Q: Actual computer operating time

I doubt that your date range is possible (could be wrong, I guess) - you can get uptime and reboot history > http://osxdaily.com/2009/09/22/check-your-macs-uptime-and-reboot-history/

One of the things to realize is, when the battery goes completely flat, the Date and Time

may fail to be in the correct year, month, or day. In some instances, the default date is a

matter of record (sometimes years before the build date of the model of your computer.)

For shorter durations you can account for, there may be a source to get a widget such as

the one offered by the original iStat Pro (version 4.x) which is hard or next to impossible

to get. I have and use iStat Pro in my PowerPC G4 Macs, portable & desktop; also in early

Intel based Macs.

I have a link to get the original iStat Pro that works in older Macs...

http://mac.majorgeeks.com/files/details/istat_pro.html

{I've tried this link in the past few months; seems to be stable, choose one of the mirror links

with the arrows; open the resulting file in computer you want to use it in; save to USB flash.}

This widget will count the up time or runtime, then starts over on restart; which is OK for

a desktop model that may have a backup power supply (UPS) and would be allowed to

sleep when not in use. I've had desktop Macs with an uptime of over 8 months without

a restart. The most stable was a PPC G4 model running Tiger 10.4.11; and that was a

clean installation with only the latest updates added. That avoided interim issues that

appeared in the days it was new. A recent installation now would be 1) install DVD, 2)

combo Update, 3) security Update, 4) application Updates, 5) TenFourFox browser.

So, on restart the records get wiped; the system clock itself would go back to when the

operating system first booted. This record may be changed or corrupted due to power

failure, main power battery, PRAM battery or backup capacitor failures. And the record

may not survive the Console logs that get stored on a hard drive. Unless you happen

across some advanced utility for diagnostic that could read information flashed on chips.

But that may not store incremental updates over the life of the product either.

Not sure now, if a product such as OnyX (from Titanium Software, free utility) could let

you find the system runtime. It does several things and I have versions of it in older Macs.

http://www.titanium.free.fr/onyx.html

Why do you seek to keep track of or find record of this activity?

Good luck & happy computing!