Herman Oosthuysen, GPL, 2005
It is puzzling to ordinary folks why UNIX users do not want to use anything else and why they don't want to help them with their Windows problems. UNIX administrators usually know Windows very well too, because Windows is part of the computing environment and like weeds, these machines grow everywhere. Many admins, like me, have done Windows and Exchange server administration courses, yet UNIX admins almost universaly avoid Windows like the plague.
There really are only three reasons why:
1. Security
2. Efficiency
3. Stability
A UNIX machine can run for several years, until the hardware eventually fails, with zero maintenance and no restarts. My previous Red Hat Linux web and mail server ran for 4.5 years. The present one has now been going for almost 2 years:
-bash-3.2$ uptime 23:25:45 up 567 days, 10:32, 2 users, load average: 1.08, 1.02, 1.01
This machine is quite busy. It processes and discards about 10,000 spams per hour and it also serves a few small web sites on the side.
UNIX machines are as reliable as refrigerators. Windows machines need constant care and feeding and if you would leave one alone, then it will die a horrible death in less than a year and then you have to completely wipe and re-install the system to get it going again, so you ignore a Windows machine at your peril.
In terms of network performance, a Linux machine is about twice as fast as a Windows machine. Windows machines slow down over time due to disk fragmentation and other detritus in the NTFS file system. Linux file systems do not suffer from that problem and performance remains constant over time, year after year.
For server farms, this makes a big difference, since one typically needs only half as many Linux machines to do the same thing and a Linux administrator can handle five times more machines than a Windows administrator (since the tools are better and the machines need less attention). Therefore a Linux based server farm needs half the hardware and one tenth the people compared to a Windows based equivalent. The large data centres run by Amazon, Rackspace, Yahoo and Google, would be impossible with Windows machines, since they would be too expensive to operate.
For email processing, the difference is even more striking. One can literally replace a ten server MS Exchange cluster with a single Citadel or Yahoo mail server. The reason is that MS uses a very old and limited performance database in Exchange. Exchange constantly bumps against a 16 Gigabyte limit (update: 75 GB since 2008), while Citadel has a 256 Terabyte limit (so it is only limited by disk space).
UNIX machines have legendary security. A default installation of UNIX does not require firewalls and anti-virus programs. UNIX anti-virus programs do exist. They are used to scan email and files for Windows viruses in order to protect Windows based client machines. Most firewall devices actually run Linux and likewise, the main reason for their existence is to protect Windows machines.
The reasons for the superior security is many fold, but it all revolves around access control. The National Security Agency developed a Mandatory Access Control system called SELinux, which is now part of the Linux kernel as maintained by Red Hat. Novell and Ubuntu uses AppArmor and Mandriva uses Tomoyo, these programs are older and do the same thing, but there are also Netfilter, TCP Wrappers and ACLs. Windows has ACLs, but apparently it doesn't work well enough.
The result is that one can set up a large number of UNIX machines and then forget about them and hit the beach or go do something more interesting, which is altogether a better life than fixing the same problems over and over again on a bunch of Windows machines and then restarting them after each fix.
However, most UNIX admins can be bought with beer, pizza or doughnuts, so if your Windoze puter is on the blink, all isn't lost...