Updated - see end of story

REAL coffee. Mmmmmm. Ever since we started running courses here, we've provided customers with superb coffee. Grind the beans as required, brew the coffee with freshly heated pure water and supply a choice of sugars and sweeteners for those who want such things.

Our first coffee machine had a water capacity enough to make 4 mugs of coffee. Beans had to be replenished every 10 mugs or so, and the coffee grounds cleared out about once in every 7. The drip tray needed to be emptied every 12.

Ever come across MTBF - "Mean Time Between Failure" calculations? You take the reciprocal of the sum of the reciprocals of each component failure frequency to calculate your overall failure frequency. Of in our example:

earth-wind-and-fire:~ grahamellis$ perl
print 1/( 1/4 + 1/10 + 1/7 + 1/12 )
1.73553719008264
earth-wind-and-fire:~ grahamellis$

This coffee machine needed servicing more frequently than every two mugs

Our current coffee machine is a commercial machine "That looks like it's suitable for a small but classy cafe" said my son Chris when he visited last weekend and he's right - it came with a table showing numbers of cups of coffee served daily, and prices we could charge, to make certain amounts of money. That bit's irellevant to us since we don't charge customers for coffee - it's free and available whenever it's wanted - but it just shows you.

The capacities of the new machine are much higher, but perhaps not as high as you might think. But that give us a new opportunity. It's called "preventitive maintainance" in the jargon of this article and it means that we can service the coffee machine overnight, and between coffee breaks, and be reassured that it's not going to be forever demanding attention.

Updated with the opening of our new training centre at Well House Manor .... We've installed a new coffee machine that's plumbed in to the mains, that has its own drain, and dumps its grounds into an enormous bin. The coffee hoppers are large too so we're a step further improved!

But the MTBF calculation is an excellent example, and so I've written another example - this time for use on our Ruby course which shows how operator overloading can be done in that language. The source code of the example is available on line, of course!
(written 2005-01-20, updated 2006-12-03)

 G205 - Well House Consultants - Food and Drink.
  [3387] Eating out in Melksham - where we like for lunch. - (2011-08-11)
  [3233] C / C++ Course Lunch - sitting out at the West End - (2011-04-07)
  [3199] Lunch for Melksham Businesses - (2011-03-11)
  [3182] What we look for in a lunchtime cafe restaurant in Melksham - (2011-02-24)
  [2784] Course Lunches - (2010-05-27)
  [2591] Melksham Hotel, B and B or business accommodation? - (2010-01-20)
  [2590] A healthy, local breakfast in Melksham - (2010-01-19)
  [1904] Ruby, Perl, Linux, MySQL - some training notes - (2008-11-23)
  [1843] How many cups of coffee? - (2008-10-17)
  [1332] Melksham Hotel - Five Star Kitchen! - (2007-09-04)
  [456] Laying out a vegetarian lunch - (2005-10-05)
  [302] Dining full circle - (2005-05-06)
  [221] Lunchtime Drink - (2005-02-20)
  [211] Look after your staff and they'll look after you. AOL. - (2005-02-12)
  [207] Canteen Dragon - (2005-02-09)
  [36] Tesco at 5 - (2004-09-02)

P202 - Perl Fundamentals
  [3574] Perl functions such as chop change their input parameters - (2012-01-10)
  [3542] What order are operations performed in, in a Perl expression? - (2011-12-07)
  [3398] Perl - making best use of the flexibility, but also using good coding standards - (2011-08-19)
  [3329] Perl from basics - (2011-06-20)
  [3278] Do I need to initialise variables - programming in C, C++, Perl, PHP, Python, Ruby or Java. - (2011-05-05)
  [3102] AND and OR operators - what is the difference between logical and bitwise varieties? - (2010-12-24)
  [3059] Object Orientation in an hour and other Perl Lectures - (2010-11-18)
  [2876] Different perl examples - some corners I rarely explore - (2010-07-18)
  [2832] Are you learning Perl? Some more examples for you! - (2010-06-27)
  [2442] Variable storage - Perl, Tcl and Python compared - (2009-10-08)
  [1946] Variable Types in Perl - (2008-12-15)
  [1826] Perl - Subs, Chop v Chomp, => v , - (2008-10-08)
  [1726] Hot Courses - Perl - (2008-07-28)
  [1448] Question on division (Java) - Also Perl, PHP, Python ... - (2007-11-28)
  [1312] Some one line Perl tips and techniques - (2007-08-21)
  [748] Getting rid of variables after you have finished with them - (2006-06-06)

R108 - Ruby - More Classes and Objects
  [3260] Ruby - a training example that puts many language elements together to demonstrate the whole - (2011-04-23)
  [3158] Ruby training - some fresh examples for string handling applications - (2011-02-05)
  [3154] Changing a class later on - Ruby - (2011-02-02)
  [3142] Private and Public - and things between - (2011-01-22)
  [2980] Ruby - examples of regular expressions, inheritance and polymorphism - (2010-10-02)
  [2977] What is a factory method and why use one? - Example in Ruby - (2010-09-30)
  [2717] The Multiple Inheritance Conundrum, interfaces and mixins - (2010-04-11)
  [2623] Object Oriented Ruby - new examples - (2010-02-03)
  [2620] Direct access to object variable (attributes) in Ruby - (2010-02-02)
  [2616] Defining a static method - Java, Python and Ruby - (2010-02-01)
  [2604] Tips for writing a test program (Ruby / Python / Java) - (2010-01-29)
  [2603] Ruby objects - a primer - (2010-01-29)
  [2601] Ruby - is_a? v instance_of? - what is the difference? - (2010-01-27)
  [2292] Object Orientation in Ruby - intermediate examples - (2009-07-16)
  [1587] Some Ruby programming examples from our course - (2008-03-21)
  [1217] What are factory and singleton classes? - (2007-06-04)
  [656] Think about your design even if you don't use full UML - (2006-03-24)

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