Tag Archives: Computing

Opinion

Extreme Programming Explained

Introduction

Naturally the key selling point of Extreme Programming — reduced risk and increased fun — appeal to me. I’ve worked on many projects that were either risky, no fun or both and any way to improve that would be a good idea.

However, most of the successful projects were run using fairly heavy-weight methodologies, CMM or ISO accredited, for example. Extreme Programming promises to deliver the benefits while still being simple. I was sceptical. This sounds a little too close to one of Fred Brookes Silver Bullets.

How does it work?

Extreme Programming sounds too simple to ever work. None of its components are new or especially controversial, some are even very common throughout the industry. What’s new is their application together. The key is that the strengths of one part paper over the weaknesses of others.

I won’t detail all the bits — that’s what the book is for — but there are a couple of things I want to talk about.

The one thing that came through in all other reviews of the book was the pair programming aspect. The idea is that whenever writing code, there are always two people sat at the computer. This sounds very wasteful of resources but is based on some very sound theories: reviewing code is good and sharing knowledge around the team reduces the dependency on any one person. XP takes it to the extreme (hence the name) by having, in effect, every line of code being reviewed by two people all the time.

I can certainly see the benefits, but I can imagine a client being very suspicious when you suddenly have two people appearing to do a job you previously only had one doing. He also proposes using a utilisation metric which documents that people are actually not doing genuinely productive work all the time.

Anyone that writes software will immediately recognise that a lot of time is spent helping colleagues, in design or review meetings and any number of other things that are not directly and visibly related to increasing the functionality of a program. Making it more visible sounds like a much harder “sell” than is suggested in the book.

Is it easy to understand?

Brock is clearly very enthusiastic about his methodology and this shows in his prose, which is clear, friendly and concise. It’s sensibly organised and it usually answers questions you’re thinking of in just the right place.

However, it only does all that if you remember what the book is trying to explain. It’s trying to explain Extreme Programming not how to implement it effectively. I had a little difficulty seeing how you could automate tests in some environments. We tried and failed with Oracle Forms (or whatever it’s called this week) for example. I don’t disagree with the principle, but there are some definite technical barriers that are not even acknowledged.

I’m not sure that the distinction between describing what XP is and how to implement it is a good one. It sounds like an excuse to sell two books when only one would suffice. Why would anyone be interested in learning the theory but not the practice of a simple methodology?

Disadvantages

Beck does not claim that Extreme Programming works in all circumstances. There’s an entire (albeit short) chapter on it, which is quite refreshing. Most people would claim that their baby was ideal in all circumstances!

I only thought of a couple of other problems that are not addressed, although neither are necessarily any more of a problem with XP than with other methodologies. (However, they are areas that are claimed to be addressed.)

Documentation is never kept up to date anyway, and in XP there is a much greater chance of at least one person knowing how it works. Couple that with a full set of tests, the ‘business’ person being on the team right from the start and, well, what’s my problem?

The problem is identified in Death March. Who are the stake holders on the project? Is it your team-member (the end user)? Is it their manager, who might want a bunch of reports? Is it the CTO who doesn’t actually care what the system does and just wants a success of some kind in order to get promoted?! The book and the Extreme Programming approach treat the problem of requirements as something that is eventually known and is fix-able given close enough interaction with the users. I wish that were true.

Beck might suggest that this ‘unknown’ is just another form of change than can be managed in the normal manner, but my guess would be that the magnitude of changes required by people that don’t have day-to-today access to the team would be too big and would break the process.)

Or perhaps this is just a size issue. With a system, with a small number of well-defined users there’s no reason it couldn’t work.

Conclusion

I think my initial and immediate dislike of XP stemmed from the fact that most of the projects I’ve ever worked on have fallen into the “won’t work” camp. Now that I understand its background I can appreciate it much more.

And it’s only fair to note that this appreciation comes solely from the book. It’s worth reading even if you don’t plan on implementing Extreme Programming.

The facts

Author: Kent Beck

Cost: $29.95

ISBN: 0-201-61641-6

Opinion

Dreadful Thoughts

Introduction

I have a terrible confession to make. I am not a spiritual man so, rather than seek penance through the church, I shall document my reasoning here on the web and you can make your own conclusions.

