# The Tools We Use



## Marconi (Sep 8, 2001)

I'm curious about the inner workings of the tools we use to upgrade/expand our TiVos' capacities. Before I get started though, a bit about myself: In a former life, I was system admin for some 30 Sun SPARCstation 5s so I still have a bit of residual Unix knowledge. I've been a Mac user since the beginning (1984) and was an Apple ][ user before that. I never really got into DOS and my Windows exposure was a job requirement. 

My Mac knowledge is vast but I do have some Windows boxes (an old 98 SE box and one not quite as old XP box) that I've kept around for the occasional need and, in the case of the 98 SE box, for doing my TiVo upgrades. Then I found out that an Intel Mac will boot and run MFSlive and have been using that exclusively for swapping new drives into my TiVos. I use multiple USB adapters to connect the various drives and MFSlive 1.3b to do the work. 

As I write this, I'm waiting for FedEx to deliver a pair of 750 GB drives for the bedroom TiVo, to replace its pair of 120 GB drives. I had intended to swap out the two drives in it for a single 1 TB drive but found that I cannot do that with the current tools, and retain recordings. This got me to wondering about the tools and how they work, and about the community's collective knowledge about the inner workings of this thing we call TiVo. 

Each expansion adds partition(s) to the drive(s) and there's a limit on the number of partitions. The partition limit: is that an OS restriction? 

The current tools cannot go from two Drives to one drive while retaining recordings. Do the tools recognize recordings or only recordings partitions? That is, if I tell the tool to copy recordings, does it locate and copy the recordings one by one or does it simply copy the partition(s) where recordings are known to be stored? Related question: All other things being equal, if I delete half of the recordings from a TiVo, will it make the copying of the old drives any faster or will it copy the entire recording partition(s) regardless of whether there are actual recordings there? 

From reading the forums, I see that I am not alone in wanting to go from two drives to one, while retaining recordings. I'm guessing that this cannot be done because the tools just copy partitions, and one cannot copy two drives' worth of partitions onto one new drive. (Anyone care to confirm this?) 

My plan had been to back up to a file, then restore the file to a new, larger single drive. This, I was told, cannot work if I have many recordings at all, because of the current 4GB maximum file size limit. The current tools back up to Windows FAT32 volumes or some such, yes? And the 4GB limit is a FAT32 limit?

Suppose we use a file system (for the backup) that does not have that limit? Would the process of backing up everything from two drives to a file, then restoring the file to a single drive work?

Or does backing up to a file simply copy partitions to a file -- partitions that have to be restored to an equal number of partitions on the new (restore) drive? 

Current Mac OS is limited in file size only by the size of the volume itself. If I used a Mac volume (HFS+) as the backup, would, theoretically, the two-drives-to-a-file back up followed by restoring the file to a single drive work, while retaining recordings? If the file size limit is the only thing preventing the preserving of recordings while going from two drives to one, then use of a HFS volume would seem to be a solution. One wouldn't even need a Mac, just a HFS formatted volume to hold the back-up file. 

Do current tools recognize Mac HFS volumes? (Mac OS X recognizes TiVo volumes/drives, though it does not automatically mount them.) 

In MFSlive, I've tried: mount -t hfs /dev/sdb2 /hfs
with no luck, so I'm guessing that "hfs" is not an internally recognized file system type. Is there some designation other than "hfs" to use for the volume? 

If MFSlive does not recognize hfs, is there a way to add it? I found, via Google, how to add support for hfs to Unbuntu. Anyone know if it's possible to add it to the MFSlive ISO?

Anyway, I've been trying to better understand the tools I've been using. Any and all comments / answers / insights will be appreciated.


----------



## Southcross (Nov 28, 2008)

way over thinking this....

follow the instructions from here:
http://www.mfslive.org/fullguide.htm

...and yes, you can combine a two-drive Tivo onto one single larger HD:
http://www.mfslive.org/softwareguidep3.htm


----------



## Marconi (Sep 8, 2001)

Southcross said:


> way over thinking this....


No, just gave it more thought than you have.



Southcross said:


> follow the instructions from here:
> http://www.mfslive.org/fullguide.htm


Nope. This helps me not at all. I've read this extensively, have you?



Southcross said:


> ...and yes, you can combine a two-drive Tivo onto one single larger HD:
> http://www.mfslive.org/softwareguidep3.htm


If you actually read what's there, you understand that it only works if you have FEW recordings. This is why I stated that the process is limited by the 4GB max file size of FAT32.

Really, I did research this before putting a lot of thought into it and posting my questions -- none of which you have answered.


----------



## mattack (Apr 9, 2001)

Umm, no, it's not FAT32. Someone else (not anybody at Tivo) told me it's a slightly modified HFS, but I have no firsthand knowledge of that. (If that's true, I would love to be able to hook my drive up to a Mac and get recordings off directly that way!)


----------



## Marconi (Sep 8, 2001)

mattack said:


> Umm, no, it's not FAT32. Someone else (not anybody at Tivo) told me it's a slightly modified HFS, but I have no firsthand knowledge of that. (If that's true, I would love to be able to hook my drive up to a Mac and get recordings off directly that way!)


