Re: safe file systems

Rob Hagopian (
Thu, 25 Sep 1997 16:19:20 -0400 (EDT)

Actually, Apple got bitten by this one a little while ago... Because they
actually turn off the whole system on a shutdown command, the
internal hard drive loses power too. Some Quantum drives they shipped had
write caching turned on, and the power would cut out before the cache was
flushed on the drive!
-Rob H.

On Wed, 24 Sep 1997, David S. Miller wrote:

> From: (Larry McVoy)
> Date: Wed, 24 Sep 1997 12:22:23 -0700
> The default on every SCSI & FC disk I've ever seen (and I've seen a
> fair number including drives from HP, Seagate, Quantum, IBM,
> Maxstor, and probably others I'm forgetting) is to /not/ do write
> caching. If the drive says the write is done, it is done.
> Sort of. I know there are drives which write cache, but only do so
> such that the energy from the spindown from a power failure is 2 or 3
> times more than would be needed to do the last minute flush of any
> cached writes.
> Later,
> David "Sparc" Miller