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Date: Wed, 02 Aug 2006 19:12:23 +0100
From: Ian Stirling <ian.stirling@mauve.plus.com>
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To: Krzysztof Halasa <khc@pm.waw.pl>
CC: Kyle Moffett <mrmacman_g4@mac.com>, David Masover <ninja@slaphack.com>,
       David Lang <dlang@digitalinsight.com>,
       Nate Diller <nate.diller@gmail.com>,
       Adrian Ulrich <reiser4@blinkenlights.ch>,
       "Horst H. von Brand" <vonbrand@inf.utfsm.cl>, ipso@snappymail.ca,
       lkml@lpbproductions.com, Jeff Garzik <jeff@garzik.org>,
       "Theodore Ts'o" <tytso@mit.edu>,
       LKML Kernel <linux-kernel@vger.kernel.org>, reiserfs-list@namesys.com
Subject: Re: Solaris ZFS on Linux
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Krzysztof Halasa wrote:
> Kyle Moffett <mrmacman_g4@mac.com> writes:
> 
> 
>>IMHO the best alternative for a situation like that is a storage
>>controller with a battery-backed cache and a hunk of flash NVRAM for
>>when the power shuts off (just in case you run out of battery), as
>>well as a separate 1GB battery-backed PCI ramdisk for an external
>>journal device (likewise equipped with flash NVRAM).  It doesn't take


> Not sure - reading flash is fast, but writing is quite slow.
> A digital camera can consume a set of 2 or 4 2500 mAh AA cells
> for a fraction of 1 GB (of course, only a part of power goes
> to flash).

Yeah - that's why I said in the original message that it's not
especially lower in energy - the energy is used at a lower rate,
so is much cheaper to supply.
http://www.samsung.com/products/semiconductor/NORFlash/256Mbit/K8A5615EBA/K8A5615EBA.htm 
's datasheet says to program the 32Mbyte chip takes about 30mw*120s, or 
3.5J or so.
For a gigabyte, that's 100J - a fairly substantial amount of energy.
However - it's at a low rate, so it's not _too_ expensive to supply.