SD Card Extension

[Crimson Nape]

Since CPAPs don't have a soft disconnect (screen prompt), I would hazard a guess that when you press the On/Off switch, it signals a final write to the SD.

[Galactus]

Newbee2016,
This applies even if you’re not actually using the device at the time.

The reason is because operating systems use a process called write caching. The operating system doesn’t always write a file to a drive immediately, but instead caches it and waits until it has multiple write operations to complete.

Doing these all at once improves performance, but if the cache is still full when you remove the drive, your data will become corrupted. Clicking the Eject button causes the cache to be emptied and any remaining data to be written to the drive.

That’s the reason why there’s often a delay of several seconds between ejecting the drive and being notified that it’s safe to remove it.

There are also potential issues with the abrupt removal of the power supply from a flash drive. Flash memory is susceptible to this, and it can cause parts of the drive to become corrupt.

I hope this may help.

ok!

Now I wonder if the PR machine uses this method of write caching as well, or writes the data progressively as it is generated while in use. 

For a safe bet, if, say I've woken up for the morning, and switched the machine off at the wall for the day, I'm sure any writing would have ceased and it ought to be safe to remove the SD Card from the extension slot. Thereafter do what I will with the SD Card and re-insert it back into the extension slot in readiness for the night's usage, when I would turn the power on again. 

As it is, I would on/off the machine everyday. Just that I would move the SD Card to / from the machine when the machine is still on. I could change this part and move the SD Card to/ from the extension when the power supply is off - as added precaution against damaging the SD Card. 

Depending on the OS you are using you should be able to tell the card not to cache data on the PC, that will avoid corrupting the card with an unsafe removal. I've had to do this with USB drives and sticks in the past as well.

My PRS1 760 has a screen that flashes something like "Do not remove card writing data" when you tuen it on, I never really looked after I woke up as it's on the bedside, and by the time i get the P10 off I presume it's done.

Hope that helps.

[Newbee2016]

Newbee2016,
This applies even if you’re not actually using the device at the time.

The reason is because operating systems use a process called write caching. The operating system doesn’t always write a file to a drive immediately, but instead caches it and waits until it has multiple write operations to complete.

Doing these all at once improves performance, but if the cache is still full when you remove the drive, your data will become corrupted. Clicking the Eject button causes the cache to be emptied and any remaining data to be written to the drive.

That’s the reason why there’s often a delay of several seconds between ejecting the drive and being notified that it’s safe to remove it.

There are also potential issues with the abrupt removal of the power supply from a flash drive. Flash memory is susceptible to this, and it can cause parts of the drive to become corrupt.

I hope this may help.

ok!

Now I wonder if the PR machine uses this method of write caching as well, or writes the data progressively as it is generated while in use. 

For a safe bet, if, say I've woken up for the morning, and switched the machine off at the wall for the day, I'm sure any writing would have ceased and it ought to be safe to remove the SD Card from the extension slot. Thereafter do what I will with the SD Card and re-insert it back into the extension slot in readiness for the night's usage, when I would turn the power on again. 

As it is, I would on/off the machine everyday. Just that I would move the SD Card to / from the machine when the machine is still on. I could change this part and move the SD Card to/ from the extension when the power supply is off - as added precaution against damaging the SD Card. 

Depending on the OS you are using you should be able to tell the card not to cache data on the PC, that will avoid corrupting the card with an unsafe removal. I've had to do this with USB drives and sticks in the past as well.

My PRS1 760 has a screen that flashes something like "Do not remove card writing data" when you tuen it on, I never really looked after I woke up as it's on the bedside, and by the time i get the P10 off I presume it's done.

Hope that helps.

Thanks! 

Anyway it's a US$3.54 alternative with free shipping from <link to dealextreme removed> if anyone is interested.


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