I wrote a simple backup script which puts all files in his folder (and all of the sub-folders) in one TAR archive...
(It's classic TAR format not USTAR, so filename and path to it can't be longer then 99 chars)
<?php
/***********************************************************
 * Title: Classic-TAR based backup script v0.0.1-dev
 **********************************************************/
Class Tar_by_Vladson {
 var $tar_file;
 var $fp;
 function Tar_by_Vladson($tar_file='backup.tar') {
 $this->tar_file = $tar_file;
 $this->fp = fopen($this->tar_file, "wb");
 $tree = $this->build_tree();
 $this->process_tree($tree);
 fputs($this->fp, pack("a512", ""));
 fclose($this->fp);
 }
 function build_tree($dir='.'){
 $handle = opendir($dir);
 while(false !== ($readdir = readdir($handle))){
 if($readdir != '.' && $readdir != '..'){
 $path = $dir.'/'.$readdir;
 if (is_file($path)) {
 $output[] = substr($path, 2, strlen($path));
 } elseif (is_dir($path)) {
 $output[] = substr($path, 2, strlen($path)).'/';
 $output = array_merge($output, $this->build_tree($path));
 }
 }
 }
 closedir($handle);
 return $output;
 }
 function process_tree($tree) {
 foreach( $tree as $pathfile ) {
 if (substr($pathfile, -1, 1) == '/') {
 fputs($this->fp, $this->build_header($pathfile));
 } elseif ($pathfile != $this->tar_file) {
 $filesize = filesize($pathfile);
 $block_len = 512*ceil($filesize/512)-$filesize;
 fputs($this->fp, $this->build_header($pathfile));
 fputs($this->fp, file_get_contents($pathfile));
 fputs($this->fp, pack("a".$block_len, ""));
 }
 }
 return true;
 }
 function build_header($pathfile) {
 if ( strlen($pathfile) > 99 ) die('Error');
 $info = stat($pathfile);
 if ( is_dir($pathfile) ) $info[7] = 0;
 $header = pack("a100a8a8a8a12A12a8a1a100a255",
 $pathfile,
 sprintf("%6s ", decoct($info[2])),
 sprintf("%6s ", decoct($info[4])),
 sprintf("%6s ", decoct($info[5])),
 sprintf("%11s ",decoct($info[7])),
 sprintf("%11s", decoct($info[9])),
 sprintf("%8s", " "),
 (is_dir($pathfile) ? "5" : "0"),
 "",
 ""
 );
 clearstatcache();
 $checksum = 0;
 for ($i=0; $i<512; $i++) {
 $checksum += ord(substr($header,$i,1));
 }
 $checksum_data = pack(
 "a8", sprintf("%6s ", decoct($checksum))
 );
 for ($i=0, $j=148; $i<7; $i++, $j++)
 $header[$j] = $checksum_data[$i];
 return $header;
 }
}
header('Content-type: text/plain');
$start_time = array_sum(explode(chr(32), microtime()));
$tar = & new Tar_by_Vladson();
$finish_time = array_sum(explode(chr(32), microtime()));
printf("The time taken: %f seconds", ($finish_time - $start_time));
?>