code: public function formatMemorySize($size, $precision = 2)
      {
          $sizes = array(" Bytes", " KB", " MB", " GB", " TB", " PB", " EB", " ZB", " YB");
          if ($size == 0) {
              return $this->__('n/a');
          } else {
              $value = round($size / pow(1000, ($i = floor(log($size, 1000)))), $precision);
              $unitIndex = (int)$i;
              return $this->__('%s%s', $this->formatNumber($value, $precision), $sizes[$unitIndex]);
          }
      }
docs: Returns readable file size
  
  @param int $size size in bytes
  @param int $precision
  @return string