eSATA functionality

[Narf54321]

As every Tivo Series-3 owner knows, there is an external-SATA interface port on the back of the S3 unit. I was just poking around the StageA bootup directory on my S3 (software v8.0.1c), trying to verify the kickstart codes for another post. And this is what I found on my S3:

  echo "Kickstart code 6 2 - initialize E-SATA drive"
  do_esata_init=1

Very interesting. I wonder if Tivo has gotten hard drive divorces built into the system software, yet. There are a few telling splash images in the /tvbin directory.

[Jamie]

I wonder if Tivo has gotten hard drive divorces built into the system software, yet. There are a few telling splash images in the /tvbin directory.

It's at least partially there. Try preparing an A+B drive using mfstools then plug only the A drive into the Series 3. You'll get the "LostDrive" screen, and if you proceed it will reconfigure it as a single drive system. Of course, that's a simple case where the B drive is added, but nothing is on it yet. They may not yet be dealing with the case of a populated B drive.

Anyone with a Series3 tried to hook an esata drive up? What shows up in the kernel log?

[Robre]

Hi guys,
I'm looking at getting one of these new boxes. But gee - with HD content I'm back at the hours where my old Tivo was 4 years ago. This eSata interface might really have potential. Has anybody been inside the S3 close enough to see what eSata disk controller chip they put on the motherboard. Tell me the manufacturer and model number and I might be able to shed some light on Tivo's future storage upgrade strategy.

Also (Narf54321) wrote "I wonder if Tivo has gotten hard drive divorces built into the system software, yet. There are a few telling splash images in the /tvbin directory."

Can you tell me a bit about these splash images? What are they "saying".

[Robre]

In regards to the splash screen - Found them. Thanks.

[Narf54321]

Also (Narf54321) wrote "I wonder if Tivo has gotten hard drive divorces built into the system software, yet. There are a few telling splash images in the /tvbin directory."

Can you tell me a bit about these splash images? What are they "saying".

Tivo uses a proprietary drive format and partitions known as MFS. The older model Tivos (which were IDE-based) coud usually support two drives, which would be "married" together. The problem being that, because you couldn't "divorce" the drives, if either drive failed you pretty much lost all your recorded shows and had to restore from scratch.

With this new external eSATA connection, if it is ever activated, it presents opportunity to add or remove an external drive. Removing a "married" drive is problematic, which is why I was curious if Tivo finally added official "divorce" support when you unplug an extra drive. The splash images (for on-screen display) seem to indicate they're at least thinking hard about it.

Anyway, testing this is still on my To Do List, especially as I have a shortage of extra SATA drives.

[Robre]

I'm on the same track - they seem to "plan" to do something different and they also have to consider some FCC "rule" that you can't take content away from a "closed" Tivo (kind of a DRM). They needed to do that to not get sued out of business (remember Replay).
Short of having access to an open S3 - can you could tell me what disk controller chip they are using. If it is what I guess it is I can tell you how they are going to make this work. I need the manufacturer and the model number. Picture of the area where the drive cables are connecting to the board would help too. - Thanks in advance.

[Jamie]

Short of having access to an open S3 - can you could tell me what disk controller chip they are using. If it is what I guess it is I can tell you how they are going to make this work. I need the manufacturer and the model number. Picture of the area where the drive cables are connecting to the board would help too. - Thanks in advance.

The SATA controller is onboard in the bcm7038 chip. Lots of high res photos here. This one may have the detail in the area you want.

[bcc]

The SATA controller is onboard in the bcm7038 chip. Lots of high res photos here. This one may have the detail in the area you want.

The source code for the driver is even on tivo.com. It doesn't look like it supports hot-swap like the latest esata controllers do.

From those splash screens, it looks like tivo is planning pretty rudimentary support of esata drives (you can't divorce without having recordings deleted on you). For folks who already know how to upgrade internal drives, the esata support doesn't seem like much of any benefit.

[Robre]

Thanks, Jamie - the BCM 7038 is a Dual HD Video chip. I'm still scanning the images and I can't find the ESATA controller. Do you know what's under the heat sink? Is that the main processor that runs the box or ... I see the traces from the internal sata drive running toward it.

[Jamie]

Thanks, Jamie - the BCM 7038 is a Dual HD Video chip. I'm still scanning the images and I can't find the ESATA controller. Do you know what's under the heat sink? Is that the main processor that runs the box or ... I see the traces from the internal sata drive running toward it.

Read the spec sheet I linked to -- the bcm7038 is an all in one chip and includes the SATA controller. The bcm7038 is what is under the heat sink and is the main processor, the mpeg2 decoder, the SATA controller, the usb2 controller, etc, etc. Again, read the datasheet.

[Robre]

Thanks - I was hoping to find a dedicated chip. In this case I can only speculate how they might try to manage the external eSata drive. Check out this site: http://www.siliconimage.com/products...ct.aspx?id=108

Look at the diagram of the storage processor and then download the White Paper Capacity Expansion. Tell me what you think.

[Jamie]

Look at the diagram of the storage processor and then download the White Paper Capacity Expansion. Tell me what you think.

It sounds like they've basically put logical volume management onto the controller chip.

I don't see how any of that driver virtualization stuff helps on the tivo. Whether the drive(s) appear as one aggregate virtualized drive, or individual drives doesn't really matter. Either way, the tivo needs to expand or contract it's Media File System (MFS) in response to drive additions, subtractions or size changes, and there is no way the drive controller chip is going to do that for it given that the file system is a custom proprietary TiVo file system.

I suspect it wouldn't be that hard for a hacker to get eSATA working on the S3 if they really wanted to, in the same way that dual drives currently work on the S2. It might mean a custom kernel, and/or some tivoapp patches.

[Robre]

Future will show. IF Tivo would have used the SI chip I know the drive addition would be transparent. W/o the Tivo has 250 GB space and with an "appropriate" (maybe they except any eSata) external drive the Tivo would see 1 T. With the Broadcom chip doing it all - including Sata management - we have to see. Maybe they [BC] licensed the technology. I'll be watching the development very closely. Tivo might also have changed their file system that manages file access. If they have found a better storage system that gives them size AND file locking AND keeps the networks happy they will switch to that tech.

[Narf54321]

I don't think Tivo is ready to ditch MFS anytime soon. Most likely, to appease the CableLabs folks, they'll keep the recording meta-data on the internal drive while allowing the raw data of the actual "show" to be on the external device. All the info for finding the right chunks would be stored on the internal drive partition(s).

Anyway, I believe Jamie has mentioned before the hard limit of MFS is about 2TB. The practical limit seems to be closer to around 1TB, based on some of the Tivo "RAID" projects I've read about.

Drives are going to reach 1TB this year, so anyone willing to replace the internal S3 hard drive will max out the box. At that point, worrying about the eSATA port may be moot.

[Jamie]

IF Tivo would have used the SI chip I know the drive addition would be transparent.

Not without a complete redesign of their file system.

If they have found a better storage system that gives them size AND file locking AND keeps the networks happy they will switch to that tech.

The have the equivalent of drive locking via the crypto chip. All A/V data written to disk is encrypted and tied to the crypto chip in a specific box. There are size limitations inherent in the current MFS file structure. The MFS limit is 2TB. Some have said that the kernel limits a single drive (logical or physical) to 1TB, but may people run dual 750GB drives on S2 tivos. Eventually the size limitations inherent in the file system will have to be addressed.

Making the content providers and distributers happy is a whole 'nother ball of wax. Has Silicon Image recieved CableLabs certification for their device?