[Git][reproducible-builds/reproducible-website][master] hamburg2023: add embedded-systems notes, thanks to Hartmut

[Holger Levsen (@holger)]

Holger Levsen pushed to branch master at Reproducible Builds / reproducible-website


Commits:
7245f36c by Holger Levsen at 2023-11-13T13:33:50+01:00
hamburg2023: add embedded-systems notes, thanks to Hartmut

Signed-off-by: Holger Levsen <holger at layer-acht.org>

- - - - -


2 changed files:

- _events/hamburg2023/agenda.md
- + _events/hamburg2023/embedded-systems.md


Changes:

=====================================
_events/hamburg2023/agenda.md
=====================================
@@ -49,7 +49,7 @@ Day 2 - Wednesday, November 1st TODO
   * The day started with a summary of Day 1 outcomes and a Day 2 Agenda Overview.
 * 9.45 Collaborative Working Sessions, break-out discussions continue.
   * [Ten Commandments]({{ "/events/hamburg2023/rb-commandments/" | relative_url }})
-  * Embedded systems FIXME (no notes in the pad)
+  * [Embedded systems]({{ "/events/hamburg2023/embedded-systems//" | relative_url }})
   * [Guix To-do's]({{ "/events/hamburg2023/guix-todo/" | relative_url }})
   * [Signature storage and sharing]({{ "/events/hamburg2023/signature-storage/" | relative_url }})
   * [Public verification service]({{ "/events/hamburg2023/verification1/" | relative_url }})


=====================================
_events/hamburg2023/embedded-systems.md
=====================================
@@ -0,0 +1,63 @@
+---
+layout: event_detail
+title: Collaborative Working Sessions - Embedded systems
+event: hamburg2023
+order: 202
+permalink: /events/hamburg2023/embedded-systems/
+---
+
+# What are embedded systems:
+
+* All systems which is not a PC, Software in a device.
+* Industrial control (PLC = programmable logic control)
+* Software in a toaster or dishwasher
+* Small and powerful systems given:
+* Small: TMS430 Series, 32 kByte ROM, 512 Byte RAM,
+* Powerful: Raspi as controller
+* => Focus to small systems, because powerful have often a Linux Kernel,
+* Using a specific Real time operation system or not, no difference
+* (If RTOS is used, it should be also reproducible)
+
+# Challenges
+
+* Different Target systems, different compilers from diff. vendors, more         variablility.
+* comprehensibility process how the binary is built
+* traceability of build process.
+* Reprod. Build should be a part of the approval procedure for a device.
+
+# Solutions:
+
+* All solutions known for gcc should be also applied to all known compiler,
+* Is it done or in focus? Responsibility from the compiler vendors for this topic
+
+# Notes during session
+
+* Reproducible required: Gambling industry requires it. restrict regulation.
+* look for gcc link time optimization.
+
+## Look for:
+
+* Debugging information in the object:
+* 1) with the same path, different machines.
+* 2) diff. path on diff machines
+* If the path is a symbolic link (or Junction in Windows), the Compiler should not resolve the symbolic linked path, then the path is able to make unique.
+* Use Option remove debug symbols.
+* Always use the same compiler version.
+
+
+* Build info file is not very well standardized? Look for https://wiki.debian.org/ReproducibleBuilds/BuildinfoFiles
+* Have a script for all stuff of build inputs
+* Language for sorting its a topic to the build system. (for linker), use always US-ASCII-sorting
+* Optimizations should not randomized or have start seed. SDE Source date epoch as seed.
+* Parallel compilation makes problems? Order of files.
+
+gcc is reproducible by default. with the same source path. Or have not debug symbols.
+build-id.
+
+## Changing and testing: Test effort. 
+
+What about changing sources in a small way, reprod. build gives only small changes, test only the differences:
+
+* Have to be more as one binary for the solutions. using dll libs ?
+* Use static link, compare object files. Look from where comes the difference
+



View it on GitLab: https://salsa.debian.org/reproducible-builds/reproducible-website/-/commit/7245f36c4d100ad7fbdc0553a2eae12999f14730

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