To format or not to format?, that is the question.

[MisterE]

I personally prefer formatting cards, as MisterE has pointed out, apart from anything else, its much quicker, but as mentioned by others, I have always done it in camera, not via the card reader/computer.

That's a point I forgot to make. In camera formatting - never on the PC. Thanks Yv.

 

[hollis_f]

Just deleteing files and leaving others on a card is eventually going to create fragmented images on it. Just as a Hard Drive needs to be de-fragmented to prevent it eventually throwing it's hands up in horror when it can no longer cope the same could happen with a card if left in a similar state. If you don't mind risking the possiblity of losing images then fine, myself, after I've transferred them to the PC and backups the card is reformatted.

There are many reasons for formatting a card in the camera before each session, but fragmentation ain't one of them. Indeed the files on a CF card are deliberately fragmented by the controller. Let me explain....

The reason that fragmented files on a hard drive tend to slow things down is because the heads that read the data has to physically move - which takes time. So, to access a fragmented file (or to write a new file into fragmented space), the read head will have to move to each section of the disk that contains bits of that file. That can take several times longer than the actual reading of the data. So the defragmentation process takes all the bits of the file and sticks them in one (or a few) neighbouring bits of the HDD - thus minimising the amount of movement the head requires.

But with a CF card there are no moving bits. It takes just about the same amount of time to access data in neighbouring bits as it does with the data spread all over the place. So fragmentation isn't a problem. Then there's the fact that solid-state memory has a limited number of read/write cycles. If the data was always written to the start of the card then that area would get used up pretty damn quickly and start producing errors. So the CF controller uses something called wear-levelling. This spreads the data writes over all the available space on the card.

Solid-State Drives use the same sort of wear-levelling for the same reasons. Defragging an SSD is pointless and just writes loads of data, reducing its life. Win7 has defragging on by default for all hard drives (so those who say they don't use it may not be correct). But it switches off , also automatically, for SSDs.

Oh, Macs also handle file fragmentation automatically, although they do say that some users may find they need to do it themselves as well.

 

[cjay]

Where on earth did you get that from?

Sorry, but that sounds like the kind of hearsay I get on the phone at my work when someone tries to tell ME how to do MY job - total garbage.

It's interesting - as ever it depends on what card the OP is talking about. In most cards there is no direct access from the pins you see to the memory chips you can find if you pop off the cap (the abomination that is xD excepted).

Apologies if you know this already.

In all SD(HC/XC) cards in normal stream/block read/write there is a microprocessor sitting between you and the pins, performing wear levelling and block remapping. As such the physical format should make no difference. Only at the margins where sufficient blocks are mapped out and as a result the card is nearing capacity and starting to spend longer searching for the next good block. The downside of the controller insulating you from the physical device is it is at liberty to optimise certain access patterns over others - eg random access 4K block reads will be slow but if accessing contiguous 4K blocks it can stripe access and gain a speed-up for subsequent blocks.

As it is usually formatted for FAT32 then the properties of FAT32 come into play. FAT unfortunately doesn't have a mechanism to prevent, on newly created files, fragmentation within a partition. This is because the FAT has to be scanned (linearly) to determine which blocks can be used.
So if you don't format, and importantly, partially delete, files can easily require several non-contiguous blocks.

For a camera with a marginal (as in the class of the card 2/4/6/8/10 is at the limit for the application) card and particularly applications with a stream profile (video for ex.) then formatting the card will make a difference on whether a sustained write (up to the capacity of the card) can succeed or not.

C

 

[Daysleeper40]

I have three bodies and about 20 cards..

Makes you sound like an international man of mystery... or someone with multiple personalities and a penchant for store cards.

I always format my cards in camera after I have transferred any efforts that I actually want to keep to my PC. Only caused trouble once when I mistakenly formatted one of my OH's cards. He tends to save up his pics until he has loads on a card before he does anything with them... I think he even had shots from last years holiday on there. Managed to recover all of them though so it was all good.

 

[Mikesphotaes]

So Diskeeper 8 is a total waste of money ? on XP that sets a timed schedule to defrag while you work, i know some of you will know this.
I never bought the said software but i installed it on my desktop and it sometimes slowed me down as it ran.

It was the quickest of all the defraggers I've tried but then they brought out 9 or 10, which ran all the bleedin time!