Despite their flexibility, most PTV systems ship with small storage capacities-the largest so far is 60 hours. Keep in mind that this storage capacity is at the poorest recording quality (e.g., a 60-hour unit has slightly less than 18 hours of storage capacity at the best recording setting). Although these recording times might seem like a lot when you compare them with a standard 6-hour VHS tape, you can't pop out the PTV's hard disk when it's full. Put another way, imagine you only had 10 VHS tapes and you couldn't go out and buy any more-ever. When you wanted to record something new, you'd have to delete existing recordings you might otherwise want to keep. Check your shelves; if you've got more than 10 tapes, even the biggest TiVo will space-constrain you, too.

Not wanting to jump in until others had resolved the recording time constraints, I resigned myself to wait for prices to come down and capacities to go up. However, I soon found out about a group of enthusiasts who had found a way for almost anyone to expand their TiVo system to previously unheard of capacities. Folks were gaining more than 80 hours. Of course, the downside of this process was an immediate voiding of the warranty. (That information bears repeating: Opening your TiVo will void your warranty! Consider yourself duly warned.)

Convinced the time had come to take the plunge, I bought the cheapest Philips 14-hour TiVo. Despite the device's low recording capacity, I had a method to my madness. For starters, you currently can't upgrade the dual-drive units, and because some 30-hour models ship with one hard disk and others with two, I decided not to try to figure out which ones were which. I ascertained this information from a TiVo hacking FAQ and have since found several outstanding Web sites for everything you'd ever want to know about hacking the TiVo-for more information on these resources, see the Related Resources at the end of this article. Another reason for buying the cheap device: if I broke the darn thing, I'd be out less money. (You can also upgrade Sony TiVo devices.)

A Few More Caveats
You can either modify a brand new TiVo or upgrade a unit that's already in service. There are drawbacks to each approach. When you back up a brand new, never-configured TiVo hard disk to disk or tape (some folks later burn a copy of the drive's image onto several CD-Rs), the disk's data will take up much less storage space than one that's been in use. However, because I'd read that lots of people were reporting modem problems with their TiVos, I decided to test my system first. I had another reason, too. My older system shipped with the 1.3 software release, and I wanted to install the current 2.0.1 release on my backup copy.

So why did I back up my TiVo drive in the first place? Well, there were several more hurdles to overcome before I'd have a working system, any one of which could result in trashing the TiVo's data. The safest way to avoid tragedy is to first create a backup image of the original hard disk. Some folks do this by purchasing a second drive just to copy the original to and store the original A drive on a shelf. This is the safest approach. (In TiVo parlance, the A drive is the primary hard disk, and the B drive is the secondary hard disk that I'll be adding.)

To upgrade my TiVo, I followed one of the most common methods, which uses a separate PC, Dylan's Linux boot disk, and Mike's BlessTiVo program to facilitate backing up the original drive's data and new B drive initialization. (Who are Dylan and Mike? To find out, check out the TiVo hacking FAQ in the list of Related Resources.) If you've come this far and still aren't afraid of turning your TiVo into a doorstop, I'll begin.

Getting Busy
First, I unplugged the TiVo-The power supply is completely exposed, and I didn't want to be poking around inside a live box with metal objects. Using a number 10 Torx screwdriver, I removed the three screws on the back of the unit, slid the top cover to the rear, and lifted it off. Next, I removed the IDE and power cables from the drive and removed the two Torx screws at the front of the drive-mounting bracket. After sliding the drive/bracket assembly slightly to the rear-to clear the positioning tabs-I was able to lift the assembly out.

I opened my PC, connected the original TiVo drive to the secondary IDE channel, and attached my temporary storage hard disk to the primary IDE channel. Next, I booted the PC and made sure that the BIOS saw both drives and registered the correct sizes for both hard disks. This step is very important because the BIOS in some older PCs doesn't properly register the newer, larger drives. I used a 3.5 DOS boot disk to format my temporary storage hard disk as FAT32. I rebooted using Dylan's Linux boot disk and logged in as root. Finally, I was ready to back up the original TiVo A drive. Following the hacking FAQ, I entered the following at the command prompt:

mount -t vfat /dev/hda1 /mnt

This command created a temporary place for me to redirect the disk image. Next, I typed the following at the command prompt:

