Explore a comprehensive analysis of QNX, a proprietary real-time operating system for embedded systems, widely used in critical devices across various industries. Delve into the intricacies of QNX's microkernel architecture, IPC message passing, attack surface, and security history. Examine the boot process, memory layout, user management, and process limitations. Investigate the quality of QNX's security-oriented PRNGs and exploit mitigations, including DEP, ASLR, stack canaries, and RELRO. Discover vulnerabilities such as rootless execution, Qnet EOP, and various information leaks. Compare the security features and weaknesses between QNX 6 and QNX 7, gaining valuable insights into the operating system's evolution and potential attack vectors in embedded systems.