Please go easy on me.

My confession: I can see myself buying a Macintosh later this year.

To some, that may not sound like something to be ashamed of but it’s all a matter of perspective. By trade and education I’m an engineer or scientist; I have short hair, no piercings and virtually no artistic ability (I present the evidence of that here on this web site!). My computer of choice tends to have a barren, baroque user interface. Let’s be honest here, it’s Unix.

The Macintosh and Unix sit virtually on opposite ends of a spectrum. It’s usually called usability, but I think it’s even more precise than that. The Mac makes it easy for people to learn how to use it. Apple make things easy to use and they sacrifice power and flexibility in order to do that.

One of the best examples if this extreme position is the mouse. In Unix you tend to have three buttons. Windows originally had two but now seems to have spawned wheels and more buttons than a Space Shuttle. In each case although it only takes a short time to realise that the left button does most of the useful stuff, Apple decided that one button was less confusing. They’re right, of course. But it does limit your options as far as, say, short-cut menus are concerned.

Unix is the opposite. It has a huge learning curve, but an expert can quickly do just about anything. After spending a lot of time on that curve, I’d actually say that Unix was more usable than a Mac. I’m under no illusions, though, that it’s more difficult to learn.

I guess these extremes, to some extent, explain the success of Windows. Ignoring Apples mistakes and the fragmentation of the Unix market in the early nineties, we can see that Windows is easier to use than Unix but much less so than a Mac. It has the Start menu, Wizards, pop-up help and often hides information rather than bombard the user with difficult, unnecessary detail. On the other hand, it does have rough and ready multi-user facilities, solid TCP/IP networking and a command-line interface (for the brave). It fits the middle ground doing neither task especially well.

The battle ground

That’s how they stand right now, but six months from now things may be very different.

The Unix side probably isn’t going to change much. Linux, especially, will continue with its vast range of incremental upgrades. distributions will eventually come on-line with the new 2.4 kernel, and improvements will continue in both the KDE and GNOME environments.

In the same time-frame, the next desktop version of Windows, XP, will be unleashed on the world. The beta’s are currently doing the rounds and people seem generally impressed. The interface is easier, more consistent and more aesthetically pleasing, and its built on the Windowds 2000 core which has generally been well recieved.

Normally it might have been enough for me to upgrade from my old copy of Windows 95. But for two things: you can’t, you can only upgrade from Windows 98 or above; and MacOS X.

It would be an obvious choice to buy a new PC preloaded with Windows XP since I’ve had a small succession of similar machines over the last ten years, but I find the improvements in MacOS X to be so compelling than I’m considering moving to a completely new architecture. In a sound-bite those reasons are power and user-friendly in one.

MacOS X is based on a BSD Unix kernel (called Darwin and available under an Open Source licence) and has an enhanced Macintosh user interface grafted on top. This is truly the key. You have the complex internals available from a command-line when you need it and a state of the art GUI when you just need a word processor.

In conclusion

There is only one other operating system that supports such a neat combination of Unix and User Friendliness (the BeOS) and that has many problems: I have tried it on three machines and all have had some device that is unsupported, so this can hardly be a unique scenario; and the software support is worse. I may prefer not to use Microsoft Office, but I need to be able to exchange files with people that do.

No other operating system will have quite that level of flexibility. Microsoft won’t be adding more Unix like functionality to Windows and the open source community just can’t compete with the many years of experience that Apple have designing computers for people who don’t write code.

Languages

C

Introduction

Talking about C is not easy. Almost all professional programmers have used it at some point and many have a strong attachment to it. I don’t want to start by saying that it’s a poor language, alienating much of my audience, but I figure I’m going to end up doing that anyway so I may as well get it out of the way at the beginning.

Compared to many languages that have come since, and even some that came before, C just isn’t a very good language.

There, I’ve said it.

History

Perhaps more than almost any other language since, C has a rich and famous history. It’s almost impossible to discuss it without also talking a little about the history of Unix.

In 1969, Ken Thompson finally got hold of a PDP-7 and decided to write an operating system for it. (It happened more often than you’d think back then.) That operating system was Unix.

