Another space tourist - so what?

I've just read about Guy Laliberté's Poetic Social Mission for the One Drop Foundation. The seventh private space traveller is doing more with his once-in-a-lifetime opportunity than just enjoying himself - he plans to stage a worldwide music and arts event involving himself aboard the ISS, to draw attention to the worldwide need for fair and equitable access to water.

The guest list sounds brilliant (Peter Gabriel, U2, Shakira and many others) - the downside is that the two-hour spectacular is due to kick off at 8pm Eastern on October 9th, which makes it about 1am in our time zone. I think it's being broadcast via YouTube, so perhaps we'll be able to watch it later on? Details about this are a bit sketchy at the moment - the site just says "broadcast right here".

Save Bletchley Park with Boffoonery!

The title says it all really.

Jason Gorman has managed to get some amazing events off the ground in the past couple of years and this one should be absolutely excellent. It's called Boffoonery! ("buffoonery for boffins") - a once-only comedy benefit gig to raise money for the extremely important wartime heritage site (Station X) and unique computing museum that is Bletchley Park near Milton Keynes.

Jason's partners in crime are comedy writer James Cary, whose credits include hit TV comedies like My Hero and My Family and who also writes the cult BBC Radio 4 sitcom Hut 33, which is set at Bletchley Park, and veteran TV and radio comedy producer David Tyler.

The show is still taking shape, but Jason is delighted to be able to confirm that Robert Llewellyn (Red Dwarf), Richard Herring (Fist Of Fun, This Morning With Richard Not Judy) and cerebral stand-up Robin Ince are on the bill. More big name comedians and comedy writers are TBA, so keep en eye out for updates.

The best way we can support Bletchley Park is to send a message to government and funding bodies about how much we care. If the show were to sell out, and sell out quickly, that would send a very clear message indeed.

And since you ask - yes, you can help. Tickets go on sale on Wednesday Aug 12th at 9am. Please help to spread the word and create a splash on Wednesday. Here are some of the ways you can help:

• Buy your tickets on Aug 12th
• Tell your friends and colleagues about Boffoonery!, and encourage them to buy their tickets on Aug 12th
• Print off copies of the show's A4 poster, which you can download from www.boffoonery.com, and stick them up on your noticeboards at work
• Blog about Boffoonery, and pass on these suggestions about how people can help save Bletchley Park
• If you're a Twitter user, on the morning of Aug 12th send a tweet about #boffoonery and www.boffoonery.com, and RT any #boffoonery tweets that cross your path

It's going to be brilliant evening, and your kindness and generosity will ensure that generations to come will be able to see and experience the achievements of those brilliant boffins whose ingenuity saved 22 million lives and ushered in the information age.

You can find out more by visiting www.boffoonery.com, or following #boffoonery on Twitter or "boffoonery" on Facebook.

A pity there isn't a theatre big enough in Bletchley Park itself to host this event! That said, the Bloomsbury Theatre is easier for me to get to...

Don't forget: tickets go on sale on 12th August 2009 at 9am and the show takes place on Tuesday Nov 3rd.

PS other efforts to support the National Museum of Computing at Bletchley Park include this amazing URL Shortener called Station X. Keep up the good work, guys!

Gimme Shelter

A friend has been made homeless - as a result of a bout of illness, he got behind with his rent payments. One morning his landlord just turned up with a heavy friend and dumped him and most of his belongings outside without a key.

While this is clearly an illegal eviction (the landlord should have taken the court route), my friend is unable to defend himself because he's still not well and besides, he's sure that no-one will believe his version of events. Well, it is fairly monstrous.

Today he rang Shelter to try to obtain help (having already had a pretty hopeless interview with the emergency housing office in his borough - they took the attitude that since he didn't have a court order evicting him, he must have made himself intentionally homeless). He reports that he got an answerphone message that began "Welcome to Shelter. Please note that we cannot provide accommodation..."

Well, what on Earth is Shelter for then?

I am also disappointed that The Salvation Army was unwilling to help him - I have been supporting it with a regular monthly donation for years as I was under the impression that it provided help to the homeless.

Passwords passé?

I've just read a highly amusing and (for Twitter) embarrassing story about the loss of confidential information stored by a Twitter staffer under Google Apps.

The article closes by trotting out the usual advice about making usernames and passwords secure - make them long and cryptic, don't use the same credentials for more than one service, and don't write them down. However, I heard a piece on BBC Radio 4 not long ago in which Damian Grammaticus investigated computer security and hacking. It showed that any Windows password under 14 characters long could be cracked in seconds, regardless of how many punctuation characters and digits it contained. Since we're all forced to register with dozens, if not hundreds of different IT services on the Internet and our employers' networks, it simply isn't possible for standard-issue mortals to memorise that many cryptic usernames and passwords (particularly where IT policy demands that the password be changed regularly).

