dictionary lookups to do clever things is one of the most useful features of Python.
It really, really helps to avoid the sort of lexical scatology that comes from languages that rely on library functions for everything.

Sunday, July 18, 2004


Bill proposes a XML serialisation for RDF. Simple, readable, writable, hackable.