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

On 5/20/2025 7:29 PM, Lawrence D'Oliveiro wrote:

On Tue, 20 May 2025 10:49:54 -0400, Stefan Monnier wrote:
 

Indeed, AFAIK, what we call "HDD cache" is actually just the RAM used by
the embedded CPU inside the drive for its operation.

 If it were just I/O buffers for operations in progress, that would be
fine. The problem is when it keeps data around instead of immediately
writing it out, and what’s worse, lies about it, so it tells the OS that
the write has completed when it hasn’t.

Note that (with SATA and similar) the OS can request that the drive flush its caches, and (in theory) drive should not respond to more requests until everything has been fully written back to disk.
Though, admittedly, I don't have much first-hand experience with interfacing directly with SATA drives.