A few years later, Dennis Ritchie designed and built a language based on B (itself based on a language called BCPL) and, creatively, called it C. Unlike its immediate ancestors, C had types and a number of other useful bits and pieces.

C was so useful that Unix was quickly rewritten in it. These days that sounds obvious, but until that point operating systems had always been written in assembler or machine code. This is an important part of computer history.

Utility

C became popular largely because it filled a very useful niche. At one extreme you have all the ‘real’ languages. At the time, real computer scientists would have used Algol68. Structured and clever, Algol was a great language but you couldn’t do anything very low level with it.

At the other extreme there is assembler which people had to resort to if they wanted to do anything close to the hardware. Assembler is only one step removed from machine code which makes writing reliable, bug-free code very difficult, especially when you’re building something as large and complex as an operating system.

C fits in the middle. Described by some as a high-level assembler, it allows you to do low level coding, accessing particular memory addresses and the like, and use high-level constructs such as functions and types.

The following books and papers helped me learn to hate C.

“Practical C Programming” by Steve Oualline.

“Writing Solid Code” by Steve Maguire.

“Code Complete” by Steve McConnell.

Hello world. How many nasty ways can you write “Hello World” in C?

Pointers

Key to C’s ability to mix high- and low-level constructs are pointers. Most ‘serious’ languages have some concept of a them. Some call them references, some call them links, but they all, basically, refer to something that identifies a chunk of memory. Most other languages only use them when you have to, but they are C. No pointers, no language.

You want an array? That’s really a pointer. Pass by reference? A pointer. Strings? Ah, they’re arrays! (Which are pointers.)

The advantages of using pointers for just about everything in the entire language are mainly one sided: it makes writing compilers easier. For the poor souls that actually end up using the language all is not so rosy. As Steve McConnell puts it, “pointers are one of the most error-prone areas of modern programming” (Code Complete, section 11.9).

Some of the side-effects of using pointers are not immediately apparent, either. In most languages, arrays have bound-checking (the ability for the language to raise an error if you try to access an element that doesn’t exist). But C doesn’t really have arrays, it has pointers and a little syntactic sugar that makes it look like it has arrays. Pointers don’t know how much memory is being pointed to so you don’t get bound-checking. If you’re lucky your program causes a segmentation fault, if not you might corrupt other data or, on some operating systems, your program.

It takes all types

Another one of C’s biggest problem is it’s typing. As most people will already know, C allows you to put numbers into character variables, integers into floating points and any number of other nasty combinations. To C they’re all valid, but what they do are not always well defined or consistent. Even the same compiler sometimes does different things depending on the level of optimisation in use, the phase of the moon, etc.

The odd thing is that a weakly typed language doesn’t allow you to do more than one with strong types, it merely allows you to do the wrong thing more easily. For a language used for large-scale software engineering projects the risk of poor code is just too great and weak typing should be outlawed.

I’m sure that people are going to mention the myriad of warnings that modern compilers are able to produce, or that ‘lint’ has been available for nearly as long as the language has been. My counter-argument: I don’t see why you should have to add extra tools or read through pages of warnings in order to correct deficiencies in the source language!

The good bits

If C was truly as appalling as I’ve made out so far, no-one would actually be using it. The main ‘win’ for C, as far as I can see, is that it is small, well defined and widely available.

All three merits are in many ways different sides of the same coin (if you can imagine a three sided coin). To make the language well defined, it helps if it’s small. If lots of people are to use it, it needs to be simple enough that they aren’t put off (Ada anyone? Thought not.). Small and well-defined make it easier to write compilers too, meaning that it’s available on everything from the lowliest PC right up to mainframes.

The theory also goes that your programs should recompile on this range of machines too, but that’s not as true as we’d all like to think. If it was true, we wouldn’t need Java or hundreds of ‘#ifdefs’ throughout. My code tends not to be that low-level, but I wouldn’t like to make any promises about its portability. However, that doesn’t make C’s wide availability useless. Even if your program isn’t cross-platform, the skills required are. A C programmer can quickly write code for just about any machine.

Summary

I’ve probably written more lines of C code than just about any other language, so when I say that I don’t like it I hope that you can see that I’m not being narrow-minded or prejudiced.

