Exciting times ahead

I’ve been musing about the future, so forgive me for a bit of crystal ball gazing.

For years we’ve been building complex software systems, confidence that the underlying hardware was getting quicker and quicker courtesy of Moore’s law. This still boggles me; I stopped being a professional electron herder many years ago and at the time we were talking about the feature size on silicon dice getting down to the heady depths of 1 micron. There’s now people talking blithely about features in the region of a tenth of this size and this week there’s an announcement from HP that they’ve finally ┬ámanaged to fabricate the famed memristors, or at least one type of them, on silicon offering the hope of even higher densities. (Although, to be fair, memristors are not transistors which is what Gordon Moore was actually talking about.)
Continue reading Exciting times ahead

Printer Queue on Asus EEE PC and Linux

My son has an Asus EEE PC and it’s great for what he needs. He can easily carry it around and it has all the power he needs for doing his homework.

The only issue we’ve had is that our HP2605DN network printer keeps getting assigned a different IP address when we occasionally restart the network and this messes up printing from the Asus. Generally I only find out when he’s pressed print several times, so what I’d like to do is go to the print queue, remove all the pending jobs and then correct the IP address.

But the weird thing is that I couldn’t find the printer queue anywhere (we use JetDirect network printing). I searched the internet and Asus forums and just couldn’t find how to do it. The Macs on the network just find the printer using Bonjour and aren’t put out by the IP address change at all.

Finally, I discovered how to find out all about the printers and queues on the Asus EEE, you simply point your web browser at http://localhost:631. Both the Asus (running Linux) and Macs use CUPS (Common Unix Printing System™). CUPS maintains a web server on the client machine on port 631, so all you have to do is go to the web server and then you can use the web pages to see the printers and jobs, add new printers, configure printers, cancel jobs, everything you’d like to be able to do. This works on the Asus EEE, and on Macs too.

Review: Entourage 2008 vs Apple Mail

I used Entourage 2004 on my MacBook for about a year and then, in January, I upgraded to Entourage 2008. There were a couple of things I found frustrating about Entourage (especially compared with Outlook 2000 on the PC) such as the inability to easily put tables into HTML emails. But I persevered until last week when I finally upgraded to Mac OS 10.5 Leopard. The following article is a review of the pluses and minuses for Entourage 2008 versus the free Apple Mail 3.3 that comes with Leopard. Continue reading Review: Entourage 2008 vs Apple Mail

Image buttons made simple

I read a blog post recently showing how to create a button with an image and text. The button looked very simple and very nice to look at, but the HTML was more complicated than I thought it needed to be.

There is a move now to make the HTML of a document as simple and self-explanatory as possible. The HTML should contain the intent of the page, CSS (and possibly JavaScript) is then used “skin” the page as required. This has become more feasible now that browsers are finally maturing and supporting more and more of the CSS standard.

So, if we want a button, we should use the <button>…</button> tag. If we want to have an add button, we want to have:

<button class="imageButton add" 
       onclick="addSomething(); return false;">Add Something</button>

And instead of this

we want it to look like this:

Continue reading Image buttons made simple

JasperException: Failed to load or instantiate TagExtraInfo

org.apache.jasper.JasperException: Failed to load or instantiate TagExtraInfo class

(I had to shorten the article title to fit!)

I’ve just had a problem when I’ve taken a web application from my local Tomcat 5.5 development server (where it worked fine) and uploaded it onto a public server (also using Tomcat 5.5).

Continue reading JasperException: Failed to load or instantiate TagExtraInfo