I'm not sure where it stores this index data but it just does, and it doesnt impact on the wear and tear.
So, the memory management keeps a track of where it recorded the last sector and next time will write data to a different place - therefore evening out the wear across the whole card. In reality this can take a long time but in theory you need to be aware of it when managing the memory. After that it starts to age quickly and may not work. Now the tricky part - each sector has a life of approx 100,000 writes (numbers may be higher today). Therefore the software will wait until it has a sector's worth of data before writing. Nowadays this is all handled internally on the card so the programmer shouldn't have to worry too much about it.īack then (and I'm sure it is similar today), each sector of the card is treated as a common part - write to one byte and you write to the whole sector. We were logging hundreds of data items at 1min intervals and kept 1 month of data - managing the storage on the CF was tricky. One probelm we faced was memory management of the card. I did some work on embedded micros many years ago (Windows CE) and we used Compact Flash cards for storing logged data.
My memory on this is a but fuzzy, but here's what I recall and my thoughts on formatting. Still, I'd be wary that all of the data on a 32 GB card is actually being erased in 10 seconds. (Max write speed on the G10 is something like 6 to 9 MB per second.) Perhaps entire sectors can be reset to zero electronically - this would be faster than actually transferring zero data to all areas of the card. It's not clear how such operations could be completed in several seconds over the much slower SD card interface.
These operations take a very long time on standard hard disks. In modern computing, low-level formatting is supposed to identify/flag bad blocks and (optionally) reinitialize all data areas on the device. And yes, it does put zeros in all of the memory, erasing all data. It does not take very long to Low Level Format these memory cards. Minutes is definitely not the case, and I am talking about Low Level format, and not Format. But, I have the SD880, and I have low level formatted 32 GB SDHC Class 6 memory cards (Transcend), and it typically takes only around 10 seconds, perhaps. I don't know specifically about the G10 and formatting. Either the manual is incorrect, or it's not erasing everything. If that's so, it would take over 22 minutes to fill an 8GB card with zeros, assuming the G10 can write 6MB sec (which may be optimistic). The G10 manual states that a low level format takes 2 or 3 minutes. Low Level format fills all the space on the card with Zeros so if you sell the card with the camera, the buyer can't use "photo-recovery" to find all the cheeky pics of the missus in the bath.
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