diff --git a/src/shared_mem_buffer.cpp b/src/shared_mem_buffer.cpp
index c76b0ea..d27ed07 100644
--- a/src/shared_mem_buffer.cpp
+++ b/src/shared_mem_buffer.cpp
@@ -1,7 +1,13 @@
 #include "shared_mem_buffer.h"
 
 #include <QDebug>
+#include <QFile>
+#include <QString>
+#include <QTextStream>
+#include <QDateTime>
+#include <QCoreApplication>
 #include <atomic>
+#include <algorithm>
 
 #ifdef QT_POSIX_IPC
     // The POSIX backend can be explicitly selected using the -feature-ipc_posix
@@ -9,33 +15,124 @@
     // macro will be defined. -> we use SystemV shared memory
 #error "QT_POSIX_IPC defined"
 #else
-#ifdef __linux__
+#ifdef linux
+#include <stdlib.h>
+#include <string.h>
 #include <sys/ipc.h>    // ftok
 #endif
 #endif
 
 //static bool shdMemFirstUse;
 
+static QString read1stLineOfFile(QString fileName) { // read for instance /etc/os-release
+    QFile f(fileName);
+    if (f.exists()) {
+        if (f.open(QIODevice::ReadOnly | QIODevice::Text)) {
+            QTextStream in(&f);
+            in.setCodec("UTF-8");
+            while(!in.atEnd()) {
+                return in.readLine();
+            }
+        }
+    }
+    return "N/A";
+}
+
 
 //QSharedMemory *SharedMemBuffer::getShm(std::size_t size) {
 QSharedMemory *SharedMem::getShm(std::size_t size) {
     static QSharedMemory shMem;
     if (size > 0) {
-#ifdef __linux__
-        //static const long nativeKey = ftok("/etc/os-release", 'H');
-        //static const QString fkey = std::to_string(nativeKey).c_str();
-        static const QString fkey = "0123456?000=7";
+#ifdef linux
+        static const long nativeKey = ftok("/etc/os-release", 'H');
+        static const QString fkey = std::to_string(nativeKey).c_str();
+        //static const QString fkey = "0123456?000=7";
 #else
         static const QString fkey = "0123456?000=9";
 #endif
 
+        qCritical() << __func__ << ":" << __LINE__ << ": size" << size;
+
         shMem.setKey(fkey);
         if (!shMem.isAttached()) {
             if (shMem.create(size)) {
+                qCritical() << __func__ << ":" << __LINE__ << ": created shared memory";
+
+#ifdef linux
+                if ((size != (std::size_t)shMem.size()) || (sizeof(SharedMem) != shMem.size())) {
+                    qCritical() << __func__ << ":" << __LINE__
+                                << "size=" << size
+                                << "shMem.size=" << shMem.size()
+                                << "sizeof(SharedMem)=" << sizeof(SharedMem)
+                                << "ABOUT TO REBOOT SYSTEM...";
+                    if (system("reboot")) {
+                        // reboot system -> shared memory re-created
+                    }
+                }
+
+                struct SharedMem *sh = (SharedMem *)(shMem.data());
+
+                memset(sh->indat_HWversion, 0x00, sizeof(sh->indat_HWversion));
+                memset(sh->indat_SWversion, 0x00, sizeof(sh->indat_SWversion));
+
+                memset(sh->os_release, 0x00, sizeof(sh->os_release));
+                memset(sh->date_of_creation, 0x00, sizeof(sh->date_of_creation));
+                memset(sh->creator, 0x00, sizeof(sh->creator));
+
+                QString const &os_release = read1stLineOfFile("/etc/os-release");
+                strncpy(sh->os_release, os_release.toStdString().c_str(),
+                        std::min((int)os_release.size(), (int)sizeof(sh->os_release)-1));
+
+                QString const &currentDateTime = QDateTime::currentDateTime().toString(Qt::ISODate);
+                char const *current = currentDateTime.toUtf8().constData();
+                strncpy(sh->date_of_creation, current,
+                        std::min((int)strlen(current), (int)sizeof(sh->date_of_creation)-1));
+
+                QString const &appPid = QString("%1 (%2)").arg(QCoreApplication::applicationName())
+                                                          .arg(QCoreApplication::applicationPid());
+
+                strncpy(sh->creator, appPid.toStdString().c_str(),
+                        std::min((int)strlen(appPid.toStdString().c_str()),
+                                 (int)sizeof(sh->creator)-1));
+
+                qCritical() << "os-release:" << sh->os_release;
+                qCritical() << "   creator:" << sh->creator;
+                qCritical() << "      date:" << sh->date_of_creation;
+
+#else
+                Q_ASSERT_X(size != shMem.size(), "compare sizes", "sizes different");
+                Q_ASSERT_X(sizeof(SharedMem) != shMem.size(), "compare sizes", "sizes different");
+#endif
                 return &shMem;
             } else {
                 if (shMem.error() == QSharedMemory::AlreadyExists) {
                     if (shMem.attach()) {
+#ifdef linux
+                        if ((size != (std::size_t)shMem.size()) || (sizeof(SharedMem) != shMem.size())) {
+                            qCritical() << __func__ << ":" << __LINE__
+                                        << "size=" << size
+                                        << "shMem.size=" << shMem.size()
+                                        << "sizeof(SharedMem)=" << sizeof(SharedMem)
+                                        << "ABOUT TO REBOOT SYSTEM...";
+                            if (system("reboot")) {
+                                // reboot system -> shared memory re-created
+                            }
+                        }
+#else
+                        Q_ASSERT_X(size != shMem.size(), "compare sizes", "sizes different");
+                        Q_ASSERT_X(sizeof(SharedMem) != shMem.size(), "compare sizes", "sizes different");
+#endif
+
+                        QString const &appPid = QString("%1 (%2)").arg(QCoreApplication::applicationName())
+                                                                  .arg(QCoreApplication::applicationPid());
+
+                        qCritical() << __func__ << ":" << __LINE__ << appPid << "attached shared memory";
+
+                        struct SharedMem const *sh = (SharedMem const *)(shMem.data());
+                        qCritical() << "os-release:" << sh->os_release;
+                        qCritical() << "   creator:" << sh->creator;
+                        qCritical() << "      date:" << sh->date_of_creation;
+
                         return &shMem;
                     }
                 }
@@ -43,6 +140,13 @@ QSharedMemory *SharedMem::getShm(std::size_t size) {
             qCritical() << shMem.nativeKey() << shMem.key() << shMem.data()
                         << shMem.error() << shMem.errorString();
             return nullptr;
+        } else {
+            qCritical() << __func__ << ":" << __LINE__ << "shared memory already attached";
+
+            struct SharedMem const *sh = (SharedMem const *)(shMem.data());
+            qCritical() << "os-release:" << sh->os_release;
+            qCritical() << "   creator:" << sh->creator;
+            qCritical() << "      date:" << sh->date_of_creation;
         }
     }
     return &shMem;