Wednesday, November 15, 2017

What's it like to rewrite a program from scratch?

This is an interesting question because so many programmers are so afraid of this task that they would never even ask it. Is this reluctance agile, or Agile?

But why would you want to do rewrite a program from scratch? The most important reason is to increase maintainability. In the initial writing, the focus is generally on merely getting the job done, without thinking of the program's future. Over their lifetime, many programs cost far more to maintain than to write originally, especially when the original program has become a thing of rags and patches.

A second, and often secondary reason to rewrite a program is efficiency. Newly constructed programs and highly patched old programs sometimes turn out to be slower than desired, but such inefficiency cannot erased by any amount of tweaking. Instead, increased efficiency requires a new approach, an approach that needs to be implemented from scratch.

But isn't rewriting expensive? Not usually. In fact, it’s generally far, far easier to rewrite a program from scratch than to write some brand-new program.

Why would a fresh start-over be cheaper than the original? Because in writing the original program, the original programmers answered so many difficult questions about what was really wanted. Requirements haven't changed, and most of the thought put into testing can be reused.

Those questions—requirements and test—usually make up more than half the total work put into a program. They have already been answered—but only if you resist the temptation to change those answers. If you don’t resist, then rewriting the program can be arbitrarily difficult.

I wish more programmers had to courage to rewrite some clumsy programs from scratch, rather than patch and patch and patch. And I wish their managers would encourage sensible rewriting, rather than force programmers to waste their skills, time, and energy keeping ancient programs on life support.


Tuesday, November 07, 2017

When do I know I'm not a beginning programmer any more?

I was asked, "When do I know I'm not a beginning programmer any more?"

I wouldn’t answer this question, because it’s the wrong question.

You should not ever want to know you’re not a beginner, because a true professional is always a beginner. The world in general, and the world of programming in particular, is so complex, so huge, that one lifetime is not long enough to stop being a beginner.

Your beginner’s mind is one of your most valuable tools. It requires you to look at each situation afresh, and to innovate. (Fundamentally, that's what the Agile movement is all about.) If you know children, watch how they use their beginner’s minds to conquer their world.

I’m very suspicious of people in the programming field who think they are no longer beginners. Myself, I’ve been programming for about 70 years, and I still consider myself a beginner.




Thursday, November 02, 2017

How do I become a programmer who gets stuff done?

The young man wanted to know, "How do I become a programmer who gets stuff done?" He received a number of good answers, like how to organize his work and schedule his working hours. Yet I had a different view of things, so I gave a different sort of answer, as follows.

Some good advice here, yet even if you do all these suggested things, you may be having a different problem. When you speak of getting stuff done, you may be speaking of “finishing” things.

Defining what “done” means has been a classic programmer problem for more than 50 years. Part of the problem is that programmers with different personalities have different ideas about what “done” means. For instance, look at the situation from the point of view of MBTI personality temperaments:

NTs tend to think a project is done when they have a clear description of the problem and a general approach to solving it. Someone else can work out the details.

SJs tend to think a project is done when it’s “code complete”—though research at Microsoft and other places seems to indicate that only about two-thirds of the eventual code has been written by that supposed benchmark. Perhaps this work isn't thought of real programming, but only "clean up."

NFs, such as me, tend to think that a project is done when everyone involved is satisfied that it’s done. Of course, because these "others" are of various personality types, our NF estimate of "done" isn't very reliable.

SPs tend to think a project is done when they are bored with doing it. They share this feeling with lots of other temperaments, too. Programmers in general don't tolerate boredom very well.

Not taking that last step to "clean up" is a curse of our profession, leaving many programs in a less-than wholesome state. Unclean, unfinished programs are the source of many maintenance problems, and of many errors shipped to customers.

Of course, this classification is only a rough model of non-finishers. Many good programmers of all temperaments are excellent finishers, having taught themselves to be aware of their tendencies and counter them with a variety of tactics. Primary among those tactics if the technical review by peers (which is an integral part of the Agile approach but  by no means is not confined to Agile).

So, you offer your “finished” project to your peers for review, and if they agree that it’s finished, you’ve truly gotten something “done.”

If they don’t agree that your work is done, they will give you a list of issues that you need to address before you’re “done.” You then go back to work and address these issues, then resubmit the newest version to another technical review.

Finally, you iterate in this reviewing process until your work passes the review. Then you know you’ve gotten something done.

For more detail on the review process, see, 


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?

or 

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: