Slideshow:

Location - store all sectors of a block under each other

Disadvantage: need to use large capacity disks

Striping: split file over multiple (smaller) disks

Advantage = multiple disk head can seek and transfer data in parallel

Scheduling: First Come First Serve ?

FIFC: requests are served in the order received

Advantage/Disadvantage of FCFS

Scheduling: Elevator Algorithm

Elevator Algorithm:

Disk head sweeps in and out
Service a request when the block is located in the cylinder

Example of the "Elevator Algorithm"

Advantages/Disadvantages of the "Elevator Algorithm"

Comment: the Elevator Algorithm is used in all disks today

Pre-fetching: set up

Set up: reserve multiple buffers

Pre-fetching: initial read

Initialization: read data into a buffers

Pre-fetching stead state: read and process simultaneously

Steady state: read data into buffer 1 while process data in buffer 2