can CHDK harm the memory card?

fudgey

1705
a570is

Re: can CHDK harm the memory card?

« Reply #10 on: 02 / May / 2008, 09:48:32 »

Advertisements

Btw, is SD card write protection done in the reader hardware or does it in the operating system? If it's in the OS, we could just patch or configure the Linux kernel to disregrad it...

As for harming memory cards, Flash memory has limited write/erase cycle lifetime. It varies but it may typically be in the order of 100000 writes. That's plenty for normal camera use, even when juiced up with CHDK. But it would very easy to modify CHDK to constantly overwrite some small file on the card, be it for debug purposes or for a kludgy way to communicate via USB by reading/writing to a file cunningly named a JPG. This kind of things would make CHDK wear out cards faster.

How often is the CHDK configuration file updated? Each time you change something in the menus?

Logged

PhyrePhoX

2254
make RAW not WAR

Re: can CHDK harm the memory card?

« Reply #11 on: 02 / May / 2008, 09:51:34 »

each time you exit alt mode it is saved, when something changed, afaik

Logged

Flickr*
www.PhyreWorX.de
CHDK News @ Twitter

fe50

3147
IXUS50 & 860, SX10 Star WARs-Star RAWs

Re: can CHDK harm the memory card?

« Reply #12 on: 02 / May / 2008, 16:37:05 »

Quote from: fudgey on 02 / May / 2008, 09:48:32

...
As for harming memory cards, Flash memory has limited write/erase cycle lifetime. It varies but it may typically be in the order of 100000 writes. That's plenty for normal camera use, even when juiced up with CHDK. But it would very easy to modify CHDK to constantly overwrite some small file on the card, be it for debug purposes or for a kludgy way to communicate via USB by reading/writing to a file cunningly named a JPG. This kind of things would make CHDK wear out cards faster.
...

It seems to be not a problem - the flash chips has intelligent algorithms to avoid / handle defect cells, e.g by using reserve cells or bypassing to healthier cells.

In the german c't magazine they made tests with writing up to 16 million times on the same logical adress without any problems. The tests has been carried out with USB sticks, but they said the flash chips on SD cards handle this the same way.
"Flash-Haltbarkeit" on c't FAQ

For some information about SD cards and the flash chips inside i've attached a sample datasheet...

Jeou Luen-FlashMemorySDCardDataSheet.pdf (361.58 kB - downloaded 189 times.)

Logged

-->FIRMWARE DUMPS<-- * Manual * Lua * me

wontolla

413
S3 & G9 & A720

Re: can CHDK harm the memory card?

« Reply #13 on: 07 / May / 2008, 12:38:14 »

SDCardReader.JPG (182.66 kB, 800x600 - viewed 177 times.)

WriteProtectionSwitch.JPG (47.73 kB, 800x600 - viewed 248 times.)

BeforeModification.JPG (136.74 kB, 800x600 - viewed 266 times.)

AfterModification.JPG (137.52 kB, 800x600 - viewed 286 times.)
Model:Canon PowerShot S3 IS Exposure Time:25/10 seconds F Number:F/2.7 Date Taken:2008:05:03 01:48:51 Metering Mode:Pattern Flash Mode: Focal Length:6 mm Color Space:sRGB

Logged

fbonomi

469
A570IS SD1100/Ixus80

Re: can CHDK harm the memory card?

« Reply #14 on: 07 / May / 2008, 12:50:18 »

oh, thanks for the pics. I will try that too when I have a second reader.

and remaining on damages "caused" by CHDK, the thing that really worries me is the little door of the camera, the one that you open to get the card out. At least on my 570, it looks poorly built, not done to opened and closed 50 times a day :-)

Logged

vine

124
A560

Re: can CHDK harm the memory card?

« Reply #15 on: 07 / May / 2008, 12:57:50 »

Quote from: fbonomi on 07 / May / 2008, 12:50:18

oh, thanks for the pics. I will try that too when I have a second reader.

and remaining on damages "caused" by CHDK, the thing that really worries me is the little door of the camera, the one that you open to get the card out. At least on my 570, it looks poorly built, not done to opened and closed 50 times a day :-)

I know exactly what you mean. I have the exact same fear with my A560