Executive Summary General Protection Faults (GPFs) in ZeroMQ-powered applications can bring production systems to a halt due to unsafe memory access. These faults are especially common in multi-threaded Python environments where improper socket sharing and context management occur. This article walks through a real-world scenario from a distributed camera processing system, showcasing how adopting thread-safe ZeroMQ practices completely resolved repeated crashes. The Problem: Understanding General Protection Faults What Is a General Protection Fault? A GPF is a critical error that occurs when a program accesses protected or invalid areas of memory. In the context of ZeroMQ: python3 general protection fault ip:7847bbbf4660 sp:7847fbffc830 error:0 in libzmq-56587b1b.so This log indicates: Process: Python3 Cause: Illegal memory access inside the libzmq shared library Result: Hard crash — the Python process is forcefully terminated Why

BackgroundPreviously, we successfully deployed our React application on a Raspberry Pi 4 using NGINX. However, after migrating to a Raspberry Pi 5 with Bookworm OS, we encountered the 500 Internal Server Error. Troubleshooting Steps1)Check NGINX Error Log: We began our troubleshooting by examining the NGINX error log located at/var/log/nginx/error.log.Here, we discovered error messages indicating issues with serving files. 2)Permissions Adjustment: Following online solutions, we tried adjusting permissions for our application build directory using commands like: sudo chown -R pi:www-data /home/pi/RDVI-frontend/build/ sudo chmod -R g+r /home/pi/RDVI-frontend/build/ sudo systemctl restart nginx Unfortunately, this didn't resolve the issue. 3)Permission Change to Root User: Next, we attempted changing permissions to the root user: sudo chown -R root:root /home/pi/RDVI-frontend/build/ sudo systemctl restart nginx Solution4)NGINX Configuration Update: Realizing the issue might be with the NGINX configuration,

Flutter Dart: Flutter 3D Buttons: https://medium.com/flutterpub/anatomy-of-material-buttons-in-flutter-first-part-40eb790979a6 Flutter Latest news: https://medium.com/flutter/two-months-of-fluttergoodnewswednesday-a12e60bab782 Build flutter app: https://www.youtube.com/watch?v=x0uinJvhNxIhttps://flutter.dev/docs/get-started/codelab Flutter toggle color after click: https://stackoverflow.com/questions/50863681/flutter-how-do-i-toggle-the-color-of-a-raisedbutton-upon-click Flutter on codePen: https://codepen.io/flutter Flutter gridlist examples: https://flutter.dev/docs/cookbook/lists/grid-lists Fetch data from server in flutter: https://flutter.dev/docs/cookbook/networking/background-parsing https://medium.com/flutterdevs/parsing-complex-json-in-flutter-b7f991611d3e UX Design in flutter: https://uxdesign.cc/flutter-design-challenge-onboarding-concept-1f5774d55646 Get the data from API: https://medium.com/flutter-community/parsing-complex-json-in-flutter-747c46655f51 Flutter time series: https://stackoverflow.com/questions/51739064/flutter-json-and-time-series-charts Flutter dart packages: https://www.w3adda.com/dart-tutorial/dart-packages Flutter dart introduction: https://www.w3adda.com/dart-tutorial/dart-introduction https://openlibrary.org/works/OL17556930W/Android_Fully_Loaded https://archive.org/details/unlockingandroid0000able/page/n5?q=Build+android+os Create mock server using postman: https://learning.postman.com/docs/postman/mock-servers/setting-up-mock/ Web Socket examples: https://www.websocket.org/echo.html Energy consumption calculator: https://www.rapidtables.com/calc/electric/energy-consumption-calculator.html Git hub basic course: https://www.udemy.com/course/git-and-github-crash-course-creating-a-repository-from-scratch/ Install svn on ubuntu: https://linuxtechlab.com/simple-guide-to-install-svn-on-ubuntu Flutter line chart,bar & pie chart: https://pub.dev/packages/fl_chart https://google.github.io/charts/flutter/example/bar_charts/simple.html https://www.digitalocean.com/community/tutorials/flutter-bar-charts https://github.com/imaNNeoFighT/fl_chart/blob/master/repo_files/documentations/pie_chart.md#sample-1-source-code Flutter list & grid view link: https://medium.com/@vignesh_prakash/flutter-listview-and-gridview-with-tabbar-221516518c75 Flutter Page color link: https://medium.com/flutter-community/a-deep-dive-into-pageview-in-flutter-with-custom-transitions-581d9ea6dded Flutter page control link: https://api.flutter.dev/flutter/widgets/PageController-class.html

STM 32 MCU and MPU Roadmap contains: 1. MPU (STM32MP1): - MPU with Arm Cortex-A7 650 MHz, Arm Cortex-M4 real-time coprocessor, TFT display, - Secure boot and Cryptography. - Combination of audio and real time processing with cortex A and M architecture. -STM32Cube AI tool running on cortex M4. - Camera and audio interfaces to simplify input device integration. Application: Used for real time and low power application and also graphic and communication high performance processing. Provide cloud based , making Smart home gateway with advance HMI and HD video. 2. High Performance MCUs(STM32F2, STM32F4, STM32FH7, STM32F7): These MCUs are available in single core as well as dual core. A7 type having large of flash and Ram is provided. STM32H7 having 280 Mhz embedding 2 MB flash ,1.4 MB RAM Application: graphics

JSON libraries 1.frozen Output JSON objects in C as JSON formatted strings and parse JSON formatted strings back into the C presentation of the JSON objects. FEATUES: • C and C++ complaint portable. • Several extra format specifiers supported. JSON token: This stucture contains- Pointer pointing to beginning of the value. Value length Type of the token Token types are string,number,true,false,null, object start, object end,array start and array end. API’s: • json_scanf Scans json string directly into c/c++ variables. • json_printf Print c/c++ variables directly into output stream. • json_setf Modifies existing json_string.

To Create any application in android we have to deal with three files: AndroidManifest.xmlactivity_main.xmlMainActivity.java AndroidManifest.xml: <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.login.login"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" />

Functionality: How to interact with activity,when a button is clicked,navigate from current screen(current activity) to another screen(another activity). Activity: In android,an activity is representing a single screen.Most applications have multiple activities to represent different screens.for example,one activity to display a list of the application settings,another to display application status. To Create any application in android we have to deal with three files: AndroidManifest.xmlactivity_main.xmlMainActivity.java AndroidManifest.xml <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.nav.navigation" > <application android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name=".MainActivity" android:label="@string/title_activity_main" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category

Here ,we are creating simple and basic functions calculator App. This app can help you to understand the layouts, buttons and action handling. To create this app we need to use different widgets such as TextView, button, EditText etc.This app is able to perform following basic four mathematical functions : AdditionSubtractionMultiplicationDivision To Create any application in android we have to deal with three files: AndroidManifest.xmlactivity_main.xmlMainActivity.java AndroidManifest.xml The AndroidManifest.xml contains information of your package, including components of the application such as activities, services, broadcast receivers, content providers etc. <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.calculator.calculator2"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name"

About Android USB Android supports USB devices through two modes: Android Accessory: In this mode external USB device acts as host.Android Host: In this mode Android Device acts as host and powers the external device. Manifest File for USB connection We want to be notified when an external USB device is attached to the Android device.This can be done adding a new intent filter entry to the Activity that should be started by the system when a USB device is plugged in. <activity ....... <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> <intent-filter> <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"