Stratus' server figures are the latest to come out of a competition between companies such as Sun Microsystems, Microsoft and Hewlett-Packard to achieve "five-nines" reliability--servers that work 99.999 percent of the time, or spend less than 5 minutes per year on the blink. Different companies have laid claim to the coveted five nines over the years. But one company's results are often disputed by another company, owing to factors such as which software is running on the tested servers.