My vote is for Windows XP Service Pack 2.
Unlike previous service packs, Service Pack 2 (SP2) added lots of new features to Windows. Some examples:
- Improvements to Windows Firewall and made it enabled by default
- Data Execution Prevention to make buffer overflow attacks much harder
- Popup blocker in IE6
- WPA encryption for Wi-Fi
Those first two items probably did more than anything in all of Microsoft's history to make Windows secure. Before XP SP2, the security situation on Windows was just embarrassing, and the number of Windows zombie machines was huge.
Ever since Windows XP SP2, you've been able to run a fresh Windows installation out-of-the-box without installing anti-virus software and be pretty much safe against your computer suddenly becoming a zombie in someone's botnet.
That's a big deal.
...
There are probably dozens of safety critical bug fixes to fly by wire systems on commercial airliners that probably should be the most important, but I don't know of any specific ones, and those that know, won't say. (Would you?)
So, I'll go with the changes to compression and communication that saved the Galileo space probe mission to Jupiter and its moons. The mission cost US$1.4 billion, took six years to reach the Jupiter system, and went on to do amazing planetary science for over eight years, despite a failure of one of its most fundamental systems, which should have rendered it stillborn.
The main antenna failed to open properly, but clever reprogramming enabled the capacity of the low gain antenna to be increased eight times, enabling 70% of the mission objectives to be completed. Just think of the distance involved. There was not going to be a Shuttle flight to fix this problem.
They also had problems with the digital tape recorder, which were an even more amazing remote fix, but these were more remote control work-arounds to fix hardware issues rather than software patches.
More here: http://en.wikipedia.org/wiki/Gal...
Matt Langley is the Founder of http://www.icelimited.co.uk/ and developer of http://dresscodeguide.com/ and http://AndThat.net/.
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