Linux Disk I/O subsystem diagram This diagram represents Linux disk I/O subsystem components and the corresponding commands on each layer.   Linux disk I/O diagram consists from the: Application layer VFS (Virtual Filesystem): Direct I/O or Buffer+Page Cache  Filesystem Layer Optional block layer Generic block layer Disk scheduler layer: BLK-Mq or Clasic I/O scheduler (noop, anticipatory, deadline, cfq, ...) Block device driver layer Device driver Hardware: RAID controller or Disk controller Hard disk drives (HDD, SSD, NVMe, ...).   This diagram is integral part of the book: Operativni sustavi i računalne mreže - Linux u primjeni https://doi.org/10.5281/zenodo.8119310