As I’ve mentioned above there are some things that I like about C, it’s just that there is so much to hate about it and, even at the time it was written, there wasn’t an excuse for it!

The languages main features are its weak typing and over-use of pointers, both of which allow developers to make truly horrendous coding errors with ease.

If those were C’s only problems I might be able to forgive it, but they aren’t. C has more ways for both experienced and novice programmers alike to hang themselves than any other language I can think of (with the possible exception of Intercal). Even if it didn’t have the ‘=’ and ‘==’ operators to confuse, there’s still the wonderful ‘?:’ and a whole host of spectacularly error prone API calls (does all your code check the value that ‘malloc’ returns?)

No, C, as a language, is a dinosaur. It deserves to whither and die. If you write anything other than an operating system kernel and use C, switch to another language. You’ll be far more productive when you start battling the problem rather than the language.

PL/SQL

Output

Introduction

PL/SQL is good for many things. It has a structured, Ada-like syntax and can have SQL statements seamlessly embedded in it. Although not compiled right down to machine code, it’s even fairly quick.

But one thing that most people initially have difficulty doing is displaying information on the screen. The first thing I did was to enter what I wanted into a temporary table and use SQL*Plus to select from it. This works well for reports at the like, but it doesn’t work at all if you want to display something independently of a transaction or halfway through a function.

I was frustrated that there wasn’t a better way of feeding back information to end users. I was wrong to be frustrated: there is a better way.

Hello world!

The best example I can think of doing is the world famous “Hello, World!” program, so here goes:

CREATE OR REPLACE PROCEDURE hello_world AS
BEGIN
     DBMS_OUTPUT.PUT_LINE ('Hello, world!');
END hello_world;
/

In SQL*Plus you can run that procedure by typing “exec hello_world” and pressing return.

You may be surprised to see that it says “PL/SQL procedure successfully completed.” and nothing else; there’s no “hello world” text. Surely it’s lying, it hasn’t successfully executed anything, has it?!

As with most things Oracle, things are not quite as simple as they first appear. In this case you need to tell SQL*Plus that you’re going to use the DBMS_OUTPUT package. To do that, you need the following command:

set serveroutput on

You might want to put this in your “login.sql” file so that it gets executed every time you log in. You can also add the “size” parameter to the end to indicate how much output you’ll be producing. The most you’re allowed is around 1Mb so I usually type “set serveroutput on size 1000000”.

If you try executing the procedure now, you’ll find that it works correctly.

A longer example

For our second and final example, we’ll use one of the tables that Oracle installs by default. It’s called EMP and should be in the SCOTT schema (password TIGER). The important fact here is that there are a number of different columns types, NUMBER’s, VARCHAR2’s and DATE’s.

On to the example:

CREATE OR REPLACE PROCEDURE example2 AS
     CURSOR emp_cur IS
         SELECT e.empno, e.ename, e.sal, e.hiredate
         FROM   emp e
         WHERE  e.sal > 2500;
    BEGIN
     FOR current_employee IN emp_cur LOOP
         DBMS_OUTPUT.PUT_LINE ('-------------------');     -- string literal
         DBMS_OUTPUT.PUT_LINE (current_employee.empno);    -- number(4)
         DBMS_OUTPUT.PUT_LINE (current_employee.ename);    -- varchar2(10)
         DBMS_OUTPUT.PUT_LINE (current_employee.sal);      -- number(7,2)
         DBMS_OUTPUT.PUT_LINE (current_employee.hiredate); -- date
         DBMS_OUTPUT.PUT_LINE ('Year: ' ||
                               TO_CHAR(current_employee.hiredate, 'YYYY'));
     END LOOP;
 END;
 /

This code should be pretty much self-explanatory. We first start a loop over a table. Inside the loop we output the content of it. The first PUT_LINE statement shows that you can output a string literal (we know this as ‘Hello world’ is one too). The second shows that you can output numbers without first converting them to a string — the function is overloaded and will accept most standard types.

Following that theme, the third, fourth and fifth lines output a string, a different number and a date, in all cases using the default format string. The last PUT_LINE statement shows that you can output expressions, but note that it all needs to be of the same type (so in this case I convert a date to a string so I can concatenate it to another string).

