Hi!

I have an old Intel-i5 Fujitsu Laptop which has Windows in its internal hard disk and a Linux multiboot on an external SSD.

Installing on the external disk has been the subject of some rather confusing (my own fault) threads since about 2 years ago:

4- How-i-was-finally-able-to-boot-from-a-stubborn-external-usb-hard-disk-4175710196/

3- Exect-format-error-upon-booting-from-full-install-on-external-multiboot-bios-uefi-hd-4175699692/

2- Exec-format-error-upon-boot-on-fresh-install-on-usb-stick-4175689683/.

1- Exec-format-error-upon-boot-on-fresh-install-4175689612/

This morning I tried to start Slackware to use as a support computer while updating Slackware on my multiboot desktop and got a message that the partition could not be mounted on /mnt and that a /sbin/init was missing, and that I could try to solve it in a shell provided below the message.

I then used the for me magical incantation that had worked before: and "voila'!" the partition was mounted and when I entered it proceeded to boot Slackware and then I was soon on my desktop.

When I first got the error I immediately rebooted (I am still a newbie) and from another distro checked the fstab, opened the partition and ran fsck on the partition, with no errors found.

This partition runs on generic-5.15.63, with a tailormade initrd as related in How-i-was-finally-able-to-boot-from-a-stubborn-external-usb-hard-disk-4175710196/and has always been stable.

So now I am posting from Slackware and it seems pretty normal.
But I am disturbed by not understanding what is going on.

I had finally believed that the problems I experienced in booting from the external disk were related to some module(s) missing in the initrd, which I tried to solve with a more inclusive initrd.

But now I am at a loss again, and I am an older man who grew up under the ideal of understanding things, which I think was what made me so found of Slackware. It is all about learning isn't?

That is why I am still posting. I would like to hear a conceivable reason for a missing "/sbinit/init" and why the mentioned command worked and could it be any relationship between this 2 aspects?

I understand this interest may sound excessive, but I have succeeded in getting great instruction before from the Slackware community!

Season Greetings to all!

If you boot from an external SSD it is probably through USB connection. In such a case, the kernel may require some time to initialize the USB subsystem and make your device node such as /dev/sdb available. If that is the case, your use of "nosuid" does not matter, because the thing that did matter was time passing.
You could test this idea bu adding a wait of, say, 10 seconds to the boot process.
Slackware's mkinitrd has a parameter for this:

Thanks Windu, for a quick answer.

The w option was pointed to me in those early threads.

I found out what was the problem immediately upon posting, when I closed my browser and looked at the desktop: there were no icons for my partititions, only icons for "/proc" and similar. Then I tried to sudo/su and got messages that I could not and one of those mentioned it might have to do with "nosuid" mounting, so I rebooted (had to logout and in as root) and when I looked at the Slackware stanza under GRUB it had root=/dev/sdc10.
As there are only 2 block devices I wondered and then remembered paying attention to a list of sdb1.......sdb16 in the booting output, and remembered clearly that I had written "/dev/sdb10" in the command that finally booted Slackware.

So I edited the grub stanza and booted swiftly.

And I then first thought that I had updated grub (running under Artix) last night (i.e. 5:00 this morning).

I don't know how that stanza turned out wrong, I can understandthough that these things happen not so seldom, so my need for comprehension is satisfied now: there was nothing magical about the command. It was the right device identification that fixed it. No magic !

This is solved !