I'm currently looking for a uninterrupted power supply that will assist me in safely shutting down my two new PCs (One server module for holding data and one desktop PC for... well... using). I'm mainly worried about the server considering it'll be constantly reading and writing (Main issue, writing) data & moving items between drives, the last thing I want is my drives failing. I'm currently attempting to find a UPS which has the ability to:-
A. Keep the server (And maybe PC (A hell of a lot less of a priority, but, I'd still like to keep it safe)) on for ~ 5 minutes
B. Issue a TCP packet to certain IP addresses when the power is cut (Both WAN and LAN. LAN to call a program I'll code later that simply shuts programs in the correct way & closes down, and WAN to inform me that it's happened, so, I can come home to fix it. If WAN isn't possible, then, I guess I can have the computer issue that request when it receives the LAN packet) and when the power is regained (A 'magic packet' (Wake on LAN)), because, I may or may not be in the city at the time and I'll want to be able to SSH/VNC back into my boxes to check everything is fine.
C. Switch fast enough so that the server/desktop doesn't shut down.
However, what I need to know is how long a computer can stay powered without power? I see a UPSes with all kind of 'switch times' (From ~ 5MS to 50MS). So, I obviously don't want it to shut down my PC, then provide power after it's already down. How long can the average PC last without power?