Test and evaluation of the SVID-compliant REAL/IX realtime operating system

The unique challenges encountered and techniques used in verifying the proper operation and performance of the REAL/IX operating system, a fully preemptive, low-latency operating system based on AT&T´s Unix system V release 3, are described. The current release of the system runs on a hardware configuration based on the Motorola MC68030 microprocessor. Extensions to the operating system provide facilities required by real-time applications, some of which yield the low interrupt latency and I/O system throughput required by real-time applications, such as: fixed-priority process scheduling; real-time permission control; resident program support through memory preallocation; high-performance common event notification; real-time timer mechanism; asynchronous, direct, and nonbuffered file I/O; connected interrupt mechanism; user-extensible kernel for device drivers and system services; and fast file systems. The testing effort confirmed the functionality of these features and their ability to provide real-time performance in applications. General system testing was also required to ensure that these new facilities had not inadvertently altered other standard functions