There are no letters at disks, like in DOS/Windows -> Everything is under /
It mounts (connects) the external storages
Nowadays Windows is also capable of it
The /etc/fstab file contains the automatical mount point of partitions and settings associated with them.
fdisk or fdisk -l commands, latter one lists the partitions.
Under /mnt we can find the mounted mediums (but that's not true mostly because in modern partitions the automatically mounted mediums like flash drives usually get mounted to /media, but that's true that /mnt is created to mount partitions there)
EXT structure
FAT-table contains entries for every cluster on a continuous area of the medium. Every entry contains the next cluster's number in a file or the EOF (end of file), unused disk space and the specially reserved space of the disk. It only can do soft-link.
EXT filesystem: It uses inode(Index node) table. In inode there are the files' description and the place of the data blocks, without filename. There is only one inode for each file. Files with bigger size may contain multiple catalog-entries, which contains the filename. Inode contains the name, description, creation date, permissions, owner(UID), group(GID), and how many links are attached to it. (so it can do much more than FAT) It can do soft-link and hard-link, which is one of the biggest advantage of EXT file system to FAT.
Soft-link: shortcut, if the original gets deleted, then it deletes itself, or it says error that it doesn't find the executable.
Hard-link: A copy of the file, but if we change the original one, then the content of the copy changes, but the file will only disappear eventually, if all the copies are deleted.
Tasks of it: handling peripherals, handling filesystem, implementing directory structure, taking control of processor
Types of kernels:
Monolithic: The kernel consists of one unbreakable unit module. It's common for older Linuxes (older than 2.0) and UNIX systems.
Hybrid: like Windows – permissions can be set. Hybrid kernels are basically microkernels in which some "not important" code parts have been moved from user level (userspace) to kernel level (kernelspace) using fewer abstractions to run faster.
Microkernel: Kernel is in multiple small programs, not in one big module.
Modular: The modular kernel tries to fix the monolithic kernel's problems. Parts of the kernel - physical and logical - and modules created by this, which are mostly drivers can be loaded into memory. It saves the size of the kernel, but both together becomes bigger and bigger (its size is relative though, it depends how many drivers do you want to add, complete kernels are mostly around 100 MB or above, but if you are minimalist, it can be under 10 MB). We put modern Linux systems under the modular term (to be punctual, Linux kernel is monolithic modular). The kernel modules can be found in /lib/modules/kernel-version folder.
Place of kernel: It's in the /boot folder, and there are soft-links to vmlinuz and initrd in the root.
The first user has also root permissions (which you set in the installation) - but this depends on distribution, e.g. Debian users have no root permission by default, and there is no sudo.
