my @ary = splice(@srcfiles,0,1024);
my $ret = system("tar -cvf $tar_file @ary") # tar only, no update on 'z'
    and die "Couldn't create tarfile '$tar_file': $!\n";

while(@ary = splice(@srcfiles,0,1024)) {
    $ret = system("tar -uvf $tar_file @ary");
        and die "Couldn't update '$tar_file': $!\n";
}