Shared Memory Tutorial

[Rafael Marco de Lucas]

   Hello,
  can somebody tell me where to find a tutorial about shared memory ?
  i want to write a program that reads many data from disk and keeps it
  in not swapped memory, after when this program receives a signal it
  forks an application that should read an input file and compute something
  using the data from the shared memory,,...
    if you can send me an example or sugesstion about how to do it
  i would thank you a lot,

     best cheers,
                    Rafa