Re: Most energy efficient (home) setup

[Steven Bellovin <smb () cs columbia edu>]

On Apr 18, 2012, at 5:55 32PM, Douglas Otis wrote:

> On 4/18/12 12:35 PM, Jeroen van Aart wrote:
> > Laurent GUERBY wrote:
> > > Do you have reference to recent papers with experimental data about
> > > non ECC memory errors? It should be fairly easy to do
> > Maybe this provides some information:
> >
> > http://en.wikipedia.org/wiki/ECC_memory#Problem_background
> >
> > "Work published between 2007 and 2009 showed widely varying error
> > rates with over 7 orders of magnitude difference, ranging from
> > 10−10−10−17 error/bit·h, roughly one bit error, per hour, per
> > gigabyte of memory to one bit error, per century, per gigabyte of
> > memory.[2][4][5] A very large-scale study based on Google's very
> > large number of servers was presented at the
> > SIGMETRICS/Performance’09 conference.[4] The actual error rate found
> > was several orders of magnitude higher than previous small-scale or
> > laboratory studies, with 25,000 to 70,000 errors per billion device
> > hours per megabit (about 3–10×10−9 error/bit·h), and more than 8% of
> > DIMM memory modules affected by errors per year."
> Dear Jeroen,
>
> In the work that led up to RFC3309, many of the errors found on the Internet pertained to single interface bits, and 
> not single data bits.  Working at a large chip manufacturer that removed internal memory error detection to foolishly 
> save space, cost them dearly in then needing to do far more exhaustive four corner testing.  Checksums used by TCP 
> and UDP are able to detect single bit data errors, but may miss as much as 2% of single interface bit errors.  It 
> would be surprising to find memory designs lacking internal error detection logic.


mallet:~ smb$ head -14 doc/ietf/rfc/rfc3309.txt | sed 1,7d | sed 2,5d; date
Request for Comments: 3309                                      Stanford
                                                          September 2002

Wed Apr 18 23:07:53 EDT 2012


We are not in a static field...  (3309 is one of my favorite RFCs -- but
the specific findings (errors happen more often than you think), as
opposed the general lesson (understand your threat model) may be OBE.


                --Steve Bellovin, https://www.cs.columbia.edu/~smb