Some Other Scheduling Issues
Learn where disk scheduling occurs in modern systems, how both the OS and disk controllers coordinate to optimize I/O requests, and the role of techniques like I/O merging and anticipatory scheduling. Understand how non-work-conserving approaches can improve disk efficiency by waiting for better requests before issuing I/O operations.
We'll cover the following...
Where is the disk scheduling performed?
There are many other issues we do not discuss in the brief description of basic disk operation, scheduling, and related topics presented in the previous lesson. One such issue is this: where is disk scheduling performed on modern systems? In older systems, the operating system did all the scheduling; after looking through the set of pending requests, the OS would pick the best one, and issue it to the disk. When that request is completed, the next one would be chosen, and so forth. Disks were simpler then, and so was ...