On my machine, the output is as follows:

SQL> set serveroutput on
SQL> exec example2
 -------------------
 7566 
JONES 
2975 
02-APR-81 
Year: 1981 
------------------- 
7698
 BLAKE 
2850 
01-MAY-81
 Year: 1981 
------------------- 
7788 
SCOTT 
3000 
19-APR-87
 Year: 1987 
------------------- 
7839 
KING 5000 
17-NOV-81 
Year: 1981 
------------------- 
7902
 FORD 
3000 
03-DEC-81 
Year: 1981
PL/SQL procedure successfully completed.  
SQL>

Conclusion

As we’ve come to expect from Oracle over the years, simply outputting a little text to the screen isn’t quite as easy as you might wish for.

And it’s not without it’s problems. If you want to send more than a megabyte to the screen, you’re still going to have difficulty and all the playing around with “set serveroutput” is just plain tedious.

However, the important point is that you can do it and, programatically, it’s (basically) just a single command.

If you want more information on this kind of thing, have a look in chapter 6 of Oracle Builtin Packages, a whole book dedicated to this kind of thing.

Free Software Howto

Free Software HOWTO

v1.2, 17 January 2001

With the current Linux trend towards multi-million dollar IPO’s and “Open Source” software, much of the emphasis of “free” software has been lost leaving people new to the fold confused and not completely understanding all the implications. This HOWTO will, hopefully, reduce some of that confusion.

Introduction

What’s in here?

This document talks in non-technical terms about free software, what it means and why you should care about more than just the cost of your software.

Who is this HOWTO for?

People that have been hacking for years will already be fully au fait with the content of this document. Or at least you should be!

The Free Software HOWTO is aimed at people new to Linux, Open Source or free software.

New versions of this document

The official home of this HOWTO is here. You will always find the most up to date version here.

Disclaimer

You get what you pay for. I offer no warranty of any kind, implied or otherwise. I’ll help you where I can but legally you’re on your own.

Credits and Thanks

I welcome any constructive feedback on this HOWTO and any general software licencing issues, although my opinions are just that: a subjective view. You should understand what each licence means before committing to one for your own software or documentation..

Licence

This document is copyright 2000, 2001 Stephen Darlington. You may use, disseminate and reproduce it freely, provided you:

  • Do not omit or alter this copyright notice.
  • Do not omit or alter the version number and date.
  • Do not omit or alter the document’s pointer to the current WWW version.
  • Clearly mark any condensed, altered or versions as such.

These restrictions are intended to protect potential readers from stale or mangled versions. If you think you have a good case for an exception, ask me.

(This copyright notice has been lifted from Eric Raymond’s Distribution HOWTO.)

Overview

Introduction

Until now, you’ve probably never given much thought to software licences. No-one can blame you. They’re usually pages and pages of legalese telling you what you can and can’t do with the CD you just bought. If you actually sat down and read it all, you would probably never agree to it!

Licences, however, are at the heart of what free or open-source software is all about. Let’s take a look at a number of very broad categories of licence.

Commercial software

The first type is the commercial licence, like the one that Microsoft or Lotus might insist you agree with before using their software. The basic premise is that you don’t own the software, you have an agreement with the author that allows you to use it within certain guidelines. As the copyright owner, they can impose whatever restrictions they want. Common conditions include limits on the number of concurrent users, number of copies, and what you can use it for (for example, “non-commercial use” or a ban on reverse engineering).

The emphasis is what you can’t do, and all the power is in their court!

One thing to note, and this will become more relevant later on, is that none of this relates to the cost of the software (or, more properly, the licence). You can get commercial software, such as Microsoft Internet Explorer, for no cost and still be forced to abide by the publishers conditions.

Shareware

The next kind of software, shareware, is sometimes called free, although as we shall see, that’s not correct.

Shareware was started in the early eighties by Jim Button when a few of his friends started passing round some software he’d written and he started getting phone calls asking for support. Eventually he added a request for $10 to the startup screen and shareware was born.

