Error Free Software?

One of the more interesting questions in software engineering today is “Is it possible to produce error-free software?”

Advocates of various technological advances tend to argue that, with whatever approach they are advocating, error-free software is indeed possible. Software old-timers are, at best, dubious.

A recent study casts important light on this issue. That study sets out to explore the related question “Can state-of-the-art software engineering methods guarantee reliability?” As it turns out, perhaps surprisingly, the answer was “no”.

– Robert L. Glass, Error-Free Software Remains Extremely Elusive, IEEE Software, Jan/Feb 2003, Volume 20, No 1

Doesn’t surprise me at all.

Internet Banking - Security vs Usability

I have found that the internet can be a very useful way for me to keep on top of my various personal banking activities. Today I tried to set up on-line banking for the company. It was an ordeal.

I had tried to do this about six months ago but was put off by the forms that needed filled in and the cost. However, the last time I visited the bank manager he informed me that the service I wanted to use on-line, viewing account information, was free. So I sat in his office and filled out the forms. He sent this away and about a week later I received my registration code. However, the registration code wasn’t enough for me to register for the service. I had to ring the bank and get another secret code and would have to provide security information to prove my identity. Why couldn’t I have been given these codes whilst I was in the bank? Anyway, I rang the bank where I was re-directed to another department, asked to type in my registration code, was then re-directed to yet another department who asked me for my registration code (again) and for three pieces of security information. But I still didn’t have a secret code. To get this I had to provide three pieces of new security information that they would use in case I ever decided to ring again!

The most irritating thing about this whole process was that no-one I spoke to in the bank knew why I was ringing. Even though I phoned the number given to me in my registration pack I still had to explain to everyone I spoke to why I was ringing. And as for having to tell someone my registration number when I had just typed it into the phone…

When I finally had the two codes I required I went to the web-site to see if I could register. To do this I needed to download an applet onto my machine. This probably means that I will only be able to access the information for this one computer. I also had to provide a password to use when I wanted to access this site. This is a normal requirement for any web site but in this case they wanted the password to contain at least four words!

I know it is important for internet banking to be secure but it also needs to be usable.

Eye Shadow

Marc points out that he doesn’t believe that he is the only person to ever borrow eye shadow from me. He is correct – lots of females have borrowed eye shadow from me – he is the only man to have done this!

Using CSS to Add Images to List Items

I was working on a new site and I wanted to put an image in front of all the links that appeared as lists. Tony had told me that it was possible to do this using CSS. As with many of the things that I have been told are possible using CSS it took me quite a while to work out how to do this. I would have got the job finished much sooner had I read this post first. Mark’s article showed me how to use the list-style property to change the appearance of a list bullet. For example

<style type="text/css">
ul.URLlist {
  list-style: url(/images/arrow.gif) disc;

replaces the standard bullet with arrow.gif in modern browsers.

Even though I had the image I wanted as the list bullet I still had problems. The image was appearing outside the content area of the UL, which didn’t work with the design. I had read an article in the past about the positioning of markers on list items which I went and looked up again. After reading this I used the list-style-position property to move the image so that it appeared inside the <li> box.

<style type="text/css">
ul.URLlist {
  list-style: url(/images/arrow.gif) disc;
  list-style-position: inside;

On further reading I realised that instead of using the list-style-position property I could have added the value of inside to list-style and it would have done the right thing.

list-style { url(/images/arrow.gif) disc inside; }

I was really pleased with the results of my work until I discovered that this doesn’t seem to work with DL, DT, or DD. So, how do I get an image to appear in front of these?

IEEE Fellows' Survey

A remarkable two-thirds of the Fellows[IEEE] thought that open-source computing had a very important role to play in the computer industry. Many noted that competition is a healthy catalyst in the marketplace and took aim at the Seattle giant.

…And while a few expressed some doubt that open source could cure all software’s ills, many seemed to agree with the respondent who wrote, “In a economically difficult environment, open-source computing offers an opportunity for talented individuals to contribute for the benefit of all”.

– Ashton Applewhite, 2003 Technology Survey, IEEE Spectrum, January 2003

Nothing to Say

It’s been one of those weeks when I haven’t been able to think of a single thing to write in my blog. None of the books I’ve been reading have had any interesting quotes, none of the papers I’ve been reading have made much sense (I’ve been researching data mining) and nothing I’ve been working on has inspired me to write.

Spreading Emotions

Emotions may spread like viruses, but not all emotions spread with the same ease. A study at the Yale University School of Management found that among working groups, cheerfulness and warmth spread most easily, while irritability is less contagious and depression spreads hardly at all. This greater diffusion rate for good moods has direct implications for business results. Moods, the Yale study found, influence how effectively people work; upbeat moods boost cooperation, fairness and business performance.

– Goleman, Boyatzis & McKee, The New Leaders