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For those of you that "want to know"..

Discussion in 'DIRECTV SD DVR/Receiver Discussion' started by Wolffpack, Mar 7, 2006.

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  1. Mar 7, 2006 #1 of 160
    Wolffpack

    Wolffpack Banned User

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    Ok, As some of you may know, I've been doing some digging into the R15 just cuz I want to know. For those of you that are as curious as I am as to how things "might" work, the following is what I may or may not have found. :rolleyes:

    • It has been reported here and referenced over at DealDatabase.com that another user had performed a Unix "dd" copy of a drive from an R15 to a blank drive, inserted it into the R15 and it booted and ran without any noticed problems. I have tried the same and can verify this. I did not run into any problems with a new copy of the original drive in the R15. Maybe at least a backup method for those that don’t want to loose their MYVOD. Keep in mind this does involved pulling the drive from your R15, placing it in a PC, booting a version of Linux and performing a dd copy.
    • I have been looking at the filesystem utilized by the R15 and it is tagged as a FAT32 partition. Mounting that partition on a Linux system works and one can browse through the drive seeing all files and directories. Appears to at least be FAT32 compatible.
    The "files" under the root directory of the drive are few and most are coded as "system" files. They are as follows:​
    Code:
    -rwxr-xr-x   1 root     root      3130196 Mar 24  2034 jopa*
    -rwxr-xr-x   1 root     root         1816 Feb 17 18:47 pcredit.dbf*
    -rwxr-xr-x   1 root     root         4976 Mar 24  2034 pman.dbf*
    -rwxr-xr-x   1 root     root       239202 Feb 17 16:25 signup.dbf*
    -rwxr-xr-x   1 root     root        16104 Mar 24  2034 supp.dbf*
    -rwxr-xr-x   1 root     root        52292 Mar 24  2034 xcatgry.dbf*
    -rwxr-xr-x   1 root     root         4346 Mar 24  2034 xclient.dbf*
    -rwxr-xr-x   1 root     root          532 Feb 18 15:51 xsetup.dbf*
    • As shows are recorded a set of files, associated with each show are stored in a directory under the root directory. So each show that you may have in your MYVOD equates to a directory under the root directory. This concerned me as to the known limitations with a FAT32 filesystems. The files within this directory are all named the same and the directory name is meaningless. For example:
    Code:
    12:
    total 747776
    -rwxr-xr-x   1 root     root         8928 Feb 18 00:00 meta_man.xm\001*
    -rwxr-xr-x   1 root     root          705 Feb 18 00:00 meta_man.xmd*
    -rwxr-xr-x   1 root     root        20170 Feb 18 00:00 meta_man.xmi*
    -rwxr-xr-x   1 root     root        11993 Feb 18 00:00 meta_man.xmv*
    -rwxr-xr-x   1 root     root            0 Feb 18 00:00 stream.ext*
    -rwxr-xr-x   1 root     root     765591552 Feb 18 00:00 stream.str*
    In this example the directory name is 12. As in c:12. From the file sizes the “stream.str*” would seem to contain the video stream.​
    • On the backup drive I created I tried the DOWN ARROW/RECORD method. The R15 did come back quickly with a drive minus all shows and SLs.
    I'm working further on the filesystem as there can be no way DTV would have used a FAT32 filesystem for this product. I have some clues it may be more a FAT64 file system with compatibility backward to FAT32. Allowing file sizes > 4GB and partition sizes up to 2TB. Very interesting stuff.

    But this is all just me being curious. If any of you are also curious, jump in. I would love to hear your observations.
     
  2. Mar 7, 2006 #2 of 160
    Blurayfan

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    Thanks for the details. Maybe someone could now locate a way of increasing the partition size on the new drive giving the true upgrade we all are wanting.
     
  3. Mar 7, 2006 #3 of 160
    Earl Bonovich

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    [jar jar]Me's just think you's gots to much time on your hands.... [/jar jar]

    Just kidding...

    It is intresting to see that.. I wish I had more time to tinker with it.

    Did you or the DDB user, try DDing to a larger drive, and if so... did it take the new space into consideration?
     
  4. Mar 7, 2006 #4 of 160
    Wolffpack

    Wolffpack Banned User

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    Using a "dd" copy is a bit by bit copy. In my test I copied the 160GB drive to a 250GB. But that was seen as a 160GB partition on a 250 GB drive. I did try the DOWN ARROW/REC operation however that left the 160GB partition as is.

    To expand the partition size correctly one needs to alter the filesystem. I'm still working on that. FAT64 is the key. I may have even stumbled upon the vendor of the filesystem but I'm still working on that also.

    Hey, for $25,000 I'll spend a little time on it.

    Oh, BTW, not sure if anyone noticed but the Volume name on the drive is XTV_STR_DSK. Gee, wonder where that came from.
     
  5. Mar 7, 2006 #5 of 160
    Clint Lamor

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    Would be interesting if you could move it to a larger driver and also are you able to look at the FAT table itself to see what it says about the drive?
     