In short, shareware authors allow you to try out their software for free but request payment for continued use. Many of the same restrictions as for commercial software remain, including the limitations on reverse engineering, concurrent use of the full version, etc, stand. Additionally, the “free” downloads are often broken in some way, perhaps limited functionality or splash screens.

Interestingly, Linus Torvalds describes shareware as combining “the worst of commercial software (no source) with the worst of free software (no finishing touches).”

Public Domain software

All the licences we’ve seen until now have been designed to reduce people’s ability to do what they want with the software.

At the opposite extreme is public domain software. This is software that has no copyright and, therefore, no restrictions on its use. You can copy it onto as many machines as you like, reverse engineer it, make modifications and distribute it as you feel fit.

This is the first kind of software that we’re come across that can rightly be called “free.”

Normally, whenever you write something you automatically own the copyright, even if you don’t add an explicit copyright message. For public domain software, the author throws away these rights allowing everybody to do what they like with the software.

Unfortunately, “anything” also includes selling it. Imagine spending a huge amount of time producing your masterpiece, giving it away and then finding that someone else was able to sell it and make their fortune with all your hard work! Worse, people don’t even have to give you credit for your work; they can legally take it, replace their name with yours and distribute it.

This might be why there isn’t a huge amount on public domain software.

At this point it might be worth looking back at free commercial software. Both public domain software and a free piece of commercial software cost the same, but the freedom you’re given to use it varies. A common phrase you hear with free software is “think free speech not free beer.” The difference between public domain and commercial software show the opposite extremes.

Free software

By now it should be clear that there are many different kinds of free software and not all are equal. The version of free that this section relates to is the one promoted by Richard Stallman of the Free Software Foundation.

But first, a little history.

The Free Software Foundation was formed in 1984 when a printer manufacturer refused to give Richard Stallman the source code (the computer instructions required to make a program). It had been leading up to this for some time — the increasing number of non-disclosure agreements, new software that banned sharing of information, etc. — and the printer manufacturer was just the straw that broke the camels back.

Stallman decided that he could not, in clear conscience, sign a non-disclosure agreement or work with a company that restricted his ability to share information. While most people would have given up at this point and gone to work, for obscene amounts of money, for a big company writing proprietary software, Stallman stuck by his principles and decided to make his own operating system, free of the constraints of commercial systems.

The process leading up to this is documented in more detail in Steven Levy’s excellent ‘Hackers.’ You’ll note that Levy calls Stallman ‘the last real hacker.’ Happily he was wrong, otherwise you wouldn’t be reading this!

As we can tell from the background, “free,” in this context, relates not to the initial cost but to freedom. Stallman was unwilling to surrender the right to make modifications or improvements to any software he used — and to do this you need the source code.

This may sound just like public domain software up to this point. The difference is that there are clauses in the licence that attempt to keep the software free no matter what changes are made. The most famous free software, Linux, uses the most famous free software licence, the GNU General Public Licence. It is sometimes also called Copyleft, as it very cleverly uses the current copyright laws to do the exact opposite of its original mandate.

The way it does this is by insisting that the code and anything derived from it is also released with the GPL licence. In some senses it is ‘viral’ in nature and it is this that is central to many people’s objections.

Also, it’s worth noting that the word ‘derived’ is a little too vague. Does a library linked to a GPL’d program need to be GPL’d also? Does a program running on a free operating system need to be GPL’d?

There’s no clear, obvious answer for either of these with the current version of the GPL. The new version (3) is intended to fix some of these shortcomings, but it’s viral nature will remain.

Open Source software

Open Source software is, in many ways, exactly the same as free software, despite what Richard Stallman says!

It was started in 1997 by Eric Raymond and Bruce Perens as a response to the increasing confusion over the use of the word “free” in relation to software. (Confusion that has continued, or I wouldn’t be writing this document!)

In essence, Open Source is a marketing or PR exercise to make free software more acceptable, more understood by the general public and the big corporates that, until that point, were comforted by the money they had to pay to get commercial software.

Like “free” software, the “Open Source” trade-mark does not mandate a single licence. (Freedom of choice is important, even when it comes to giving away software!) Technically any licence that meets all the requirements in the Open Source Definition can be termed Open Source. These, in summary, are no restrictions on the use of the software, access to the source code and the freedom to make modifications and distribute them.

