[OneWingedShark]

Start with a robust OS like any Unix based system: Linux or Mac OSX

Nope, you want OpenVMS¹... Security is not something that can be bolted on, and this is unfortunately the case with *nix systems.

Linux is only free if your time has no value.
[Jamie Zawinski]

¹ Actually what you really want is a formally verified OS, built by a formally verified compiler… which sadly doesn't yet exist.

[Uri’el-2012]

U-2012>Start with a robust OS like any Unix based system: Linux or Mac OSX

Nope, you want OpenVMS1... Security is not something that can be bolted on, and this is unfortunately the case with *nix systems. Linux is only free if your time has no value. [Jamie Zawinski]

1 Actually what you really want is a formally verified OS, built by a formally verified compiler… which sadly doesn't yet exist.

If memory serves me, VMS and later OpenVMS
was the DEC code stolen by Microsoft for NT which is Windows 8.

Unix on the other hand was developed by Bell Labs for DARPA
to operate successfully in a hostile enemy controlled network

[zeugma]

Linux is only free if your time has no value. [Jamie Zawinski]

That's so much crap it's not even funny anymore. As you can see from several above posts, Microsoft charges for their crap OS and then you have spend time and money to keep from getting drowned in viruses and trojans.

I'd agree with you that just about any version of VMS can be a robust and secure system. Not nearly enough userland software for it that I'm aware of though.