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Hate your HD-DVR? I apologize to all of you...

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by jfalkingham, Mar 26, 2009.

  1. harsh

    harsh Beware the Attack Basset

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    Understand that the DVRs don't use off-the-shelf SIMMs -- they use surface mount chips. The economies of scale are not the same.
     
  2. BattleScott

    BattleScott Hall Of Fame

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    First problem is that a different processor would very likely not have the same pin layout as the current one so a swap out would not be a possibility. Furthermore, the code for these boxes is written specifically for the chipset used.
    Assuming you could find a "faster" version of the same processor that was a pin for pin match and would work with the existing code, these devices are BGA (Ball Grid Array) from factor so they require some extremely expensive rework equipment to remove and replace that most repair shops can't afford. In devices designed to be "upgraded" these types of chips are usually installed on a seperate module that plugs into the device, on disposable consumer devices like these they are usually installed directly to the main pcb to save manufacturing costs.

    It's very doubtful that the memory is dynamically allocated in these devices. So even if you could add memory, there likely wouldn't be any perfromance benefit to it.
     
  3. Steve

    Steve Well-Known Member

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    :) Was with you up to here:
    Are you saying these boxes don't rely on the OS to manage memory (and therefore virtual memory) use? Because assuming they do, then adding more RAM should certainly cut down on disk-swapping, which has to help.

    E.g., while I have no direct knowledge of this, I always imagined that the need for "tuning" we often talk about is addressed by playing with the Unix "nicing" values for the various resident processes, and is not directly related to how memory is used, which is managed by the OS. That said, I never managed development of an application such as this, so I could be totally off-base. /steve
     
  4. BattleScott

    BattleScott Hall Of Fame

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    I'm not saying that performance couldn't be increased with more memory AND the code tweeking that you mention. Just that simply adding more memory wouldn't acheive anything. In other words, I don't believe that the code is designed to support dynamic memory allocation, meaning that whether or not a function utilizes a disk-swap transaction would not change simply because more memory was added. It would require the code to be changed to allow decisons about how functions are handled based on available memory.
    Typically, these types of devices are coded around a specific memory structure and are designed to operate within that environment. I don't believe the OS is used for anything more than the basic runtime kernel to provide access to the hardware level resources by the main code, and is not "actively" managing the system resources like we think of in a traditional computer system.
    Of course, this is based strictly on my experience with other purpose built appliance computers, not any direct experience with these particular ones so I could be off in that regard, but the rest is still valid as to the viability of a processor swap...:)
     
  5. harsh

    harsh Beware the Attack Basset

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    As everything is surface mounted that lets out most hardware upgrades. It might be possible to do some sort of fly-wire socket installation but it would be extremely expensive and not entirely immune from various and sundry interference issues.

    One of the advantages of having a single platform is that you can make some pretty sweeping assumptions about what is or isn't available and how much.

    The best way to eke out all possible performance is to not implement a bunch of cool technologies like virtual memory. Using hardwired addresses is usually more efficient than using vectors and pointers. Bank switching is not your friend in a multi-tasking scenario.

    These chips are not general purpose devices and were not meant to be a sledge hammer as was common in computers before GPUs.
     
  6. Rich

    Rich DBSTalk Club DBSTalk Club

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    Damn. That "First Look at the 23s" led me to believe that the 23 was gonna be an upgrade on the other HRs. What happened there?

    Rich
     
  7. harsh

    harsh Beware the Attack Basset

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    Most who have seen them in operation have testified that the picture quality is noticeably better.
     
  8. Rich

    Rich DBSTalk Club DBSTalk Club

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    I had so much trouble with TiVos and they were all hard drive related. The HRs don't seem to have that problem. I know that the big difference is where the OS resides and I hope that the TiVos don't just overpower the HRs when they come out.

