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Re: The Map Is Not The Territory

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rickman wrote:
> 1 month standby???  I haven never seen a phone with 1 month standby
> time.  The real limitation is that a phone has to transmit to the cell
> tower periodically.  The receiver runs all the time.  That sets a
> baseline power consumption level which I am sure is not trivial.

GSM is time division multiplexing (TDMA+frequency hopping).  The 
receiver only has to run in the time slot you need it.  And the time is 
tested - I put an old SIM card into my LG GS100 (where nobody calls me 
on), and the battery lasts about a month.

> I don't know how they manage CPU power consumption, but who actually
> keeps a smart phone in their pocket all the time?  If you don't want
> to use the CPU during that month of standby time you are looking for,
> then why have a smart phone?

I was comparing this with a dumb phone, which can only do SMS and calls.  
There is a point to have a smartphone even when you send just short 
messages around: Doing that over Internet is several orders of magnitude 
cheaper than doing that over GSM (because the providers charge insane 
prices for an SMS).

> I can't say anything about the "GO Power Master" as I don't know what
> that is.

An Android program to check all the power management stuff.

> But I can't believe that the SDRAM refresh power is the
> limiting factor in battery life.  Using the numbers you give above for
> refresh power, I come up with nearly four weeks.

My calculation result was ~230 hours, that's not even 10 days.  The 
calculation is: 10mW at 1.35V is 7.5mA, and the PMU uses an LDO for 
this, because at 7.5mA, a switching DC-DC converter is not efficient (at 
least not cost efficient enough to add one - the DC-DC converters are 
reserved for really power hungry parts).  The battery has 1700mAh.  Ok, 
this "no DC-DC converter" is an implicit assumption that I know (because 
I worked for a company who did power management for smart phones), and 
you don't.

> You said phones have
> half a GB and the refresh power is 20 mW/GB.  So that's 10 mW refresh
> power.  Also, if the full ram is not being used at any given time,
> like in standby, they can cut the refresh to the fraction being used
> reducing the power consumption.  At least the specs I've been working
> with say this.

Well, theoretically, they could cut the refresh to the acutally filled 
memory, but in practice, they fill up all the memory (before doing 
garbage collection), and therefore, they also need to refresh 
everything.  And I think they don't want to spent that additional effort 
to refresh selectively, because it's not easy.

> The point is that you don't have to use the latest and greatest power
> hog memory for an embedded app.  There are plenty of low power memory
> devices out there, even if they aren't used in a boated "charge me
> every 8 hours" smart phone.

Of course.  The point that started this discussion was that I said: 
Memory is cheap.  But memory power consumption is not nearly as cheap as 
memory itself.  If you take your really low-power memory, it is no 
longer cheap in terms of price per MB.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/

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The Map Is Not The Territory Jason Damisch <jasondamisch@yahoo.com> - 2012-06-27 17:44 -0700
  Re: The Map Is Not The Territory dambere@web.de - 2012-06-28 02:32 -0700
    Re: The Map Is Not The Territory Mark Wills <markrobertwills@yahoo.co.uk> - 2012-06-28 02:47 -0700
      Re: The Map Is Not The Territory John Passaniti <john.passaniti@gmail.com> - 2012-06-28 13:19 -0700
        Re: The Map Is Not The Territory dambere@web.de - 2012-06-29 14:29 -0700
  Re: The Map Is Not The Territory quiet_lad <gavcomedy@gmail.com> - 2012-06-29 14:44 -0700
    Re: The Map Is Not The Territory "Elizabeth D. Rather" <erather@forth.com> - 2012-06-29 12:17 -1000
    Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-06-29 16:15 -0700
  Re: The Map Is Not The Territory quiet_lad <gavcomedy@gmail.com> - 2012-06-29 14:43 -0700
    Re: The Map Is Not The Territory Jason Damisch <jasondamisch@yahoo.com> - 2012-06-30 10:46 -0700
      Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-06-30 19:54 -0700
        Re: The Map Is Not The Territory Howerd <howerdo@yahoo.co.uk> - 2012-07-01 09:14 -0700
          Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-07-01 14:12 -0700
        Re: The Map Is Not The Territory Bernd Paysan <bernd.paysan@gmx.de> - 2012-07-01 20:40 +0200
          Re: The Map Is Not The Territory Howerd <howerdo@yahoo.co.uk> - 2012-07-01 12:15 -0700
            Re: The Map Is Not The Territory Bernd Paysan <bernd.paysan@gmx.de> - 2012-07-01 23:52 +0200
          Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-07-01 14:41 -0700
            Re: The Map Is Not The Territory Bernd Paysan <bernd.paysan@gmx.de> - 2012-07-02 00:23 +0200
              Re: The Map Is Not The Territory Paul Rubin <no.email@nospam.invalid> - 2012-07-05 00:06 -0700
                Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-07-05 10:49 -0700
              Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-07-05 10:38 -0700
                Re: The Map Is Not The Territory Bernd Paysan <bernd.paysan@gmx.de> - 2012-07-06 02:22 +0200
                Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-07-05 18:57 -0700
                Re: The Map Is Not The Territory Mark Wills <markrobertwills@yahoo.co.uk> - 2012-07-06 02:13 -0700
                Re: The Map Is Not The Territory Bernd Paysan <bernd.paysan@gmx.de> - 2012-07-07 01:11 +0200
                Re: The Map Is Not The Territory Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-07-06 10:58 +0000
                Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-07-06 06:00 -0700
                Re: The Map Is Not The Territory Paul Rubin <no.email@nospam.invalid> - 2012-07-06 20:41 -0700
                Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-07-07 06:56 -0700
                Re: The Map Is Not The Territory Paul Rubin <no.email@nospam.invalid> - 2012-07-07 21:45 -0700
                Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-07-08 15:53 -0700
                Re: The Map Is Not The Territory Paul Rubin <no.email@nospam.invalid> - 2012-07-08 21:08 -0700
                Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-07-09 16:32 -0700
              Re: The Map Is Not The Territory Brad Eckert <hwfwguy@gmail.com> - 2012-07-05 13:22 -0700
            Re: The Map Is Not The Territory Mark Wills <markrobertwills@yahoo.co.uk> - 2012-07-02 01:26 -0700
              Re: The Map Is Not The Territory stephenXXX@mpeforth.com (Stephen Pelc) - 2012-07-02 10:15 +0000
            Re: The Map Is Not The Territory "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2012-07-02 19:28 +0100
  Re: The Map Is Not The Territory Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-07-01 11:35 +0000
    Re: The Map Is Not The Territory Howerd <howerdo@yahoo.co.uk> - 2012-07-01 09:31 -0700
      Re: The Map Is Not The Territory Paul Rubin <no.email@nospam.invalid> - 2012-07-01 14:03 -0700
        Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-07-01 14:57 -0700
    Re: The Map Is Not The Territory rickman <gnuarm@gmail.com> - 2012-07-01 14:50 -0700

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