Yes, that is the problem.

   DB<27> x $start
 0  0.6
   DB<28> x $store->[3]
 0  0.6
   DB<29> x 0.6 == $start
 0  ''
[download]

Update: So we all can take part in the fun:

  DB<1> $x=0.6
  DB<2> x ($l,$h)=unpack"L*",pack"d",$x
0  858993459
1  1071854387
  DB<3> x $y=unpack"d",pack"L*",$l+1,$h
0  0.6
  DB<4> x $z=unpack"d",pack"L*",$l-1,$h
0  0.6
  DB<5> x $y-$x
0  '1.11022302462516e-016'
  DB<6> x $x-$z
0  '1.11022302462516e-016'
  DB<7> x $y-$z
0  '2.22044604925031e-016'
  DB<8> x unpack"d",pack"L*",$l-4,$h
0  0.6
  DB<9> x unpack"d",pack"L*",$l-5,$h
0  0.599999999999999
  DB<10> x unpack"d",pack"L*",$l+4,$h
0  0.6
  DB<11> x unpack"d",pack"L*",$l+5,$h
0  0.600000000000001
[download]

merlyn, tye and tilly (in CB): thanks a lot. tye especially thanks for the warm welcome ;-). Your debug-lines clear up a lot, I must say.

This whole thread is a nice example of a testing procedure gone that evokes it's own problems. My real-world data will, by definition, never repeat. Accidently, some datapoints may have an exact interval of one second, but that chance will be neglectable. (1 out of 1000 or less, I estimate)

I will be on guard for the floating point arrhythmic from now on.

Jeroen
"We are not alone"(FZ)