Common approaches to overcome these wetware limitations include

• Writing usernames and passwords down - not recommended because anyone could find them and steal your precious secret information
• Using a standard username and password for many different sites - again not recommended because if a thief finds out one valid combination, (s)he can access all your accounts
• Generating usernames and passwords by means of some function, which you can compute mentally without too much effort and which preferably takes the current month and/or the URL of the service as parameters - this works OK in certain situations, but because the algorithm can't be terribly complicated, someone could reverse-engineer it and have access to all your accounts
• Using a password manager application: something that you install on your laptop (say) and which stores all your usernames and passwords for you, encrypted of course, so that you can only gain access using a master password or even biometric authentication - disadvantages may include the risk of losing the device or the master access key, as well as the inconvenience of having to have the device to hand whenever you need one of your account credentials (not to mention the cost of the password manager itself)
• Trusting an Internet service such as DataInherit to manage the keys for you, which has the advantage that should you die or be incapacitated, a nominated person or persons can automatically be given access to selected accounts in your portfolio - disadvantages include the price and the number of steps you have to go through to retrieve any given username and password

Surely the time is ripe for a security architecture that fully separates authentication from authorisation. Depending on your spending power and level of paranoia, you could procure authentication services from any reputable trust authority of your choosing, which could make use of a single very secure identifier and pass phrase, optionally combined with more stringent authentication factors such as digital certificates, RSA SecurID devices, or even biometrics. The identity thus established would be securely and trustworthily conveyed to whatever service you were trying to access - regardless of whether it is on a company intranet, the public Internet or your ATM network.

Unfortunately the Twitters and Googles of this world, not to mention the myriad online shopping sites, still want you to register with them directly and not with some third-party authentication provider. This is because they believe that there's value in knowing your real world (meatspace) name and address, age, marital status and what have you so that they can push targeted marketing at you. It doesn't seem to bother them that the majority of the data thus gathered is probably untrue, because most Internet users are paranoid about giving away such information.

I want single sign-on to be ubiquitous, effortless, virtually unhackable and foolproof (as well as heritable, as directed by me, when I leave this world, so that my digital assets are not locked away forever). By "ubiquitous", I mean that I should be able to use the same sign-on for my employer's network as for any client's network which wants to authorise me to access some selection of their IT services, for Internet services on which I register and preferably at the bank's ATM too. By "effortless", I mean that authenticating myself to all these services is necessary only once per computer per day and ideally doesn't require me to memorise anything, or at most one thing. A physical token in addition, or a biometric, would be acceptable.

The theoretical foundations already exist, underpinning such standards as Kerberos and WS-Trust. But to make it work in the real world of competing and highly disparate IT services, the community of service providers would need to discover some kind of shared interest in implementing it as standard. A grand computing challenge for the new millennium, perhaps?

Test-Driven Design is not testing

I've recently worked with a team doing its first agile project (though one or two team members had been involved in an agile project before). The most difficult concept to get across was TDD - test driven design. I found that people really didn't grok the idea until I pair-programmed with them for a couple of hours. I wonder why that might be.

Dan North has suggested one possibility. He observed that newcomers to TDD often don't get the really big payback because they continue to think that TDD is mainly about testing - even if they will admit that writing the tests before the code leads to better quality code. They never transition to treating TDD as a design process, letting them discover the API to a component they're writing, nor to the realisation that TDD is about defining the behaviour of their component and its interactions with other components of the system.

Keith Braithwaite has put forward another consideration. In physical engineering disciplines, practitioners speed up their work process by using gauges. There are many kinds, from the simple spark plug gap gauge, which is simply a sliver of metal to slide between the electrodes, to electronic vernier calliper gauges that can be pre-set to a precise dimension with tolerances above and below. Each workpiece is tested at each stage of the process by checking its dimensions with the appropriate gauge(s). Workpieces that are out of tolerance are sent back for rework or scrapped. Our unit tests are a bit like that - they provide a safeguard that the software component we're working on still meets all its requirements following any engineering we've done.

It occurred to me today that unit and acceptance tests, particularly if automated, perform another valuable function in the context of an agile (especially a lean) development process. Whereas the waterfall processes familiar to most developers are characterised by "quality gates" at key stages, every single artifact in an agile development has its own little quality gate, manifested in the appropriate tests. This theoretically frees the development process from the usual bottlenecks that the quality gates tend to become.

