Coming back to the topic of computer security, the TCP Wrapper is an example of such a safety net. I wrote it when my systems were under attack by someone who appeared to walk through walls.

Defect-free software does not exist.

I was going to visit IBM for six months as a visiting scientist. Now, six months is a lot of time, so I came with a whole list of projects that I might want to work on.

I don't expect an overnight change of all desktops to what the US Military used to call B3 level security. And even that would not stop users from shooting themselves into the foot.

However, writing software without defects is not sufficient. In my experience, it is at least as difficult to write software that is safe - that is, software that behaves reasonably under adverse conditions.

I want to avoid locking people into solutions that work only with Postfix. People should have a choice in what software they want to use with Postfix, be it anti-virus or otherwise.

Qmail out of the box works fine, so people will want to use it regardless of licensing restrictions, even when the software does not ship with their system software.

When I write software, I know that it will fail, either due to my own mistake, or due to some other cause.

The challenge with Postfix, or with any piece of software, is to update software without introducing problems.

Sure, but competition is good for the user.

As of today, the Postfix mail transport agent has almost 50,000 lines of code, comments not included.

Like all software, Qmail can survive only when it keeps up with changing requirements.

Most of the effort in the software business goes into the maintenance of code that already exists.

Coming back to the topic of computer security, the TCP Wrapper is an example of such a safety net. I wrote it when my systems were under attack by someone who appeared to walk through walls.

This will surprise some of your readers, but my primary interest is not with computer security. I am primarily interested in writing software that works as intended.

For many people my software is something that you install and forget. I like to keep it that way.

At the time the Sendmail program had a very poor reputation with respect to security, with four root vulnerabilities per year for two successive years.

One bug in an SMTP server can open up the whole machine for intrusion.

Windows favors multi-threading, which means that a service is implemented by one single process.

Writing software that's safe even in the presence of bugs makes the challenge even more interesting.

Postfix keeps running even if one Postfix process dies; Windows requires that someone restarts the service.

Lack of documentation is becoming a problem for acceptance.

The Postfix security model is based on keeping software simple and stupid.

In a previous life I wrote the software that controlled my physics experiments. That software had to deal with all kinds of possible failures in equipment. That is probably where I learned to rely on multiple safety nets inside and around my systems.

My reply is: the software has no known bugs, therefore it has not been updated.

Adding functionality is not just a matter of adding code.

I'm thinking of going to programming school. Learn how to sit down at any computer and learn to do anything on it. That's all I have left and have interest in.

I said, 'Okay, it's the year 2000, I'm getting a computer and a Palm Pilot.' I know how to check my e-mail, and I've listed some phone numbers on it. Half the time the battery has gone out so I can't use it.

To better understand why you need a personal computer, let's take a look at the pathetic mess you call your life.

I've got a computer, but I won't go near it.

All sorts of computer errors are now turning up. You'd be surprised to know the number of doctors who claim they are treating pregnant men.

All we can do when we think of kids today is think of more hours of school, earlier age at the computer, and curfews. Who would want to grow up in that world?

In OK Computer, the guitar was already moving towards a tone generator as well as a riff generator.

If you put garbage in a computer nothing comes out but garbage. But this garbage, having passed through a very expensive machine, is somehow ennobled and none dare criticize it.

Then in my early teens, when the home computer bubble was blowing, I had one of the first, an Acorn Atom, and used to write primitive adventures on that.

I compose my own stuff. I've been writing songs with words. I've been playing more on the keyboard because I can transpose it to sheet music on the computer.

I always say that my favorite game was Original Adventure, published by both Microsoft and Apple Computer back in 1980.

To err is human - and to blame it on a computer is even more so.

I think computer science, by and large, is still stuck in the Modern age.

It would be nice to design a real briefcase - you open it up and it's your computer but it also stores your books.

I am the farthest thing from a computer genius.

I wish I could have 25,000 years of my personal family history documented in a very powerful computer or a CD-ROM that I could just pop in and my computer would never crash.

The basis of computer work is predicated on the idea that only the brain makes decisions and only the index finger does the work.

In my second year in graduate school, I took a computer course and that was like lightening striking.

Some people may have noticed the new computer shelf at the anchor desk. Rather than phone calls, we want to take real time e-mails, and we'll be starting that very soon.

The cloning of humans is on most of the lists of things to worry about from Science, along with behaviour control, genetic engineering, transplanted heads, computer poetry and the unrestrained growth of plastic flowers.

The fact that biological, or "natural" rules might help in the creation of a computer generated work of art is interesting, but even a wonderful work of art made in this fashion isn't the same as a person, with all his or her experiences and emotions involved, making art.

Computer modelling for weather forecasting, and indeed for climate forecasting, has reached its limits.

The computer can't tell you the emotional story. It can give you the exact mathematical design, but what's missing is the eyebrows.