Re: Nikon unveils the highly anticipated Z8 camera!
groob wrote:
snapsy wrote:
I have a running Z8/Z9 tech container thread on Dpreview, where I share various technical details of the camera you may not find elsewhere. You can read it here. I just posted about how CFE card "full formats" work. Below is the content of that post:
When you format a CFE card inside the camera, the UI presents you two options:
* Full Format
* Quick Format
The documentation recommends a full format "for users who wish to ensure that all data are deleted or who feel that the speed at which the camera reads from and writes to the card has slowed and wish to improve data transfer speeds"
Based on this description and the fact that a full format completes in just a handful of seconds it's clear that Nikon is performing an NVMe sanitize operation, which electrically erases the NAND pages, both the mapping table and the actual user data blocks. Previous incarnations of this were termed a "secure erase".
Unlike magnetic data, NAND cells can't be ovewritten in place. The only way to change the contents of a user-addressable block is to write the new data to a fresh NAND page (one that's in an erased state). The NAND page holding the previous version of the data will be marked as "not in use" in a mapping table - that page will be erased/reclaimed by the card whenever it starts running out of fresh NAND pages. The host controller (camera in this case) can expedite the process by issuing an NVMe Deallocate command to the user-addressable block (aka Trim command), which will erase/reclaim the block either immediately or during the next idle period.
It's not clear if Nikon issues Deallocate commands when erasing images in camera. If it doesn't then you definitely want to use a "Full Format" frequently, otherwise you'll run into performance issues, esp on cards that you fill to capacity often.
What effect do we think this will have on recovering photos from a formatted card? I know it has been possible in previous generation cards and cameras. Is this formatting different and more “thorough” (for lack of a better word)?
A full format in the camera will irrevocably erase all the data on the card. The format you're referring to is a filesystem format, which typically only erases the meta-data in the file system, leaving the actual contents of the files intact. In that case, the files can be reconstructed by scanning the media looking for data that appears to be images and then re-creating the image files in the filesystem around that data. Presumably, the quick format option in the camera performs only a filesystem format.
Jul 08, 2023 at 06:45 AM
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