# Reconciling program & data size numbers

**URL:** <https://community.keyboard.io/t/reconciling-program-data-size-numbers/2891>\
**Category:** Programming\
**Tags:** question\
**Created:** [May 24, 2019, 3:40am UTC](https://community.keyboard.io/t/reconciling-program-data-size-numbers/2891 "2019-05-24T03:40:08Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![merlin](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.keyboard.io/merlin/32/3416_2.png) [@merlin](https://community.keyboard.io/u/merlin)\
**Post date:** [May 24, 2019, 3:40am UTC](https://community.keyboard.io/t/reconciling-program-data-size-numbers/2891/1 "2019-05-24T03:40:08Z")

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I spent a few hours today trying to figure out how to account for everything that gets stored in RAM for a given firmware sketch, but I have been unsuccessful getting any of the numbers reported by different tools to agree.

I’ve compared the number reported as “Data” when building the sketch to the numbers I get from `make size-map`, and also @noseglasses’ `elf_diff` program, but I no matter how I sum the different amounts, I can’t get any two of those tools to give me the same results.

I feel like the size map output (from `avr-nm`) ought to be giving me the information I need to identify the source of each byte of RAM used, but I’m unable to make sense of it, and find myself doubting all these numbers because I can’t reconcile them with each other.

I’ve searched for a resource to help understand the output of these kinds of tools better, but I haven’t found anything helpful yet. Can anyone here point me at an introductory tutorial on this topic?