Why does it take time to write data to disk if there are no changes in files?

Question

linux

Self-built OS on linux kernel 4.8 and busybox.
Lives entirely in the initramfs, the hard drive is connected only for torrents and samba. All temporary files, logs, etc., including the torrent cache, are moved to tmpfs. find <path to hdd mount point> -mmin -<number of minutes since system start+little bit for even number> returns empty. cat /proc/diskstats shows that there are still some writes to the disk (about 5-6 blocks per hour). An ext4 partition, mounted with the -noatime option and journaling disabled.
Question: what and where is written if no file is changed? ctime changes, checked if any file is changed, find displays it.

Answer 1

service areas.
The operating system regularly notes that "everything is fine with the file system, pending writes are fully completed." On Windows it's the same.
It is made so that in case of an incorrect reboot, the operating system is sure that everything is in order and does not check the disk completely, which would take a lot of time.