    Rich
     
  9. Rich

    Rich DBSTalk Club DBSTalk Club

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    That was interesting. I could read the words, but I have no idea what your conclusion means. But, the argument brings up a question that has bothered me for years, so many devices can be either internal or external, why not a device that would hold memory chips and could be connected via USB or Firewire or whatever is left?

    Rich
     
  10. Steve

    Steve Well-Known Member

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    IIRC, there was some subjective opinion that audio was superior on the HR23, but I don't have one so can't comment on what differences, if any, folks were hearing.

    Since the HR23 is just acting as a DD 5.1 pass through device, I'm not sure how the sound could be any different, except perhaps for output volume. /steve
     
  11. Rich

    Rich DBSTalk Club DBSTalk Club

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    That's the only plus I've seen and that is pretty subjective. Lots of adverse posts about them. Be interesting to see for myself. I really wanted to believe that "First Look".

    Rich
     
  12. harsh

    harsh Beware the Attack Basset

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    Two words: bus speed.

    Performance in computers is directly related to how quickly things can communicate between one another. That's why cache RAM makes such a big difference. Hanging RAM out on a USB bus would be like connecting to your hard drive via a dial-up modem.
     
  13. Steve

    Steve Well-Known Member

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    Again, the HR23 uses the same decoder as the HR21/22, so I don't understand how there can be a visual difference between models decoding and passing the same satellite bits read from disk to your display device. Not logical to me. /steve
     
  14. harsh

    harsh Beware the Attack Basset

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    A surprising number of comments to the contrary came from those who had/have never auditioned an HR23.

    The main downside that I can think of is possible diplexing complications.

    The HR23 is, after all, just another DIRECTV Plus HD DVR.
     
  15. harsh

    harsh Beware the Attack Basset

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    To be certain, it defies logic, but logic doesn't always apply where contouring is present.

    Maybe they adjusted some output section and the picture and/or sound is "brighter" which may seem "better" (this was an old computer sound card trick; remove the hiss filtering and bingo, it sounds like it has improved top-end response).
     
  16. Rich

    Rich DBSTalk Club DBSTalk Club

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    The audio portion doesn't really interest me. I'm satisfied with the audio on the HRs and I was satisfied with the audio on the old SD TiVos. After firing 5" guns for years and banging out solidified resin from iron pans with a sledge hammer, my hearing (which was good enough to qualify me for being a Sonar Man) is shot at both ends of the sound spectrum. Put simply, music holds little interest for me. Used to enjoy it, but I can tell something is missing.

    Hear (no pun intended :lol:) anything else good about them? I was pretty close to ordering one yesterday, then I started thinking about all the negative posts I've read. I wonder if there is such a thing as "prebuyers remorse"?

    Rich
     
  17. Rich

    Rich DBSTalk Club DBSTalk Club

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    Good explanation. Seemed like a good idea...

    Rich
     
  18. BattleScott

    BattleScott Hall Of Fame

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    Basically I'm just saying that aside from what I say about how the software functions, the hardware restrictions alone are enough to prohibit a processor upgrade like the poster was asking about.
    As for plugging additional memory in the USB slot, that would be less efficient than using the SATA bus and hard disk as USB2.0 is a much slower interface.
     
  19. Rich

    Rich DBSTalk Club DBSTalk Club

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    I've read some posts that said the PQ was better, but I still think that's an awfully subjective subject. What I focused on in the "First Look" was what seemed like faster processing speed and improved PQ. If the PQ was that much better, wouldn't we expect to see a lot of posts raving about the PQ?

    Rich
     
  20. Rich

    Rich DBSTalk Club DBSTalk Club

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    Naive, I must be. Never occurred to me that someone would post anything about something they've never used.

    Diplexing in the context of OTA?

    Yeah, but it is made by Pace and the best HRs I've had have been 700s. I don't really have a use for another HR and I'm willing to wait until Costco gets them, so I do have time for more research and consideration of whether I really want another HR (can you really have too many HRs?).

    Rich
     

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