Why can I unplug my DVR when its running?

[techs]

Quite often I have to unplug my Comcast DVR when it locks up. Yet, if I unplug my computer when its running I damage the hard drive.

Are hard drives in DVRs designed to withstand loss of power? Are there capacitors on the drive to power it down gently?

 

[TerryMathews]

Quite often I have to unplug my Comcast DVR when it locks up. Yet, if I unplug my computer when its running I damage the hard drive.

Are hard drives in DVRs designed to withstand loss of power? Are there capacitors on the drive to power it down gently?

How do you damage your computer's hard drive? Are you meaning the Windows check disk thing?

To answer your question, the drives have a clutch that should keep the head from hitting the platter in the case of a power failure. It won't prevent data damage, it will prevent physical damage.

It doesn't hurt your DVR because it just puts a hole in the recording and it uses a file system that handles power failures gracefully, probably a journaled FS like Reiser or EXT3/4

 

[Schmide]

You don't damage the hard drive???!!!, you prevent writes from finishing. When you boot next both the computer and the DVR have to check the disk for lost fragments (open files) and clean them up.

 

[Lean L]

It's funny that people thing you damage hard drives by pulling the power.

 

[cronos]

It's funny that people thing you damage hard drives by pulling the power.

I guess because back in the days we had to manually type 'park' before we turn off our computers or we risk losing data.

 

[disappoint]

Why can I unplug my DVR when its running?

Because you have opposable thumbs.

 

[sciencewhiz]

It doesn't hurt your DVR because it just puts a hole in the recording and it uses a file system that handles power failures gracefully, probably a journaled FS like Reiser or EXT3/4

Tivo created a file system specifically to handle streaming and be fault tolerant. http://en.wikipedia.org/wiki/Tivo's_Media_File_System

 

[Possessed Freak]

I guess because back in the days we had to manually type 'park' before we turn off our computers or we risk losing data.

Yeah if you were using MFM/RLL drives.

 

[AustinInDallas]

i dont think thats been a thing for a long time

 

[Scarpozzi]

Most hard drives have quite a few extra sectors to repurpose in the event of damaged sectors...

As stated a journaling filesystem will fix any data loss...the physical drive probably won't see any damage unless there is a power spike that's not stopped by a surge protector or capacitors in the internal DVR power supply.

 

[TerryMathews]

Tivo created a file system specifically to handle streaming and be fault tolerant. http://en.wikipedia.org/wiki/Tivo's_Media_File_System

Yes they did, however it's patent encumbered. I assure you Comcast isn't using it.

 

[SunnyD]

Because of OS design and legacy issues.

Money says that your DVR uses an embedded OS and only uses the drive for storage. You have no way to fuck up the OS with unwritten data/open handles/etc if it powers off, because it's stored in non-volatile memory in a read-only state.