Sunday, October 29, 2017

My most challenging experience as a software developer

Here is my detailed answer to the question, "What is the most challenging experience you encountered as a software developer?:

We were developing the tracking system for Project Mercury, to put a person in space and bring them back alive. The “back alive” was the challenging part, but not the only one. Some other challenges were as follows:

- The system was based on a world-wide network of fairly unreliable teletype connections. 

- We had to determine the touchdown in the Pacific to within a small radius, which meant we needed accurate and perfectly synchronized clocks on the computer and space capsule.

- We also needed to knew exactly where our tracking stations were, but it turned out nobody knew where Australia's two stations were with sufficient precision. We had to create an entire sub-project to locate Australia.

- We needed information on the launch rocket, but because it was also a military rocket, that information was classified. We eventually found a way to work around that.

- Our computers were a pair of IBM 7090s, plus a 709 at a critical station in Bermuda. In those days, the computers were not built for on-line real-time work. For instance, there was no standard interrupt clock. We actually built our own for the Bermuda machine.

- Also, there were no disk drives yet, so everything had to be based on a tape drive system, but the tape drives were not sufficiently reliable for our specs. We beat this problem by building software error-correcting codes into the tape drive system.

We worked our way through all these problems and many more smaller ones, but the most challenging problem was the “back alive” requirement. Once we had the hardware and network reliability up to snuff, we still had the problem of software errors. To counter this problem, we created a special test group, something that had never been done before. Then we set a standard that any error detected by the test group and not explicitly corrected would stop any launch.

Our tests revealed that the system could crash for unknown reasons at random times, so it would be unable to bring down the astronaut safely at a known location. When the crash occurred in testing, the two on-line printers simultaneously printed a 120-character of random garbage. The line was identical on the two printers, indicating that this was not some kind of machine error on one of the 7090s. It could have been a hardware design error or a coding error. We had to investigate both possibilities, but the second possibility was far more likely.

We struggled to track down the source of the crash, but after a fruitless month, the project manager wanted to drop it as a “random event.” We all knew it wasn’t random, but he didn’t want to be accused of delaying the first launch.

To us, however, it was endangering the life of the astronaut, so we pleaded for time to continue trying to pinpoint the fault. “We should think more about this,” we said, to which he replied (standing under an IBM THINK sign), “Thinking is a luxury we can no longer afford.”

We believed (and still believe) that thinking is not a luxury for software developers, so we went underground. After much hard work, Marilyn pinpointed the fault and we corrected it just before the first launch. We may have saved an astronaut’s life, but we’ll never get any credit for it.

Moral: We may think that hardware and software errors are challenging, but nothing matches the difficulty of confronting human errors—especially when those humans are managers willing to hide errors in order to make schedules.

Monday, October 23, 2017

Where do old programmers go?

As far as I can tell, I’m the oldest old programmer to answer this question so far. I’m so old that the title “programmer” didn’t even exist when I started.

I celebrate my 84th birthday this week, and as far as I know, most of the programmers who were around under various titles when I started (in 1956, maybe 20 of us in the USA) are now dead. I hope they’ve gone to heaven (the cloud?).

Myself, I gradually ceased writing code for money and transitioned to training younger people to be outstanding professional programmers. I still write lots of code for my own use and amusement and learning, but it’s been at least 40 years since I could tolerate writing code for a boss who didn’t understand what programming was all about.

I’ve earned multiple livings as consultant, teacher, and writer. Always about programming, but more about design rather than coding details as the years went by. If you’re good, you can do any of these things even at advanced age, but you can’t just sit around waiting for someone to find you.

If you’re not good, than either get good (it’s never too late) or retire. We don’t need mediocre programmers, and we never did.

Sunday, October 08, 2017

How Can I Have More Leadership?

I was asked, "How Can I Have More Leadership?"

Many people were interested in my answer, even though I'm not sure whether this question means

How can I have more leadership applied to me?


How can I provide more leadership for others?

In some ways, it's the same question either way. Why? Because if you want more leadership applied to you, the primary way to get it is to provide it yourself.

There are many things you could do to provide more leadership, but I would suggest that before you do any of them, set your mind firmly on this definition of leadership:

“Leadership is the ability to enhance the environment so that everybody is empowered to contribute creatively to the task.”

Don’t forget any of the key words. Check them out when you’re about to do something you think of as “leading.”

  • enhance: you’re making the environment better in some way, and there's lots of way to do that, not one single "leader" way

  • for everybody involved, so make sure what you think is an enhancement is really that for everybody

  • so they’re empowered, which doesn’t mean forced or ordered, especially not by you

  • creatively, not in some stupid or mindless way, and not necessarily in the way you would do it

  • and stay on task, for your job is not to fix everyone else, but to help the job at hand get done

If you keep these things in mind, you won’t always be perfect at leading, but with practice you’ll get better and better, with fewer blunders.

Monday, October 02, 2017

Can they charge me for bugs?

How likely is it that you can create 0 software bugs?

A contract programmer told us, "For years, my client has aimed for 0 bugs on every software release. However we can't control the bugs that closely. Now the client has come out with an idea of charging me a penalty—a cost refund as much as 3% per bugs from what I charge them. What can I do?"

First of all, stop calling them “bugs.”  They are not independently reproducing life forms. They are made by us humans, and there are no perfect humans.

Next, listen to what experienced S/W developers will tell you. Perfect software is a myth, an illusion.

But suppose you did produce a piece of zero-error software. How would you know that’s what you had? I’ve known software that was thought to be error-free for 30+ years, then an error turned up. Are they still going to be charging you penalties thirty years from now?

Quite simply, perfect software violates the Second Law of Thermodynamics. Then, too, software that might be perfect yesterday can become imperfect because of changes in the world today.

But, if they want to charge you for errors detected in software you built, that’s okay. What you need to do is charge them more for the software to begin with, to account for what you will eventually have to pay back. Just set a time limit—maybe a year or so, or until someone else modifies the code. And be sure you have an agreed definition of what constitutes an “error.”

This is not a simple question. I’ve written at least two books on the subject, and ultimately they don't cover every possible variation. But at least give your client a copy of the books so you can begin your negotiation with some intelligent information, not just myths and illusions: