A DVR Security System That Isn't Based on Windows?

Brady J. Frey asks: "For months, I've had a client that has been looking for a Linux or Mac alternative for their DVR Security systems. They are a large Real Estate company with 200+ cameras world wide, and their Pelco PC DVR's are hubs for viruses. These systems cannot run anti-virus software at the same time they record -- but require internet inbound/outbound traffic through specific ports that leave some nice holes in the firewall for viruses to find their way in as needed. Yes, we could put up a server in front of each, or a router that has anti-virus built in, however this is not a cost effective method for a number of their locations. Therefore we are looking for alternatives. Any suggestions?" "We've tried looking at Ben's Security Spy for Mac, and running a Quicktime server, but it was not industrial enough for us and the developer has been elusive. We're looking at Endura by Pelco, but there's some questions unanswered for it.

What I want is a high end, professional DVR system for a large business that does not run Windows. Budget isn't really an issue at this point, since we are just looking for options.

To note, I'm hearing I could possibly do IP cameras, and host any ol' web server I want to download those files, but I have no clue as to how to control the cameras, or if this is really a possibility. Any advice or information is appreciated. If you are an expert in this industry, we may have a need for your services and would welcome that too!"