Here's the detailed upgrade story complete with photographic documentation, if anyone cares.
It was a slightly shitty ordeal and it would have gone smoother if I had read the fine print that I wasn't supposed to use a computer running Windows XP for the upgrade. This added about an hour to my total upgrade time of about 2.5 hours.
Here is a shot of my initial system info so you can see that I have nothing up my sleeve:
Which is 35 hours for the 40GB drive that it ships with. Thing I found out was that almost all Tivos have room for 2 drives, and in my case, it has the extra mounting points readily available. So I yanked the original drive and plugged it into Heather's computer (poor Heather):
This is where I ran into snags. You're sposed to back up the contents of your original TiVo drive to your PC hard drive, but what I failed to pay attention to was the fact that you need a filesystem (called FAT32) that Win 95/98/ME run. Windows NT/2000/XP will not work. So I freaked out for a bit and thought I ruined my TiVo, but it turned out okay. Only problem was that I needed a drive with FAT32 on it, and the only computer in the house with that is the Rosstation, which is the biggest pain to mess with. But I did it:
Actually the first drive I pulled out (the Rosstation has three) didn't work either, which freaked me out even more, but I eventually got one that worked. I gave the command (you boot your PC to a startup CD and run Linux commands on it) to backup the original drive to the Rosstation drive, and it created a 1.3GB backup (uncompressed). With that done, I took that backup and "restored" it to the new 120GB drive. That only took about a minute. Then I plugged it into my TiVo to test it:
It worked fine, it was as if I was using my original TiVo, except the recordings, although listed, were not backed up - only my system settings. Now it's time to tell the original drive that he has a larger brother. I plugged the new drive back into Heather's computer, and ran one more command to notify the original drive of that the new one was going to be in use. Then I popped them both out and slapped them onto the TiVo mounting bracket:
Here they are in the unit:
It was a tight fit with the new larger IDE cables but I managed to get it in there after some fiddling. Plugged the pup back in, wait for what seems like an eternity for it to warm up and reacquire the satellite signal, and BAM, the system is up and running, reporting a whopping new capacity of 146 hours! I'm not exactly sure what the time-to-storage ratio is, but 146 hours is plenty for Heather and I.
As I type, I hear Heather clicking around on the new beast, undoubtedly adding all kinds of crap to the to-record list, such as A Wedding Story and Trading Spaces. Such is the price of greatness, my friends....