Lecture 11 assignment
In preparation for the lecture about I/O, please answer the
- What cache replacement policy does bio.c (sheet 45-53) implement?
Can a buffer both be on a block device list
bdevsw[dev.d_major].d_tab) and the free list
bfreelist)? When a block is released, is it removed
bdevsw[dev.d_major].d_tab? When a block is
released, where is it inserted in
bfreelist? Chapter 17
and the beginning of chapter 15 (15-1) may be good reading.
- The RK device (the disk) operates in parallel with the processor,
yet they share a number of registers (rkds, rker, rkcs, rkwc, rkba,
rkda). Can it happen that the processor and the RK device ever write
both to the same register at the same time? Explain why it cannot
happen, or give an example of a register that could be written by both
at potentially the same time? Chapter 16 might be helpful.