my %comp_patch;  # will be a hash of arrays
my $comp_name;   # will store most recently seen computer name

open( C, "<", "One.log" ) or die "One.log: $!";
while (<C>) {
    chomp;
    if ( /^KB\d+/ ) { # this is a patch name
        if ( not exists( $patch_id{$_} )) {
            warn "Computer $comp_name has unknown patch: $_\n";
            next;  # (might want to do something else here)
        }
        $comp_patch{$comp_name}[$patch_id{$_}] = $_;
    }
    elsif ( /^\S+/ ) { # not a patch name, must be a computer name
        $comp_name = $_;
    }
}