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Groups > comp.arch.embedded > #24842

Re: What is your strategy to save non volatile data?

From Les Cargill <lcargill99@comcast.com>
Newsgroups comp.arch.embedded
Subject Re: What is your strategy to save non volatile data?
Date 2016-08-12 12:15 -0500
Organization A noiseless patient Spider
Message-ID <nokvsh$b28$1@dont-email.me> (permalink)
References <nohs7p$ff3$1@dont-email.me>

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pozz wrote:
> Many times I work on embedded projects where it is required to save some
> data in a non volatile way.  Usualy I use external (to the main
> microcontroller) serial/parallel EEPROM or internal Flash memory (with a
> software layer for EEPROM emulation).
>
> However my goal isn't to discuss the hw alternatives, but the data
> format and strategy.
>
> I know there are many serialization data format (XML, JSON, Protocol
> Buffer, SQLite), but I don't think they are valid solutions for
> medium/low end microcontrollers.  They are complex to implement and they
> aren't really necessary.


They call these "serialization formats".

The simplest XML solution I've found is ezXML. It's sort of fiddly.
JSON is another choice. IMO, JSON is a little easier to look at.

This being said, just dotted names in a text file is equivalent to
each of these. Line of Class.instance.42.attribute.thing="86.42"\n works 
just as well.

> Data are written and read from the same platform, so the endianess and
> byte order are not a problem.
>

Text formats make this problem go away.

> IMHO directly saving a C structure to the non-volatile memory is the
> best method.

Unless the shape of the struct changes. Having to maintain and feed a 
version ID to cover all possible struct shapes is a pain.

> When you will load bytes from the non volatile memory, you
> will have magically your C structure in RAM filled with the saved values.
>
> Is it the same strategy that you use?

I have, but there's some advantage to mapping the struct to a text file 
of attribute-value pairs through a table of names. How much trouble
this is depends on how many attribute value pairs you're storing.

-- 
Les Cargill

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Thread

What is your strategy to save non volatile data? pozz <pozzugno@gmail.com> - 2016-08-11 14:48 +0200
  Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-11 06:27 -0700
  Re: What is your strategy to save non volatile data? David Brown <david.brown@hesbynett.no> - 2016-08-11 16:12 +0200
    Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-11 07:53 -0700
      Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-11 08:27 -0700
        Re: What is your strategy to save non volatile data? bitrex <bitrex@de.lete.earthlink.net> - 2016-08-11 12:11 -0400
          Re: What is your strategy to save non volatile data? bitrex <bitrex@de.lete.earthlink.net> - 2016-08-11 12:12 -0400
            Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-11 11:35 -0700
              Re: What is your strategy to save non volatile data? bitrex <bitrex@de.lete.earthlink.net> - 2016-08-11 20:59 -0400
          Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-11 11:33 -0700
        Re: What is your strategy to save non volatile data? pozz <pozzugno@gmail.com> - 2016-08-12 00:21 +0200
          Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-11 15:40 -0700
      Re: What is your strategy to save non volatile data? David Brown <david.brown@hesbynett.no> - 2016-08-11 23:07 +0200
        Re: What is your strategy to save non volatile data? pozz <pozzugno@gmail.com> - 2016-08-12 00:17 +0200
          Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-11 15:30 -0700
            Re: What is your strategy to save non volatile data? pozz <pozzugno@gmail.com> - 2016-08-12 09:02 +0200
              Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-12 09:29 -0700
            Re: What is your strategy to save non volatile data? David Brown <david.brown@hesbynett.no> - 2016-08-12 11:54 +0200
              Re: What is your strategy to save non volatile data? John Devereux <john@devereux.me.uk> - 2016-08-12 13:14 +0100
                Re: What is your strategy to save non volatile data? David Brown <david.brown@hesbynett.no> - 2016-08-12 15:22 +0200
              Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-12 09:40 -0700
                Re: What is your strategy to save non volatile data? David Brown <david.brown@hesbynett.no> - 2016-08-12 22:40 +0200
                Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-13 09:44 -0700
                Re: What is your strategy to save non volatile data? David Brown <david.brown@hesbynett.no> - 2016-08-14 23:01 +0200
          Re: What is your strategy to save non volatile data? David Brown <david.brown@hesbynett.no> - 2016-08-12 09:52 +0200
            Re: What is your strategy to save non volatile data? pozz <pozzugno@gmail.com> - 2016-08-12 16:30 +0200
              Re: What is your strategy to save non volatile data? David Brown <david.brown@hesbynett.no> - 2016-08-12 17:09 +0200
        Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-11 15:36 -0700
        Re: What is your strategy to save non volatile data? Paul <paul@pcserviceselectronics.co.uk> - 2016-08-12 03:21 +0100
    Re: What is your strategy to save non volatile data? bitrex <bitrex@de.lete.earthlink.net> - 2016-08-11 12:19 -0400
      Re: What is your strategy to save non volatile data? pozz <pozzugno@gmail.com> - 2016-08-11 23:49 +0200
        Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-11 15:37 -0700
    Re: What is your strategy to save non volatile data? John Devereux <john@devereux.me.uk> - 2016-08-11 20:50 +0100
    Re: What is your strategy to save non volatile data? pozz <pozzugno@gmail.com> - 2016-08-12 00:16 +0200
      Re: What is your strategy to save non volatile data? Paul <paul@pcserviceselectronics.co.uk> - 2016-08-12 03:34 +0100
      Re: What is your strategy to save non volatile data? David Brown <david.brown@hesbynett.no> - 2016-08-12 11:59 +0200
  Re: What is your strategy to save non volatile data? Paul Rubin <no.email@nospam.invalid> - 2016-08-11 11:29 -0700
  Re: What is your strategy to save non volatile data? Les Cargill <lcargill99@comcast.com> - 2016-08-12 12:15 -0500
  Re: What is your strategy to save non volatile data? Joe Chisolm <jchisolm6@earthlink.net> - 2016-08-12 12:10 -0500
    Re: What is your strategy to save non volatile data? Paul <paul@pcserviceselectronics.co.uk> - 2016-08-12 22:00 +0100
  Re: What is your strategy to save non volatile data? Tim Wescott <tim@seemywebsite.com> - 2016-08-13 12:06 -0500
    Re: What is your strategy to save non volatile data? pozz <pozzugno@gmail.com> - 2016-08-13 23:42 +0200
      Re: What is your strategy to save non volatile data? Don Y <blockedofcourse@foo.invalid> - 2016-08-13 15:55 -0700
      Re: What is your strategy to save non volatile data? Paul <paul@pcserviceselectronics.co.uk> - 2016-08-14 00:08 +0100
      Re: What is your strategy to save non volatile data? Tim Wescott <tim@seemywebsite.com> - 2016-08-13 19:06 -0500
        Re: What is your strategy to save non volatile data? pozz <pozzugno@gmail.com> - 2016-08-22 09:46 +0200

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