Re: automatic sleep on external USB disks?

[Giles Lean <giles.lean%pobox.com@localhost>]

Michael van Elst <mlelstv%serpens.de@localhost> wrote:

> Unlikely, I haven't seen any USB to ATA converters that allow you
> to pass through ATA sleep commands.

Some do, however, put disks to sleep after a period of inactivity.  It
seems like the luck of the draw when you buy one though whether the
enclosure will or not, and you'll probably get one that leaves the disk
spun up for life, as that's the "typical" behaviour.

The only thing that makes me wonder if there isn't more that can be done
in software is that in my experience external USB disks connected to OS
X tend to do a better (i.e. they usually spin down when inactive) than
when they're connected to NetBSD.  But perhaps I've just been lucky with
the enclosures I've used with OS X and unlucky (or less lucky) with the
enclosures and disks I've used with NetBSD.

Unfortunately, it would likely take someone with several spare external
disks and enclosures, a lot of patience, a USB analyzer, and both OS X
and NetBSD systems to demonstrate if there's anything different in the
behaviour at all. As I'm missing serveral of those items (USB analyzer,
spare disks, time) I'm afraid I'll have to pass. :-(

I keep hoping that eSATA will get some momentum: with USB3 on the
horizon I suspect my hopes will be dashed again, and for the next
few years we'll continue to see dodgy external USB disk enclosures
as the "cost effective" consumer solution.

The only good thing is that disk prices have come down, so having one
die a premature heat death isn't as terrible as it once was.

Giles