Hi, a geek used PC104 hardware to build a high altitude glider, and set up his choice on C for software, but he considered Ada. Does someone know about a usable GNAT/PC104-DOS cross? Laurent http://members.shaw.ca/sonde/index.htm http://members.shaw.ca/sonde/software.htm << [...] What Language / Platform? Initially I started out with a "white-paper" attitude, looking for the platform with the best reputation for developing reliable, real time systems. Over time I came to realize that there is a tension here between prestige and practical performance. An Ada / Unix based system would seem to be the ideal - the most virtuous. But Ada's structure and design-for-reliability approach is burdened by poor support on "civilian" platforms, and in particular a very large instruction set that, in the view of many experts in the field, hinders its in-practice suitability for reliable systems, no matter what its reputation is. Unix, as well, is not very available for 16-bit embedded systems, and 32-bit systems are too battery-hungry. What I settled on was using an old language, C, in a rigorous way. C++ was put aside almost immediately, as a language extension that just isn't defined, clear or stable enough for a high-reliability system to be worth its benefits. The operating system used is nominally DOS at both ends, as I have no faith in the stability of Windows. As the industrial PC-104 uses a dos-rom operating system, that also provides machine-code level compatibility between the software modules and data structures both in the aircraft and on the ground. This would also put a higher burden on the practices used, instead of reliance on the reputation of a language to provide quality. It turns out that many established high-reliability system developers take this approach, where reliability largely rests on programmer practices and rigorous static-checking. Automatically-verifiable standards have been developed, such as MISRA-C, to ensure reliable, fail-safe end products with the C language. The book Safer C - Developing Software for High-Integrity and Safety-Critical Systems, has also been a great help, as have numerous websites (most of which I've since lost track of), on developing good programming practices. [...] >>