Flash and SSD storage devices are faster than spinning disks because they have no moving parts. They can be even faster. They are still accessed using SCSI protocol that sends one command at a time. With NVMe (Non-Volatile Memory Express), a protocol that will be used to access SSDs via PCIe interface.
This is an excellent introduction to NVMe: NVMe for Absolute Beginners.
I took the Linux Kernel fundamentals course on Linkedin Learning during the Week of Learning. I went through the first three lessons. The last two deals with compiling the kernel. I skipped them as I had done some kernel compiling years ago and I won’t be doing them anytime soon.
These are my notes from the lessons:
I have always thought Virtual Filesystems like /proc and /sys are stored in memory, they are not. They are generated when asked for it. Each file and directory has associated function in the kernel that generates the content when you ask.