Drives 1 and 2 are bootable (not live) 64GB USB flash drives on which I have installed Ubuntu 22.04.1 LTS. I boot the computer using Drive 1, to study the health of Drive 2 (/dev/sdb).
Drive 2 is divided into 2 MiB unallocated, followed by /dev/sdb2 (477 MiB FAT32) and /dev/sdb3 (59 GiB ext4). Both partitions are at least half-empty.
When I ran sudo fsck /dev/sdb I got "Bad magic number in super-block" results similar to those in another thread. The advice in that thread was, in effect, to run sudo fsck -f /dev/sdb3. For me, that command went through passes 1 through 5 with no reported errors. A check of sdb3 in GParted likewise reported no errors.
Those fsck results seemed inconsistent. I thought the explanation might be that the "bad magic number" message was referring to the FAT32 partition. But that wouldn't make sense: the message acknowledged that partition: "Found a dos partition in /dev/sdb." Surely the message was not telling me that a DOS partition would not function as a proper Linux partition. The message seemed rather to be highlighting a problem with sdb3.
The "bad magic number" message itself seemed to recommend running sudo e2fsck -b 8193 or 32768 (the two superblock numbers it suggested). With 32768, the command seemed to work, but it did not seem to have any effect: it purported to "fix" many problems that, on re-run, were still there.
A participant in a different discussion, responding to the same "bad magic number" message, suggested both mke2fs -n /dev/sdb3 and fdisk /dev/sdb. Not sure what these might add, or why they would be on target.
I seem to be flailing around without a clear understanding of the problem and its solution, or even whether there is a problem.