I say "theoretically", because in many instances agile development projects have to take place within a quality system that doesn't take advantage of incremental delivery. Instead, continued approval and in many cases funding for the project tends to be contingent on passing the traditional quality gates following requirements analysis, functional specification, high-level design, low-level design, coding, integration, system test and acceptance. Project managers are therefore forced to conjure up some kind of spurious linkage between the milestones laid down in the rigid quality system and some arbitrary points along their product release plan. This can hamper their freedom to adjust the release plan in response to changing circumstances and emerging technical insights.

This could be avoided if the quality system could recognise that properly written tests represent every work product of a software development project apart from the code itself. It should therefore simply insist on a verification at each iteration (or at each release, perhaps) that the tests comprehensively and comprehensibly represent the requirements of the business on the system under development and that the required set of tests pass repeatably. I say "the required set" because there's always the possibility that some tests will intentionally fail - e.g. where they have been written to test features that are not yet in the current release.

In other words, TDD can be used to eliminate the quality-gate bottlenecks of quality systems that assume waterfall development processes.

24th March 2009: Theory of Constraints Challenged

My sincere thanks to Kevin Rutherford and Allan Kelly for co-presenting a fascinating session about lean software development to the BCS Kingston & Croydon branch on 24th March this year, entitled "Lean, Constraints, Action!". The audience was excellent too and helped us re-create a famous experiment related by Eliyahu Goldratt in "The Goal".



(Click images to see a larger version)

I had participated in this game previously at the London XP Day 2008 (facilitated by Karl Scotland in an Open Space session). It is designed to demonstrate an intuitively paradoxical finding: that a lean, pull-oriented flow substantially reduces the amount of inventory or work in progress (WIP), while improving throughput.

However, I had a sneaky feeling that the experiment was biased, because in the first "push" simulation, the assembly line was not pre-loaded with WIP, while in the second "pull" simulation, the line was pre-loaded with workpieces at each "workstation's" input buffer up to either the maximum limit or to 50% of that limit. Therefore in a simulation of 10 rounds (equivalent to ten working days - approximately equal to the average cycle time in a six-workstation setup) the push simulation will only start to produce output towards the very end of the simulation, while the pull simulation will produce something from the very first day.



So I got Allan and Kevin to agree to vary the rules a little bit, to try to get closer to a "steady state" from the first "day". Before each of the two simulations, our teams placed three Lego blocks on each of the coasters representing the input buffers of the second through sixth workstations (the first workstation of course has the whole of the product backlog as its input hopper). In fact, as it turned out, four workpieces would have been closer to the true steady state in the pull simulation, even more in the push simulation.

Off our teams went and played the production line for ten rounds each. In the push simulation, the die was passed in order from workstation 1 to workstation 6 during each round and the number of workpieces transferred to the next input buffer was the number thrown, up to the number of pieces available in the workstation's input buffer. Instances of starvation were rare under this system, but did occur sometimes. At the end we counted up the number of pieces that had come off the end of the line and the number currently in progress (i.e. on any of the five input buffers for workstations 2 to 6).

In the pull simulation, the die was passed in the opposite direction and the input buffers were constrained to a maximum of six workpieces. So if the next input buffer had three pieces already in it and the player threw anything over a 3, they could only pass along 3 more workpieces (subject to their own input buffer holding at least 3, of course). Once again, the results after 10 rounds were compared.

The results didn't surprise me particularly, but I think some of the others were a little taken aback:



As you can see, the constraint resulted in both lower WIP and lower throughput. This makes sense when you consider that there were far more occasions during the pull game than during the push game when players were unable to process the full number of workpieces indicated by the die.

Looking back at the game notes, it is noted that if the simulation is run for much longer than 10 days, the pull (or Kanban) system "will rarely produce as much as the traditional push". This may have escaped the attention of some readers (or perhaps it's a more recent edit - I don't know).



My conclusion is that you get nothing for free. The cost of reducing WIP is reduced throughput, which is perfectly acceptable as long as you're aware of it. Software development projects are not production lines in any case, so it is very unlikely that any developer will sit around kicking her or his heels if the work runs out on a given day. There are always low priority tasks such as fettling the build system, cleaning up the documentation on the project Wiki, answering user support requests etc. - or just take the next item off the product backlog and raise the kanban limit temporarily.

Distributed bug-tracking in Haskell

At the recent SPA 2009 conference, there was a lot of talk about functional programming, Haskell in particular (a couple of years ago, the flavour of the month had been Erlang). Just to prove that Haskell is no longer "just a research language", along comes DisTract, a distributed issue-tracking system that runs in Firefox browsers. If you're already using Git, Darcs, Mercurial or Monotone as your distributed software configuration management solution, the author reasoned, why shouldn't you be able to close bugs while you're off-line at the same time as you check in your fix? Caveat: I have not tried this yet, but it sounds like a really neat idea. Does anyone know of a user forum?