[Nut-upsdev] Asking hard questions about the NUT architecture

[Carlos Rodrigues]

On 5/30/07, Eric S. Raymond <esr at thyrsus.com> wrote:
> Yes, the systems I administer have been behaving that way since the
> mid-1980s (except that it never worked on the ISA boxes).  It's a
> *really* short time, like on the order of 250ms, but enough for buffer
> flushes.  If that weren't so, ext3-like file systems couldn't achieve
> their main purpose.  Heck, if that weren't so disk drives wouldn't
> be able to autopark their heads.

Errr, drives autopark their heads with a simple spring mechanism.
Remove power, and the heads are pulled back by Isaac Newton's ghost.

And ext3 achieves its main purpose because the hardware guarantees
that an acknowledged write request for a single 512 byte block is
commited to disk even if the drive loses power. That's *512* bytes!

-- 
Carlos Rodrigues