The two most famous are the Berkeley System Distribution (BSD) Licence, which allows distribution without the source code, and the GNU General Public Licence, although there are many more.

The Sun Community Source Licence, for example, is not compliant because Sun Microsystems demand a fee for any commercial distribution and insists that derivations are still compatible in some arbitrary ways. (This is not intended to single out the SCSL as being particularly bad. However, the fact that it purports to be “open” when it isn’t is a disturbing trend.)

The implications

Overview

Free software has already had a significant effect on the computer industry. Free software is behind most of the critical parts of the Internet, it was used (unsuccessfully) as part of the defense in the Microsoft anti-trust trial and the spate of recent IPO’s has shown that there’s money too.

Unless you bought some shares, this all appears to be affecting other people. There is an impact, however.

I just use software, how does this all affect me?

It’s tempting to think that, if you’re not a ‘techie’ or a hacker, the difference between free commercial, public domain and Open Source software is minimal. But that’s not true, even as a user the difference affects you because the development of the software is affected.

I’ll outline a plausible scenario as an example.

Company X designs and releases a fantastic piece of software. It’s commercial software, but the publisher seems receptive to new ideas, indeed versions 1.1 and 2.0 are exactly what you were looking for and the upgrade costs were reasonable.

At this point any number of things can happen. Perhaps you find a bug in it, one critical to your business. But the publisher offers no warranty for the software and say they are not sure whether they will fix it. (Note that just because you paid for the software, you do not necessarily get better service or a guarantee of any kind. According to the licence, you can’t sue Company X if the software is not fit for the purpose it was sold for.)

Or maybe they go out of business. Or perhaps they start competing with your company and won’t sell you the next version. Or perhaps the features you want are not in the new version. There are a huge number of ‘if’s and ‘maybe’s, all outside your control.

Basically, if you use commercial, close-source software you are at the whim of the publisher. If they do something you don’t like, tough.

However, if you’d used Open Source software you’d have access to the source code and could fix or upgrade the program as you saw fit. And if you couldn’t do it, there are many programmers willing to support the new versions or you could hire someone to do it for you. In summary, you have much more control over future development of the product.

You’ll note that none of the advantages here are strictly related to cost. I think that’s something that people tend to focus on too much, possible due to the “free software” title. However, there are still advantages.

But first we need to get away from the initial cost of the software as that’s normally a small percentage of the total cost. Instead, let’s think in terms of support costs. Once you’ve installed the software, what costs are there? An obvious cost is that of upgrades. Less obvious is lost productivity due to software failure and support charges from the manufacturer.

In the case of free software, there are no upgrade costs (other than the time and inconvenience of doing it, which also applies to commercial software). Free software is usually regarded as more reliable then commercial software — see Fuzz Revisited for more information. And the support charges are optional: you can either deal with it in-house or hire any one of a number of support organisations.

I’m a developer. How does this affect me?

As a developer, you’ll already know the benefits of being able to access the source code for a program. You can fix it, see how it works and integrate bits of it into your new program. (Using parts of another program, however, isn’t quite that simple and is dependent on the licence of the original software.)

A common problem developers see is the loss of their livelihood. If everyone gives away their software, how can anyone make money? It’s a fair question and there’s no single, correct answer.

Perhaps the most common answer is that most software is developed in-house and is not distributed. None of this development will be affected, so if you have that kind of job you can rely on your salary for a while yet!

If you work for a consultancy, almost all the revenue comes not from selling software but from “professional services,” i.e., they charge for developing the software rather than the licence to use it. Again your job is safe.

Then there’s shrink-wrapped software. The Free Software Foundation would say that it should be free. So if you listen to them and you work for Microsoft your job is in danger unless they diversify into services.

The Open Source people would say that there’s nothing wrong with shrink-wrapped software, but point out that there are advantages in releasing the source.

As you can probably see, the risk to your jobs is small and there are many benefits. At least that’s the way I see it and I work writing software!

Where can I read more?

The most obvious place to read more is at the GNU website, after all they started it all.

