Re: Is Parallel Programming Hard, And, If So, What Can You Do About It?

On Mon, 12 May 2025 08:05:56 +0200, Terje Mathisen wrote:

Lawrence D'Oliveiro wrote:

>
One of my pet peeves is disk drives with memory caches in them. Why?
 

For reads it allows the disk to always read full sets of sectors, the
following blocks are likely to be needed soon anyway.

Leave that up to the OS I/O optimization algorithms. Because they know
things about the data that the drive doesn’t.

For writes, as long as the drive has enough energy (maybe in the form of
spinning inertia, or a hefty cap?) the always be able to save the buffer
cache to spinning rust, it can allow operations to complete immediately,
or as soon as the data has been transferred into the disk cache.

In other words, telling lies to the OS that the write has completed when
it hasn’t. This kind of thing can really stuff up filesystem integrity
guarantees.