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...And measure every wand'ring planet's course
Still climbing after knowledge infinite
 
                Christopher Marlowe (1564 - 1593)

      English Dramatist
     
from The Conquests of Tambourlaine

              

ACM DL Author-ize serviceThe business of software: zeppelins and jet planes: a metaphor for modern software projects
Phillip Armour
Communications of the ACM, 2001
 


 

 

 The Zeppelin Critical Success Factors: Measurement and Control...       

The Zeppelin was the first real bomber, the first real long-distance aerial weapon of war.  But it wasn't a particularly good one.  It was a large, slow-moving bag of highly combustible gas that floated serenely over a war zone.  It had a maximum speed of around 84 mph, a ceiling of 10,000 feet, it could carry perhaps 5,000 lbs of bombs, and you could bring it down with a dart.  An odd weapon, yet at one time, the Zeppelin was the most effective aerial bombardment machine on the planet.

What would it take to shoot down a Zeppelin with a ballistic cannon?  Well, first one would have to measure as many attributes of the system as you could: the velocity of the Zeppelin, its altitude, its distance downrange, its azimuth.  Then you would need to measure much concerning the gun: its muzzle velocity, the shape of charge, the weight and air resistance of the projectile.  Then you would need to measure the air characteristics: viscosity and density, temperature, wind speed, etc.

Once all the measurements are taken as accurately as possible, we can reasonably guarantee to be able to shoot down the Zeppelin, assuming we have a gun that can shoot that far.

Critical (Zeppelin) Success Factors:                                               

  •  Measurement--the precision and accuracy of measuring the factors listed above

  •  Control--the ability to control the system (the gun) according to the measurements

 


  The Jet Plane Critical Success Factors: Agility and Speed...           

We stopped shooting down Zeppelins nearly ninety years ago.  Today we try to shoot down low-flying, very fast, fighter-bombers.  We probably wouldn't even try to use ballistic ordinance for this task.  We'd more likely use a guided missile of some sort.  Some questions:

  •  When we launch a surface-to-air missile do we know where in space it will intercept the plane?                              Answer: no.

  •  If we took more/better measurements before we launched the missile, could we calculate where they will collide?    Answer: no.

  •  Do we need to know where in space the missile will intercept the plane in order to be successful?                          Answer: no.

In this system, the interception of the plane by the missile is non-deterministic.  The ability of this system to achieve success is a function of the flexibility of the system, not of the measurement.

Critical (Jet Plane) Success Factors:                                       

  •  Agility--the missile must be highly responsive to changes in the target

  •  Speed--the missile must simply be fast enough to catch the plane, otherwise it will just outrun the missile

  Old Projects = Zeppelins, New Projects = Jet Planes                   

    Here is the analogy. 

  •  Zeppelins = the "old" projects of twenty years ago: big, ol' lumbering mainframe systems, internal payroll application, 250 COBOL programmers.  These projects were (relatively) highly deterministic, and success was determined by our ability to measure and control.
     

  •  Jet planes are the new projects of today: fast, short window of opportunity, rapid cycle, whose success is determined by the speed and flexibility of the team attempting to hit the target.

 Building Jet Plane Systems using Zeppelin Processes           

The trouble is, many of our processes were developed during the Zeppelin era, and they are anti-Zeppelin processes.  They just don't work very well against the jet plane project targets of today.

 

Zeppelins and Jet Planes...