But there are alternatives. Other important web-sites are as follows:

  • Open Source. This is the ‘official’ Open Source page. There’s lots of interesting stuff here, including a more detailed discussion on the effect of free software on different people Microsoft’s Halloween documents, their unofficial response to the Linux threat.
  • Eric Raymond’s web-site. Eric has written much about Open Source software, with much more depth and style than I can muster!
  • Slashdot. There aren’t more ‘HOWTO’s here, but Slashdot is a community of people interested in Open Source software. The discussions sometimes get childish, but you can learn a lot!

There are also a few books published (at least partially) on the subject:

  • OpenSources. Voices from the Open Source Revolution.. This book talks about all aspects of the Open Source community, including licencing. The main reference is Bruce Perens essay.
  • The Cathedral and the Bazaar. Again, this book is about general Open Source issues, but it includes a discussion on some of the non-obvious implications of the licences, particularly the reason why just because you can, you don’t frequently get many versions of a piece of software.
  • Hackers Steven Levy talks about the early days of the hacker community, including a good piece on Richard Stallman.
Opinion

Death March

Introduction

Perhaps more than any other engineering discipline (see Steve McConnell’s After The Gold Rush), software engineers work on projects that have no real chance of success. There are as many reasons why as there are projects, but if you want to be in with a chance of surviving such a ‘death march’ this could be the book for you.

Content

Edward Yourdon is a well known and well respected computer scientist, so what useful information can he give you in these circumstances? Surely you’re lumbered with the simple choice between putting up with it or resigning?

Well, no. The book explains that there are any number of things to do, and not just for the project stake-holders. There are things that just about anyone on the project — and indeed just outside the project — can do. And quitting is almost always one of the options he gives. I find this interesting because most books tend to argue that you can fix anything. Sometimes you just don’t have the authority to do anything that would make a significant enough change.

Of course, it’s a two-hundred page book, so it doesn’t just launch into this resign-or-fix discussion. First he talks about what a Death March project actually is, and then moves on to finding who the key players in the project are. These people are not always those that you think should be in charge! For example, the CEO’s golfing partner is often in a position of power and influence, although you won’t find them in the organisation chart. (I’ve seen these kind of dynamics in play, but I hadn’t really though about it in these terms.)

He then moves on to negotiating the best deal for you and your team in this bad situation. You may not be able to get your boss to accept a rational argument at the beginning (or even towards the end) of the project, but you should at least try. And these are the arguments to use!

Motivation, both from the various clients and in your own team, play an important role in the success or otherwise of the project, and are discussed in some detail. One vaguely controversial statement is that we all need to be involved in politics to some extent. I agree with the ‘why’ — even your boss may secretly want your project to fail — but I don’t know how. Many, maybe most, of the developers I know have absolutely no interest in politics and try to pretend that it doesn’t affect them!

The next two chapters talk about methodologies and tools, and their applicability to death march projects. The last chapter discusses integrating the death march into your companies culture (most of your projects are going to be like that anyway, so you may as well get used to it!).

Controvacy!

It’s not all good news, though. Some of the chapter on staff motivation is hard going (or at least would be for the people on your project). One of Yourdon’s correspondents suggests that, on a death march project, people should be putting in at least 60 hours a week! I know that some people do that, and that it is encouraged at some companies, but I really don’t think that people should be encouraged to do that on a regular basis. It’s only fair to say that Yourdon goes on to say that people working over 60 hours a week need to be watched closely, but by then the damage may already have been done.

Generally, however, the advice given is very pragmatic. I’d like to think that most of it was obvious, but it isn’t. This is the kind of information you probably realise only after years in the business.

Overall

I’m sure you can guess by now: I’m impressed. Most Computer Science books are not this sensible and are frequently based in research in university labs rather than commerce. In fact, I’m pretty certain that I’ve never seen a book that recommends that you resign in certain circumstances!

It’s not just the detail that makes this an important book. Yourdon backs up his assertions with examples and email’s from colleagues that discuss some of the options available.

If you work in IT, sooner or later you will end up working on a Death-March project. This book is just what you need to be able to tell what chance of success it has and whether you and your organisation will survive it. Highly recommended.

Details

ISBN: 0-13-014659-5

Price: $16.99

Buy this book from Amazon.com or Amazon.co.uk.