#!/perl/bin/perl
use warnings;
use strict;

sub ping_a_host {
  my $host = shift;
  `ping -n 1 -w 1 $host 2>NUL` =~ /Received = 0/ ? 0 : 1;
}

my %pid_to_host;
my %host_result;

sub wait_for_a_kid {
  my $pid = wait;
  return 0 if $pid < 0;
  my $host = delete $pid_to_host{$pid}
    or warn("Why did I see $pid ($?)\n"), next;
  warn "reaping $pid for $host\n";
  $host_result{$host} = $? ? 0 : 1;
  1;
}

my @hosts = map "10.0.1.$_", "025".."026";

for (@hosts) {
  wait_for_a_kid() if keys %pid_to_host > 10;
  if (my $pid = fork) {
    ## parent does...
    $pid_to_host{$pid} = $_;
    warn "$pid is processing $_\n";
  } else { # child does
    ## child does...
    exit !ping_a_host($_);
  }
}

## final reap:
1 while wait_for_a_kid();

for (sort keys %host_result) {
  print "$_ is ", ($host_result{$_} ? "good" : "bad"), "\n";
}

##</code><code>##

C:\Scripts\Parallel>ping_parallel.pl
-3676 is processing 10.0.1.025
-3072 is processing 10.0.1.026