dd if=/dev/hdc bs=32k | gzip -9c > /mnt/tivodisk.gz

This set of commands copies the original TiVo A drive block by block, compresses the information, and outputs it as one file to the temporary storage hard disk. At this point, all I could do was sit back and wait. Other than the indicator lights on the hard disk, this backup process does not provide any status indication to ensure that the backup is working properly, so I left to find something to occupy my time. After a couple of hours (your mileage will vary), the screen showed this cryptic message:

kernel BUG at file.c:79 
Segmentation fault
5039+0 records in
5038+0 records out

This response wasn't what I'd hoped for. I tried again, this time changing to a lower gzip compression value, but I encountered the same problem. Guessing that the problem might have to do with qzip not being able to handle files larger than 2GB in size, I decided to take a different approach. I swapped the drives around on their IDE channels, installed Red Hat Linux 6.1 on my temporary storage hard disk, and issued the following command to try backing up the TiVo drive image again:

dd if=/dev/hdc bs=32k of=/tmp/tivodisk

Hurrah! I got the results message I was looking for:

13066+1 records in
13066+1 records out

Unfortunately, my excitement turned to disappointment later on when I discovered that this wasn't a complete backup either. Eventually, I found out that the root of my problem stemmed from the Linux kernel's maximum file size limitation of 4GB. I needed to use the split command to break the output file into several smaller chunks, like this:

dd if=/dev/hdc bs=32k | gzip -9c | split -b 650m - /mnt/tivodisk_

Backing up to the FAT32 partition this way would have worked fine. In case you're wondering why I didn't just use a utility such as Ghost or Partition Magic to copy the drive, the answer is simple: The TiVo disk has some nonstandard partition types, several of which are byte-swapped, and those utilities can't handle these conditions. (Ghost 7.0 is reportedly now able to copy TiVo drives using raw mode.)

With my backup complete, it was time to bless (i.e., format) my new 60GB TiVo expansion B drive. I connected the hard disk as the secondary master and booted Dylan's 3.5 Linux disk once more. Next, I entered Mike's command to bless the new drive:

BlessTiVo /dev/hdc

Photo 1: Viewing the TiVo chassis after cutting the bottom cable tie.

The program gave me a chance to double-check that I was operating on the correct drive, and voila, the hard disk was ready to use. A confirming message also told me that the BIOS correctly recognized the drive's size.

Moment of Truth
Now I could move on and try my handiwork. I set the jumpers on the expansion disk to the slave setting and took both disks back to the TiVo. After cutting the plastic cable tie that held the second power cable to the bottom of the chassis, as Photo 1 shows, I reinstalled the original hard disk. Unfortunately, I had no way to mount my new expansion drive. I set the drive on top of a piece of cardboard temporarily to keep it from shorting to the chassis and connected the IDE and power cables to both drives. The moment of truth had arrived. I turned on my TV and plugged the power cord into the TiVo. After my TiVo was fully initialized, I opened the Messages and Setup menu and checked the System Information screen. Wow, the Storage Capacity line showed 89 hrs, 52 min (Basic Quality); more importantly, in Best Quality mode, I had nearly 26 hours of record time. Success!

Photo 2: Attaching the 9th Tee Enterprises mounting brackets to the new hard disk.

With the top off the TiVo device, I was very cognizant of the increased noise level from operating two disks, and I began to wonder whether it would be objectionable after I closed everything up. After I put the cover back on, the sound was noticeable up close, but when I returned to my normal couch spud viewing position, I could just barely hear the TiVo in a quiet room. The fan did run more frequently though, an inevitable byproduct of the extra heat generated by a second disk.

That's a Wrap
The last step in the process was to permanently mount the new disk. Fortunately, I found plenty of postings about disk mounting in the Underground section of the AVS TiVo Forum. Here I found 9th Tee Enterprises, a company that makes a standard-looking bracket, as Photo 2 shows, for just this purpose. I bought one immediately. When it arrived a few days later, I bolted the new disk to the bracket and installed it in my system, as Photo 3 shows. At last, I could replace the top and button up my system, this time for good.

Photo 3: Viewing the TiVo chassis with the new hard disk in place.