When is data within a file written to disk from the buffer cache?   A. Whenever a file is modified by a process, if the O_SYNC flag is set for that open file.   B. Periodically, usually dependent on a system daemon (if the block in the buffer cache is different from the disk image of the block).   C. Whenever a user process issues the 'sync()' system call (if the block in the buffer cache is different from the disk image of the block).   D. All of the above.

Operating systems make an effort to save individual pieces of a file in a sequential fashion on disk. So what if we use magnetic disks for it?SSDs: necessary even if you don't use them? Is this anything that we can figure out?

What is the optimum file access pattern for a chained disk allocation of files??

195. In case the buffer manager do not write the blocks properly then the buffer manager uses a. Replacement strategy b. Forced strategy c. Crash recovery system d. Both Replacement and Forced strategy