On Mon, 27 Jul 2020, Warner Losh wrote:

> I've done some research for a friend about when the reboot() system call 
> was added, and how it related to the sync, sync, sync dance. 
> https://bsdimp.blogspot.com/2020/07/when-unix-learned-to-reboot2.html
> 
> may be of interest. Please do let me know if I've gotten 
> something wrong...

Seems OK to me; I was taught never to use "sync; sync; sync" for precisely 
those reasons (the buffers may not have time to flush etc, as "sync" 
merely schedules the I/O, not cause it.

-- Dave