Re: Forcasts, why won't anyone believe them?

[abender () taqua com]

From: Sean Donelan <sean () donelan com>
> They may hate to give out this information, but any piece of 
> equipment with a NEBS level 3 rating already has this information.  
> I'm not asking for vendors to do the full, burn the box, NEBS 
> testing.  But having the power drain data sheet would be very useful.
>
> This is really a customer demand issue.  If customers started 
> demanding vendors supply a full NEBS-like space and power planning 
> data sheet, we would get the information.  But customers don't, so 
> we don't.

I suspect the availability of data is not the only/key issue here. If
pressed (asked correctly, etc.), most vendors can provide some
approximation of worst case system or per-subsystem current
requirements, whether they have done/can spell NEBS or not. Even though
it is non-trivial to measure instantaneous peak drain empirically, there
are other ways to get reasonable bounds on it, and doing so is a routine
practice of hardware engineers.  

A reason that the most careful power capacity forecasts (in particular)
may *seem* to be perpetually optimistic, might be the needlessly high
peak to average drain ratio of (most?) equipment. 

If customers can convince vendors that they have more concern about the
ancillary costs of operating equipment, vendors might be induced (pun!)
to make some nominal sacrifices in cost and MTBF to include features
like inrush current limiting, and sequencing. Get your RFPs ready.

Regards,
Andrew Bender
taqua.com