From the context of filesystems in general: If it supports directories and subdirectories, the filesystem is hierarchical. This is in contrast, to, say, the typical filesystem you found on CP/M computers in the early 80's such as a Kaypro 10, which organized files in "user" sections and had no concept of a "directory."
The term "hierarchical" in context of Linux could be a reference to how Linux, like any Unix or Unix-like system, is entirely UNIFIED in filesystems, meaning that when you stick in a thumb drive or a DVD-ROM or have another partition, they are "mounted" as opposed to the Windows method of assigning it a drive letter and treating it as a discrete filesystem with no link or relation to the other filesystems.
In Linux (And Unix(-lik)es in general.), a filesystem will be placed onto the same tree as all the others. For example, I have one filesystem for my Linux installation, and another filesystem for my data, documents, music, etc. While they are different "devices" to Linux, they are on the same tree (/ for the system partition, and my data is mounted on "/home." This method is actually superior and far more useful than the drive letter access system Windows uses. To your application software, it all looks like directories on a tree, but you can allow data to be distributed automatically between devices purely based on where the data was meant to go. Software can be installed in one partition while its configuration is on another while user data will be on yet another, yet, as long as the filesystems are mounted where intended, the application will behave as if all these things are available on the same tree.
The first file system Linux supported was the MINIX file system.
ext3 is the default file system for Red Hat Enterprise Linux.
The pros and cons of the Linux file system include the quote saying "On a UNIX system, everything is a file, if something is not a file, it is a process". You can consider this either a pro or a con.
The NTFS file system is supported in Linux by both a kernel module and several userspace programs. It is not supported as a root file system and is not recommended for permanent file storage.
The Linux VFS (Virtual File System) may be thought of as a sort of interface between the Linux kernel and the mounted file systems. There can be many different file system types mounted simultaneously and VFS allows the Linux kernel to see and address them all in a similar way. This provides Linux with a great deal of flexibility. [JMH]
The Linux ext3 file system is the default system in many linux derivatives. It allows for journalling, which the ext2 system did not. It also allows in-situ upgrades without asking for a backup first.
Traditionally in /usr/src/linux.
Super block is supposed to be the first sector of any file system that can be mounted on Linux operating system. It is supposed to contain information about the entire file system in that partition. It has magic number to specify which file system is used in that partition and other parameters to help read/write to that file system.
Depends on the file system.
A forward slash.
One.
You don't edit inodes manually. They are managed by the file system driver.