I have trouble understanding the term "Serializing to memory", why not use "save to memory" ...

I think "save" is more commonly used with nonvolatile storage, while "serialize" is commonly used to mean "transform a data structure to a string (or sequence of bytes)".

Thanks again Corion for the explanation. As allways when learning a module, I made a sample program that uses it, and I understand it better now.

#!/usr/bin/perl
# Hash,use of keys and values inc. use Storable
use strict;
use warnings;
use Data::Dumper qw(Dumper);
use Storable     qw(store retrieve freeze thaw);

my %hash;
my $hash;

sub Dump {
  local $Data::Dumper::Terse    = 1;
  local $Data::Dumper::Purity   = 1;
  local $Data::Dumper::Deepcopy = 1;
  local $Data::Dumper::Indent   = 1;
  local $Data::Dumper::Sortkeys = 1;
  Data::Dumper::Dumper(@_);
}

# presize %hash (to a power of 2)
keys(%hash) = 8;

# create a hash with a list of key/value pairs
%hash = (
  '01' => 'data1',
  '02' => 'data2',
  '03' => 'data3',
  '04' => 'data4',
  '05' => 'data5',
  '06' => 'data6'
);

# store hash  
store \%hash, 'store.txt';

# retrieve hash
$hash = retrieve('store.txt');

# dump hash
print Dump(\%hash);
print "\n";

# freeze creates a binary image of a data structure,
# and thaw takes that image and turns it back into a
# copy of the original data structure.

my $str = freeze \%hash;
printf "Serialization of %%hash is %d bytes long.\n", length($str);
print "\n";

# clone hash
my %table_clone = %{ thaw($str) };

# dump hash
print "This is your clone:\n";
print Dump(\%table_clone);

exit;
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