What's not FAT32? My reference was to the volume typically used for a backup file and mounted on /dos. What are you saying is a slightly modified HFS?


----------



## mr.unnatural (Feb 2, 2006)

The Tivo partitions are not FAT32. FAT32 partitions are only required if you are using your Windows partition for mounting purposes to create backup images, restore images, or otherwise transfer files to and from the Tivo partitions. FAT32 is required for this because the Linux distributions used with the MFSTools boot discs will not recognize an NTFS partition. WinMFS is the only Tivo utility that will work with both Tivo partitions and NTFS.


----------



## Marconi (Sep 8, 2001)

mr.unnatural said:


> The Tivo partitions are not FAT32.


I hope this "correction" is not intended for me, as I never said they were. 


mr.unnatural said:


> FAT32 partitions are only required if you are using your Windows partition for mounting purposes to create backup images, restore images, or otherwise transfer files to and from the Tivo partitions.


That is exactly the point I made. And the FAT32 volumes have a limit of 4 GB max file size. This is why I suggested trying to use a Mac HFS volume as the backup volume.


mr.unnatural said:


> FAT32 is required for this because the Linux distributions used with the MFSTools boot discs will not recognize an NTFS partition.


Thus my question: Will mfstools and the like recognize a Mac HFS partition? If so, the 4GB file size limit can be avoided and it will be possible to back up two drives to a file and then restore to a single, larger drive. (A lot of people want to do this.) This is not possible using FAT32, if you have even a few recordings you want to preserve.


----------



## classicsat (Feb 18, 2004)

Marconi said:


> Each expansion adds partition(s) to the drive(s) and there's a limit on the number of partitions. The partition limit: is that an OS restriction?


It is the limit of the TiVo partition system. It supports only 16 partitions. When a TiVo is made, it has only three free, and an expansion takes two.



> The current tools cannot go from two Drives to one drive while retaining recordings.


It can if either drive is unexpanded, and by copying the A drive and the two media/MFS partitions from the B drive to the new A drive, which will be large enough for all of them. Mfstools will adjust the directory to know of the change.
Of course, the TiVo will have the same capacity as before, just with one drive instead of two.



> Do the tools recognize recordings or only recordings partitions? That is, if I tell the tool to copy recordings, does it locate and copy the recordings one by one or does it simply copy the partition(s) where recordings are known to be stored?


It only copies partitions. If you tell it to copy no recordings (the -s option in the copy), it will make empty media partitions.


> Related question: All other things being equal, if I delete half of the recordings from a TiVo, will it make the copying of the old drives any faster or will it copy the entire recording partition(s) regardless of whether there are actual recordings there?


I believe it may copy bit for bit, recording or not.
I could be wrong.


> My plan had been to back up to a file, then restore the file to a new, larger single drive. This, I was told, cannot work if I have many recordings at all, because of the current 4GB maximum file size limit. The current tools back up to Windows FAT32 volumes or some such, yes? And the 4GB limit is a FAT32 limit?


The backup file will still have the partitions of the system it was copied from.

4GB is the limit of FAT32, but it is artificial, because most people use Windows machines and want dual compatiblility, so FAT32 is often used.

Practically MFStools could back up to any drive with a partition that its Linux OS can write large files to. I think EXT3 can do.



> Or does backing up to a file simply copy partitions to a file -- partitions that have to be restored to an equal number of partitions on the new (restore) drive?


That is what it does.



> If MFSlive does not recognize hfs, is there a way to add it? I found, via Google, how to add support for hfs to Unbuntu. Anyone know if it's possible to add it to the MFSlive ISO?


The better was would be to add the bits to Ubuntu to work with TiVo partitions, mfstools, as well as HFS+, if you can.


----------



## ciper (Nov 4, 2004)

This thread covers many of the restrictions when upgrading drives (especially page 2)
http://tivocommunity.com/tivo-vb/showthread.php?t=416133


----------



## Marconi (Sep 8, 2001)

classicsat said:


> It is the limit of the TiVo partition system. It supports only 16 partitions. When a TiVo is made, it has only three free, and an expansion takes two.


Leaving only one free partition? Inasmuch as an expansion adds partitions in pairs, that would mean only one expansion is possible. This is at odds with what I read elsewhere:

"The next limit is in the partition table. It has a maximum of 16 partitions per drive
Then the MFS can only have 12 partitions, the TiVo comes with 4 already and they are added in pairs so usually you can only upgrade a maximum of 4 times. 4times * 2partitions = 8 + 4stock = 12 total"

Given the partition limit, is there no way to expand individual partitions? Can't the same number of (larger) partitions be written to an upgrade drive by the backup | restore process? Have any of the tool developers tried this?

Regarding the partition limit: What happens when one tries to increase capacity via a backup | restore when either of the drives is already at the limit? Example: Drive A is 200 GB and 15-16 partitions, Drive B is 200 GB and four partitions. The replacement drives are 500 GB each. When the backup | restore is attempted, will it exit with an error? Will the expansion succeed but use only 200 GB of the new A drive (but all 500 of the new B drive)? Or will it go through the motions and, to all appearances succeed, only to not work in the TiVo? (Failure to boot or crash, etc.) Just curious.


----------

