The wiki (or Hadoop The Definitive Guide) are good ressources.

Mapper is the name of the abstract class/interface. It does not really make
sense to talk about number of mappers.
A task is a jvm that can be launched only if there is a free slot ie for a
given slot, at a given time, there will be at maximum only a single task.
During the task, the configured Mapper will be instantiated.

Always :
Number of input splits = no. of map tasks

And generally :
number of hdfs blocks = number of input splits



PS : I don't know if it is only my client, but avoid red when writting a

On Tue, Feb 25, 2014 at 8:49 AM, Dieter De Witte <[EMAIL PROTECTED]> wrote:
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