  6. Mar 7, 2006 #6 of 160
    Wolffpack

    Wolffpack Banned User

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    It's not a "legal" FAT32 filesystem as it shows 99% of the drive space being used. The two FATs do not show the same. It's most definetely an expanded FAT32, which at this point I'm calling FAT64. If I figure out any more, I'll post it.
     
  7. Mar 7, 2006 #7 of 160
    Wolffpack

    Wolffpack Banned User

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    Oh, as an addon, has anyone pulled the cover on the R15 to know why it's so much more quite than the DTivos?
     
  8. Mar 7, 2006 #8 of 160
    walters

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    http://www.ebsembeddedsoftware.com/spotlight.htm

    Of course, I'm really interested how they managed full backward compatibilty with FAT32 while at the same time breaking the 4GB barrier. :confused:
     
  9. Mar 7, 2006 #9 of 160
    Earl Bonovich

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    When I pulled teh cover when I did the original review....

    There was nothing "speciall" about what was going on in there (As in a building perspective)

    My guess... the R15 is using the drive in a mannet that isn't causing the heads to go flying around (aka the noise we hear from a very active DTivo)
     
  10. Mar 7, 2006 #10 of 160
    thumperr

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    This may sound dumb, cause it does not make full sense to me.

    But why is the 4GB file size limit an issue. wouldn't the system just use pointers to link to the next file? Link chapters on a DVD. I can't remember the filesystem for the UTV, i think it was FAT32. but you can record for hours with it, i'd guess they used some type of pointer scenario to make this work.

    The other features mentioned in the link for FAT64 would be nice.

    I believe with the UTVs, that they used some new security feature in the hard drives at the time they came out. this was why some drives worked for the upgrade and some did not. as i recall you had to use WD drives at first. Maxtors would not work. It is possible that there is new drive feature that D* is using with this.

    Would have been nice if D* had used the UTV approach. let the user swap the drive(simple task) and have it phone home and update. This way no need for someone to try and hack it for the upgrade. keeps people from poking around. this may not have been compatible with their lease plan.
     
  11. Mar 7, 2006 #11 of 160
    Wolffpack

    Wolffpack Banned User

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    Did you notice the rubber grommets on the drive mount? Almost every name brand PC case manufacturer that includes drive cages now include the rubber grommets. Amazing how quite a system is once the vibration from the HDD to the chassis is reduced via a tiny piece of rubber.

    Kudos to DTV for taking this approach.

    Well, plus they stopped using WD drives and went with Seagates.
     
  12. Mar 7, 2006 #12 of 160
    Wolffpack

    Wolffpack Banned User

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    Linking multiple files would work, but seeing that they have exceeded the 4GB limit is encouraging as they are not using a stock FAT32 filesystem.

    If they're using the one I think they are, it also include journaling, which must be required for an application such as this if it is ever to work.
     
  13. Mar 8, 2006 #13 of 160
    ScottJ

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    So, a subfolder for each program in VOD?

    That might explain why problems seem to increase as data on the machines increases.

    FAT32 in a high I/O environment with many subfolders can be flakey IME.
     
  14. Mar 8, 2006 #14 of 160
    walters

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    Are you thinking of the one I linked above, or did you find another one?
     
  15. Mar 8, 2006 #15 of 160
    cabanaboy1977

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    What does DOWN ARROW/RECORD method mean?

    Wolffpack, I forgot do you only have one R15? I'm still wondering if you can swap HD between two R15's. That way you wouldn't lose shows/SL if you R15 died due to a non-HD issue. I hope you can. That was my biggest issue with the UTV's the tuner would die or the power supply and you lost all your shows and SL.
     
  16. Mar 8, 2006 #16 of 160
    Earl Bonovich

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    DOWN ARROW/RECORD

    Is the non GUI method to initiate a "Clear and Delete"

    And to Cabanaboy....
    I have two... and once I can get my hands on a 160 or larger drive, I will give it a shot....
     
  17. Mar 8, 2006 #17 of 160
    Bobman

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    All this sounds nice but what does it really tell us non technical laymen ?
     
  18. Mar 8, 2006 #18 of 160
    Wolffpack

    Wolffpack Banned User

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    Yep.
     
  19. Mar 8, 2006 #19 of 160
    Wolffpack

    Wolffpack Banned User

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    Not much. :D It really doesn't mean much for technocal folks either. Just in case anyone was interested.
     
  20. Mar 8, 2006 #20 of 160
    cabanaboy1977

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    Ok, I know what he's talking about now. I thought a linux command.

    I would have tried it with my 3 but i'm afraid that it's going to marry with the drive like the UTV did and then I'll lose all the recordings. I don't want to lose my recordings. I wish I had thought about it before I started filling them up with SL. BTW if you want a cheap Samsung 160GB or 200GB drive, the mircocenter on odgen in westmont has them for ~$79-99.
     
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