device_dir = W1Util::concat_paths(base_dir, device_id);
device_ch_dir = W1Util::concat_paths(base_dir, "cache");
device_ch_dir = W1Util::concat_paths(device_ch_dir, device_id);
device_dir = W1Util::concat_paths(base_dir, device_id);
device_ch_dir = W1Util::concat_paths(base_dir, "cache");
device_ch_dir = W1Util::concat_paths(device_ch_dir, device_id);