The more stable and secure Windows NT v4.0 is the 32 bit OS of choice. Some Unix buffs insist that Windows NT is not capable of handling the real-time environment of integrated navigation systems. A single display that crashes in such a system is not going to bring all navigation to an abrupt halt. As is well known, hard reboots, line aborts, and circling up to restart the survey line have cost considerable downtime in the past. Quality control in software development is important.
Buggy software is everyone's nightmare, whatever the field of endeavor.
It makes sense to audit the company from which software is purchased. Choosing software developed under a quality control standard such as ISO9001 is wise. While nobody is crazy enough to guarantee absolutely bug-free software, at least ISO certification offers some assurance that the software has been thoroughly and continuously tested during development and is less likely to contain bugs serious enough to bring a survey to a grinding halt. Potential buyers should insure that the INS software is limited only by the amount of RAM and processing power available, and not by the software itself. These days it is not uncommon to interface a large number of different sensors simultaneously.