# please add drive error correction to all boxes



## ejonesss (Aug 13, 2007)

it would be nice if tivo could add error correction to all boxes especially starting with series 4.

make the error correction like it is on a pc.

while recording if a bad sector is detected then it locks out that sector and re writes the data to another sector.

and do this on the fly using something like crc checksum.

tivo you may say this cant be done retroactively.

helloooowwww!!!!! yes it can be done retroactively it can be done in software.

the data is written to the drive then verified and rewritten if bad sector is detected and sector is locked out.


----------



## HomeUser (Jan 12, 2003)

No need, All modern hard drives expect bad sectors and relocate problem sectors from a block of spares automatically with the next write. When the OS knows about it all the spares have been used and the drive is pending failure and should be replaced. See SMART parameter "pending sector count".


----------



## ejonesss (Aug 13, 2007)

the drive in the box is not smart compliant otherwise it would have shown smart compliant in disk utility.

the drive was pulled from a retail wd my book 2tb external.

also just like trim smart i think has to be enabled by the os.

my suggestion would be where the os would do it and would prevent the video from ever being recorded to a bad sector/block.

my problem is when i download the videos via the ttg feature they will get to the high 90's % and will stop and hang there and eventually the downloader will see "ok the file is done" and stop the download.

then when i start the next download it hangs waiting for tivo.

the only way out is to restart the tivo either by the menu or to power cycle it unplug it and plug it back in.

now if the tivo software would do the error detection then i would have smooth downloads every time.

next you may say "ok the file is being corrupted by unexpected aborts caused by the emergency broadcast system"

wrong unlike cable co boxes tivo boxes *DO NOT* respond to the emergency broadcast system commands so they act like a vcr and record everything (catch all)

i have seen an emergency broadcast system amber alert show one in the middle of a recording so you cant tell me it is corrupt by the emergency broadcast system.


----------



## HomeUser (Jan 12, 2003)

ejonesss said:


> the drive in the box is not smart compliant otherwise it would have shown smart compliant in disk utility.
> 
> the drive was pulled from a retail wd my book 2tb external.
> 
> also just like trim smart i think has to be enabled by the os.


 What 2TB drive do you have that does not have SMART? IAC it will have auto correction. Some software hardware combinations make it difficult to access the logs especially if you are using a SATA to IDE adapter. Media drives use a lower number of re-reads before giving up on the data.



> my suggestion would be where the os would do it and would prevent the video from ever being recorded to a bad sector/block.


 Would be nice, how is the OS going to know the sector is bad before writing / verifying the data? Marking a sector as bad by the OS is old school that function has been replace by the drives firmware when the OS knows about the failure the failure rate has become so high the drive has passed it's useful life And the MFS file system does mark blocks as bad automatically.



> my problem is when i download the videos via the ttg feature they will get to the high 90's % and will stop and hang there and eventually the downloader will see "ok the file is done" and stop the download.


 I don't think that is a hard drive issue rather a network issue. There are several discussions here about that. I have seen that problem several times replacing a network switch cured it for me. Other causes were reportedly caused by AV software that throttles the transfer speed for programs that send large amounts of data thinking the program may have a problem. And Yes! I think TiVo needs to handle network failures better. The next time instead of rebooting the DVR try changing the network settings to something else force a connection (error) then back to see if the change will free up the locked network / buffer without rebooting. I was going to try that next time except the switch had fixed the problem.



> unlike cable co boxes tivo boxes DO NOT respond to the emergency broadcast system commands so they act like a vcr and record everything (catch all)


 Which TiVo do you have? any that use the Cable Card the DVR is requited to respond to EAS messages unless the DVR is not actively being watched. That is a major reason to put the DVR into stand by when not watching it.


----------



## ejonesss (Aug 13, 2007)

if the os could read the drive's specs (can be done since there are technical programs that can give reports on all hardware) and can see the sector size then it can break the video up into sector sized chunks.

then write the chunk and time how long it takes to write and generates a crc for that chunk.

then reads that chunk back and generates a crc on that chunk then compares the crc.

if there is a mismatch in the crc then mark in the drive's toc that sector is bad and then write that chunk to the next sector and repeat .

cant be network issues since the box can still be logged into.

i have the series 4 746 version and it still displays the emergency broadcast service messages but it does not stop the recording to display them so the content will have the message.

cable co boxes stop the recording and resumes the recording.


----------



## Scooby Doo (Dec 18, 2002)

What exactly do you think this is going to accomplish? Better video quality? I doubt there would be any observable difference. The bit error rates on hard drives are extremely low and so introduce very little noise into the signal; certainly way less noise than is already introduced by compression and transmission. PCs are very different because even very low bit error rates are unacceptable for apps.


----------



## HomeUser (Jan 12, 2003)

Because of the transfer overhead the write/read verification is much more efficient to do in the hard drive's controller, close to what modern drives do now. Media drives turn the threshold down or off for speed. A few lost pixels is less noticeable then freezing video due to data starvation.

I am not sure if the timing of the writes would be possible by the high level software the drives buffers would mask it. I think that was the original idea behind S.M.A.R.T to make monitoring the drives condition easy. Because different manufactures report the data differently it is not easy to interrupt by the OS. Most computers that I deal with only check the S.M.A.R.T values for error during boot-up.



ejonesss said:


> cant be network issues since the box can still be logged into.


True it probably is not a networking error because it is always stop around 90% that would be more like a corrupt file, transfer being blocked by a firewall quota or a file size limit. What size is the program you are transferring? If your PC is formatted FAT32 there is a ~4GB file size limit. "You cannot create a file larger than (2^32)-1 bytes (this is one byte less than 4 GB) on a FAT32 partition."

Still TiVo really needs *TO FIX* a failed transfer locking all other transfers. Did you have any luck trying to recover MRV by changing the network settings instead of re-boot?



ejonesss said:


> i have the series 4 746 version and it still displays the emergency broadcast service messages but it does not stop the recording to display them so the content will have the message.
> 
> cable co boxes stop the recording and resumes the recording.


I don't recall seeing a EAS message since having the Series 4. If one is available The S3 uses a free tuner to display the EAS message and keep recording on the other(s).


----------

