# Swappable Internal Harddrive



## socrplyr (Jul 19, 2006)

I have been thinking about this for quite a while and just finally decided to post my suggestion.

The next Tivo iteration should have a swappable internal hard drive (easily done with a small door in the back). The system would work like this. There is some sort of flash memory internally in the Tivo. This memory will contain a small basic OS that will be able to Scan/Fix/Diagnose HDD Errors and Download the full Tivo OS to the HDD (for the case of replacement drives) from the internet. This would allow Tivo to "repair" failed drives remotely (by just sending a replacement). It would also allow the user to get a Tivo approved drive and upgrade storage without an external device. There are varying levels at which the OS on the flash could be (from just a simple thing that does what I suggested to the full Tivo OS and the drives used only as storage).

This would reduce Tivo Support and Warranty costs while providing a more upgradable machine.


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## classicsat (Feb 18, 2004)

It would be costly (but not totally expensive) to implement, both in the drive bay, adding the Flashboot, as well as support costs for the scheme. The content owners might have something to say, especially when it comes to Cablelabs approval.

Practically it can be done. Flash is cheap now (you wouldn't need more than 4GB), and SATA drives work fine in a bay.

The PROM chip would try to boot the drive, and if it fails it would boot the Flash drive, which would run further tests to see if it is an empty drive, or what has failed and needs installed. The Flash drive would hold its boot/kernel/root (OS/application), and images for the factory OS version, the last two OSes (boot/kernel/root), and the root Database.

A system needs to be implemented to keep the current drive signature, so that if the drive is changed, the old drive becomes invalid, so if it re-inserted, it is treated as new. This would be to prevent people from collecting drives with recordings on them.


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## lrhorer (Aug 31, 2003)

socrplyr said:


> I have been thinking about this for quite a while and just finally decided to post my suggestion.


It's not exactly a new one. We've seen variations on it before.



socrplyr said:


> There is some sort of flash memory internally in the Tivo. This memory will contain a small basic OS that will be able to Scan/Fix/Diagnose HDD Errors and Download the full Tivo OS to the HDD (for the case of replacement drives) from the internet.


There is no need for this level of complexity, and no reason to host the OS on the hard drive. The full Tivo OS is quite small. The bootstrap partitions are only a single sector, the kernel partitions are only 4M each, the root partitions are only 256M each, /var is only 256M, and the swap is usually only 128M. All totaled it's less than 1G, although depending on the memory type, it might be a good idea to copy the /var partition to the hard drive and keep the swap area on the hard drive, as well. Flash memory only supports a limited number of write cycles.

The big problem with this from my perspective is it would make it much more difficult to modify the OS, and many of the best features of the Tivo can only be unlocked by modifying the OS.



socrplyr said:


> This would reduce Tivo Support and Warranty costs while providing a more upgradable machine.


I'm not so sure it would save them support or warranty costs in the long run, and the machine would be less upgradable, not more. It would be trivially easier to swap hard drives, is all.


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## lrhorer (Aug 31, 2003)

classicsat said:


> Practically it can be done. Flash is cheap now (you wouldn't need more than 4GB), and SATA drives work fine in a bay.


It would be vast overkill. The TiVo isn't some silly Windows or other GUI based user platform. As I mentioned in the previous post, the total of all the OS partitions is substantially less than 1G, and most of that isn't used:

```
bash-2.02# df -h
Filesystem            Size  Used  Avail  Capacity Mounted on
/dev/hda4             248M  105M   130M     45%   /
/dev/hda9             248M   27M   208M     11%   /var
```
Although there is no good reason to do so, by using compressed images, it could all fit on a single 256M flash drive, including both the active and inactive partition sets.



classicsat said:


> The PROM chip would try to boot the drive, and if it fails it would boot the Flash drive, which would run further tests to see if it is an empty drive, or what has failed and needs installed. The Flash drive would hold its boot/kernel/root (OS/application), and images for the factory OS version, the last two OSes (boot/kernel/root), and the root Database.


Well, that's a possibility, although I would not expect them to take that path. I would expect them to simply boot from the solid state drive in the first place.


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