I thought trying out ArcGIS Server on Linux would be an experiment worth undertaking. I saw this post about installing on Ubuntu, which I already have running on an older PC. But I was curious how Ubuntu compares to Red Hat, the server edition of which (Red Hat Enterprise Linux) is listed as a supported platform for AGS on the ESRI website. Fortunately, rather than paying for Red Hat Linux, there is CentOS. The free version of unfree RHL. I thought I’d simply download the latest version (5.4) and install it on my #2 PC. That, however, didn’t work because apparently the Intel Celeron PGA478 does not support Physical Address Extension (PAE ), whereas Centos 5.4 does. I couldn’t quite figure out starting with what version a PAE-kernel is included, and I didn’t want to get into the nitty gritty of switching out the kernel or compiling one myself. Ergo no luck. So I will try installing version 4.8 instead. Interestingly, I’ve never had any trouble like that with Ubuntu, which has installed out of the box on the Celereron, an even older Celeron, and my Lenovo laptop. So, if version 4.8 fails, I will install AGS on Ubuntu.