Formatting. What does it actually do?

sandiego69

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I keep getting reminders to format the SD card but my understanding of computers says that a format will completely wipe the card/drive and reinitialise ready for use.

As it only seems to take a matter of seconds, is the existing data and files left intact. I am thinking specifically of the speedcam files.

So, back to my original question, why do we need to format?
 
Regular format? Nothing, just removes the indexes/allocation table with everything (videos/photos) still in the card.
If you do low level format, then it rewrites card with zeroes.
 
it is possible to recover data that has been "formatted" when you do a quick format you are just deleting the map to the file, the file for all intents and purposes still exists...kinda, on magnetic media such as HDDs its even possible to recover data recorded many times over, ive recovered data that's been overwritten more than 5 times, I believe the NSA suggests more than 8 times to be "sure"
 
From experience with dashcams formatting the card is very important, the card is is very heavy use and being overwritten multiple times per day at times. If i had a pound for every time in the past we had a customer try and find footage of an event and couldn't find any because the card had corrupted possibly because it had never been formatted i wouldn't be rich but i would have a much fatter wallet!

That's why the reminder on a Thinkware was designed to be annoying to make you format the card! At least it can be formatted from the camera and doesnt have to be put into a PC to do it like a lot of cameras.
 
From experience with dashcams formatting the card is very important, the card is is very heavy use and being overwritten multiple times per day at times. If i had a pound for every time in the past we had a customer try and find footage of an event and couldn't find any because the card had corrupted possibly because it had never been formatted i wouldn't be rich but i would have a much fatter wallet!

That's why the reminder on a Thinkware was designed to be annoying to make you format the card! At least it can be formatted from the camera and doesnt have to be put into a PC to do it like a lot of cameras.

yeah, the issue is to do with how often a piece of the card gets hammered by IOPS. if you don't delete stuff you will end up with portions of the card that are used more often than others, take for example our "partitioned" cards, firstly they are not partitioned at all, the whole card is just one single partition divided up with folder size limitations, but those folders are not actual physically sectioned off areas of the card, they are all mixed together, some of those areas are hit more than other areas, free space is prioritised over used space as you go about recording data you might end up with a fragmented mess with portions of the file here there and everywhere, all it takes is for one portion of the card to become corrupt and suddenly you end up with a useless file.

There is no load balancing on SD cards as you find on SSDs so it is really important to "balance" it yourself by formatting it as often as possible.
 
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