function _getChannelFromAlias($channel)
    {
        if (!$this->_channelExists($channel)) {
            if ($channel == 'pear.php.net') {
                return 'pear.php.net';
            }

            if ($channel == 'pecl.php.net') {
                return 'pecl.php.net';
            }

            if ($channel == 'doc.php.net') {
                return 'doc.php.net';
            }

            if ($channel == '__uri') {
                return '__uri';
            }

            return false;
        }

        $channel = strtolower($channel);
        if (file_exists($this->_getChannelAliasFileName($channel))) {
            // translate an alias to an actual channel
            return implode('', file($this->_getChannelAliasFileName($channel)));
        }

        return $channel;
    }