The "device" man mount speaks of is a logical block device with a filesystem on it.
A "device" can also mean a product (SSD is a drive, HDD is disk drive, DVD is disk, ODD is disk drive.
Often it does not matter which exactly. But when it comes to mounting (or formatting, or partitioning), it does matter, because it matters logically.
As you can see, sda is right beside sda1, 2, 3 ...And also sdb, sdc, each with their partitions. So you can go wrong both ways.
mount /dev/sdb1 /media/disk/, you are choosing partition 1 from sata disk "b". If that sdb1 is a USB pen partition, then your mountpoint's name is not very speaking.
You can even mount a piece of RAM to make a ramdisk, or a file ("loop device"). Or a all-virtual "device" like sysfs, which populates /sys directory (mountpoint).
The idea of mounting, and thus the command mount, rely on a concept (VFS etc.) with three main elements:
- Partition/block device: compare
cat /proc/partitions. It is tricky, but 80% is just different points of view.
- File System: Formatting turns a 20GB partition into a empty directory with 18GB free space to fill with files. See
man mkfs and
man mkfs.ext2 (mkfs.FSTYPE).
- Mountpoint: This is just a "hook", a (empty) directory to which the new branch is attached to top directory "/". By binding and overlaying you can create complicated FS trees. But any ad hoc
mkdir xyz is fine, technically.
All this mounting was once configured by the sysadmin in /etc/fstab, centrally. With today's hot-plugging of mass storage, things get a bit complicated.
In the case of a USB pen it is a kernel module that pops up /dev/sdb and its partitions in a split second.
All further automation in hot-plugging, simple as it is, has to be coordinated by udev, and sometimes perfected by additional tools. Udev can handle ALL devices, not just storage.
We are caught between the comfort of having a new icon (or even just a "device" with a decent name) pop up automatically, and the way the kernel with the (virtual) file system systematically has to prepare the parts. But with RAID and encryption and all the different storage "devices" Linux has to add some layers.
In the end, you want that contents at your fingertips.
Normally, you only have to identify the correct...DEVICE ;). You can
ls /dev/sd* to see what is there: which letters, which numbers, identify your DEVICE...
And then type
mount /dev/DEVICE mydev
(You can leave out the
-t type part)