Top of Bill's reasons why the company should not be forced to open up its software is the claim that the individual components are so tightly integrated that such changes are effectively impossible.

But hang on... didn't we hear a similar claim from Bill's boys a couple of years ago -- only to have them shown up as nothing but hype?

This time however, I really think that Bill is telling the truth -- and that explains why MS Windows and other Microsoft applications are such a wonderful playground for hackers, virus writers and other malevolent sods.

Unless things have changed a whole lot since I was a programmer, one of the key strategies when trying to write software that is correct, robust, reliable and easy to maintain -- is modularity.

In fact the concept of "modular programming" has been a cornerstone of the software industry for as long as I can remember.

An essential element of producing modular code (with all the desirable attributes listed above) is to compartmentalise functionality such that its internal workings are accessed through a well-defined and well documented interface.

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Modular programming also promotes another desirable trait -- reusability.

This means that instead of duplicating the code for a commonly used operation, it can be turned into a module and re-used whenever that function is required throughout the program. Older (FORTRAN or BASIC) programmers will have implemented such reusable components as "subroutines."

When Pascal and C arrived on the scene, these little snippets became procedures or functions. And, with the arrival of object-oriented languages, some of them morphed into objects that are defined by "classes."

These small modular, re-usable bits of code are then used to create larger, more functional modules which, in turn, are used to create even larger, even more functional modules - and so on -- until you have the top-most layer which is the application itself.

(Note for experts: I realise that I've described the "bottom-up" method when top-down is far more commonplace -- but the concepts of nested modularlity are the same).

The end result is that any program, or part of that program consists of a well defined and organised group of modules that cooperate in a well-defined manner. Changing or removing a single part of a program can then be done with full understanding of the effects and minimal disruption to the rest of the code.

Now that we've finished the brief history of programming I'll get back to the point I'm trying to make.

Well designed software doesn't consist of a huge monolithic block of code such as the one Mr Gates appears to be claiming has been used to build Windows.

Large lumps of code little in the way of modular structure are notoriously hard to build, test and debug.

Now can you see where I'm headed?

This morning we have yet another report of an expert uncovering multiple flaws in Microsoft's IE6 web-browser -- the very browser that Microsoft says is too tightly integrated into Windows to remove.

Now I'm sure that Microsoft didn't set out to create a huge, unmanageable block of code that ignored many of the basic rules of good programming -- but even the best project can degrade into an unmanageable mess of endless, poorly documented interdependencies if care isn't taken.

What's more, this degradation from nice modular system into a monolithic mess often happens in response to the need to fix bugs and add functionality to very tight deadlines. Such pressure often forces programmers to break the rules and take shortcuts in order to keep the marketing and management teams happy.

Unfortunately, once you start such a downhill slide it becomes a vicious circle that can be impossible to break.

So, are Microsoft's seemingly endless list of security holes and bugs a direct result of abandoning one of the oldest and most basic of programming disciplines perhaps? Maybe they don't want to share their code because they'd die of embarrassment?

Come on Bill -- If your code is up to spec then you should be able to rip out any single module of your OS or applications and allow third-party replacements by simply publishing the programming interface specifications.

XTRA Double-charging For Over-Cap DSL Traffic
I spoke to Matt Bostwick over at XTRA yesterday to try and get some answers to the issues raised in recent Aardvark columns regarding their crazy caching proxy server.

Following that conversation it appears that Aardvark is no longer being over-cached (hooray) -- but many of the other overseas sites I rely on for news still are.

If you're an over-cap DSL user who is paying $0.10-$0.20 per MB to access overseas websites be warned -- if you want the latest version of pages from these sites you will actually be paying DOUBLE the price thanks to XTRA's cache.

Yes, when you enter the URL of a site that is being incorrectly cached by XTRA you will get the last cached version. To get the LATEST version you will have to hit refresh. XTRA will charge you the going rate for BOTH copies -- so you're paying twice. In effect, XTRA may have ripped you off the first time by selling you an old version which, in the case of news, might be already well out of date.

So -- XTRA have slapped a bandaid on their ill-mannered caching proxy to address my own copyright issues -- but they're still rorting over-cap DSL users who just want to access up-to-date content from other international websites.

Is this incompetence or just a smart way to earn extra money?

I'm not going to provide XTRA with a long list of sites that should also be excluded from their caching proxy-server's grubby little hands. I want them to revise their caching rules to put the interests of their customers ahead of the desire to engage in gross profiteering.

This whole issue has generated a raft of correspondence from readers -- and several have asked "why are you picking on XTRA" -- which is a valid question.

Well XTRA is NZ's largest ISP so its caching practices are likely to have more effect than those of any other ISP. Secondly, I'm not in a position to comment on the caching practices of any other ISPs because I don't use them and therefore can't test them.

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