MTD subsystem (stands for Memory Technology Devices) provides an abstraction layer for raw flash devices. It makes it possible to use the same API when working with different flash types and technologies, e.g. NAND, OneNAND, NOR, AG-AND, ECC'd NOR, etc.
http://www.linux-mtd.infradead.org/doc/general.html
sudo dmesg | grep mtd
[ 2.910229] systemd[1]: Starting Load Kernel Module mtdpstore...
[ 2.946037] mtd device must be supplied (device name is empty)
[ 2.979483] systemd[1]: modprobe@mtdpstore.service: Deactivated successfully.
[ 2.979714] systemd[1]: Finished Load Kernel Module mtdpstore.
systemd-pstore.service - Platform Persistent Storage Archival
Loaded: loaded (/lib/systemd/system/systemd-pstore.service; enabled; vendo>
Active: inactive (dead)
Condition: start condition failed at Tue 2022-09-20 07:06:20 IST; 14min ago
└─ ConditionDirectoryNotEmpty=/sys/fs/pstore was not met
Docs: man:systemd-pstore(8)
Systemd has a systemd-pstore component that scans the pstore on boot and if non-empty, takes all previously created dumps, transfers them into its journal and removes the pstore elements. This is very important on UEFI systems, which only have a limited amount of space for variables.
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1978079
This problem affects (at least) Ubuntu 20.04 and 22.04. A quick fix would be to configure CONFIG_EFI_VARS_PSTORE=y so that it's always available. A long term fix would make systemd rescan the directory after all module probing settled.
computer@computer:~$ uname -r
5.15.0-47-generic
computer@computer:~$ ls /boot
config-5.15.0-46-generic initrd.img memtest86+.bin System.map-5.15.0-47-generic vmlinuz.old
config-5.15.0-47-generic initrd.img-5.15.0-46-generic memtest86+.elf vmlinuz
efi initrd.img-5.15.0-47-generic memtest86+_multiboot.bin vmlinuz-5.15.0-46-generic
grub initrd.img.old System.map-5.15.0-46-generic vmlinuz-5.15.0-47-generic
journalctl -xn
Sep 20 07:30:01 computerx CRON[5108]: pam_unix(cron:session): session opened for user root(uid=0) by (uid=0)
Sep 20 07:30:01 computerx CRON[5109]: (root) CMD ([ -x /etc/init.d/anacron ] && if [ ! -d /run/systemd/system ]; then /usr/sbin/invoke-r>
Sep 20 07:30:01 computerx CRON[5108]: pam_unix(cron:session): session closed for user root
Sep 20 07:30:08 computerx sudo[5112]: computer : TTY=pts/0 ; PWD=/home/computer ; USER=root ; COMMAND=/usr/bin/sh -c echo 1 > /proc/sys/>
Sep 20 07:30:08 computerx sudo[5112]: pam_unix(sudo:session): session opened for user root(uid=0) by (uid=1000)
Sep 20 07:30:08 computerx sudo[5112]: pam_unix(sudo:session): session closed for user root
Sep 20 07:31:09 computerx anacron[5176]: Anacron 2.3 started on 2022-09-20
Sep 20 07:31:09 computerx systemd[1]: Started Run anacron jobs.
░░ Subject: A start job for unit anacron.service has finished successfully
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ A start job for unit anacron.service has finished successfully.
░░
░░ The job identifier is 2557.
Sep 20 07:31:09 computerx anacron[5176]: Normal exit (0 jobs run)
Sep 20 07:31:09 computerx systemd[1]: anacron.service: Deactivated successfully.
░░ Subject: Unit succeeded
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ The unit anacron.service has successfully entered the 'dead' state.
ls -lrt /var/spool/anacron
total 12
-rw------- 1 root root 9 Sep 2 16:28 cron.monthly
-rw------- 1 root root 9 Sep 16 11:18 cron.weekly
-rw------- 1 root root 9 Sep 20 07:11 cron.daily
cat /etc/anacrontab
# /etc/anacrontab: configuration file for anacron
# See anacron(8) and anacrontab(5) for details.
SHELL=/bin/sh
HOME=/root
LOGNAME=root
# These replace cron's entries
1 5 cron.daily run-parts --report /etc/cron.daily
7 10 cron.weekly run-parts --report /etc/cron.weekly
@monthly 15 cron.monthly run-parts --report /etc/cron.monthly
https://www.thegeekdiary.com/linux-os-service-anacron/
https://launchpad.net/~mustafakemalgilor
https://linuxconfig.org/how-to-enable-all-sysrq-functions-on-linux