Subject: [OPSAWG] Power states

From: Bruce Nordman <[email-masked]>
Date: Fri, 23 Apr 2010 09:59:21 -0700

On the topic of how many and what names for power states,
I confess I have not fully read the drafts yet but wanted to
offer my thoughts now to be timely.

Terminology around "standby" is really more oriented to
a functional state than a power state, and in my last 15 years
of dealing with this topic, I have found 'standby' unsuitable
for names of power states (I use 'state' and 'mode' interchangeably).
It is inherently ambiguous as to whether it is on, off, sleep, or some
combination. 

Many standards have settled on the On/Sleep/Off terms as three
standard "buckets" of modes.  These are clearly distinct from each
other, and no question about their ordering.  The boundaries between
them are not rigidly defined across all products, but for particular
products, the meaning is usually quite clear (hibernate being the only
substantial area where there are multiple reasonable rationales for
how to treat it).

The sleep metaphor is used by many technology standards, from
physical layers (e.g. Ethernet) up through the user interface (IEEE
1621), and by many operating systems, including Windows and
MacOS. 

My recommendation would be to have the MIB include two
levels to the state - one of on/sleep/off that applies consistently
across all products, and then optional substates within that would
be product-specific.  I think this maximizes the amount of order
that can be reasonably applied, while also provides flexibility for
finer-grained exposing of the state.  I can't offer an opinion today
on how specifically this should be implemented the RFC.

The above applies to electronic devices; for non-electronic ones
(e.g. appliances), it may make sense to add a "ready" mode.

It would be helpful to document somewhere common substates
within the three major "buckets" - these will in some cases be
product-specific (particularly for transitional modes) but some
overall useful patterns may emerge.

Cheers,

--Bruce

-- 
Bruce Nordman
Lawrence Berkeley National Laboratory
[email-masked] -- 510-486-7089
eetd.lbl.gov/ea/nordman/