diff --git a/Archive/Tar.php b/Archive/Tar.php
index 03daa39..bb50ea1 100644
--- a/Archive/Tar.php
+++ b/Archive/Tar.php
@@ -244,7 +244,7 @@ public function __construct($p_tarname, $p_compress = null, $buffer_length = 512
                 "a8checksum/a1typeflag/a100link/a6magic/a2version/" .
                 "a32uname/a32gname/a8devmajor/a8devminor/a131prefix";
         } else {
-            $this->_fmt = "Z100filename/Z8mode/Z8uid/Z8gid/Z12size/Z12mtime/" .
+            $this->_fmt = "Z100filename/Z8mode/Z8uid/Z8gid/a12size/Z12mtime/" .
                 "Z8checksum/Z1typeflag/Z100link/Z6magic/Z2version/" .
                 "Z32uname/Z32gname/Z8devmajor/Z8devminor/Z131prefix";
         }
diff --git a/tests/big.phpt b/tests/big.phpt
new file mode 100644
index 0000000..ad5f9c7
--- /dev/null
+++ b/tests/big.phpt
@@ -0,0 +1,21 @@
+--TEST--
+tests if files > 8G are supported
+--SKIPIF--
+--FILE--
+<?php
+require_once dirname(__FILE__) . '/setup.php.inc';
+$tar = new Archive_Tar(dirname(__FILE__) . '/big.tar.bz2');
+$content = $tar->listContent();
+$found_big_file = false;
+foreach ($content as $item) {
+  if ($item['filename'] === 'big_archive/8.5G_file') {
+    $found_big_file = true;
+    $phpunit->assertEquals(9126805504, $item['size'], 'size of big file correct');
+  }
+}
+$phpunit->assertTrue($found_big_file, 'found the big file in the archive');
+echo 'tests done';
+?>
+--CLEAN--
+--EXPECT--
+tests done
diff --git a/tests/big.tar.bz2 b/tests/big.tar.bz2
new file mode 100644
index 0000000..ec443f1
Binary files /dev/null and b/tests/big.tar.bz2 differ