Minimum file size

  • Thread starter Thread starter Peter Morris [Droopy eyes software]
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Peter Morris [Droopy eyes software]

Hi all

If I write a 1 byte file to my SDRam storage card, what is the mimimum space
consumed? Ie, the minimum "disk" allocation size?

Thanks

Pete
 
Peter Morris said:
Hi all
Click to expand...

Hi Peter,
If I write a 1 byte file to my SDRam storage card, what is the mimimum space
consumed? Ie, the minimum "disk" allocation size?
Click to expand...

it depends on the blocksize with which the card was formatted. e.g. 4KB,
8KB, 16KB (sizes from FAT)
If one file is allocated, it's always rounded up to the next blocking size.

Regards,
Gustavo
 
There may also be a consideration for the way in which the card marks
blocks as being 'expired'. SDRam supports a finite number of re-writes,
and as a block or whatever reaches the end of it's reusable life it is
marked as no longer available. For efficiency, this is not usually done
on the 'byte' size but as a block. As this occurs, the capacity of the
SD card can appear to be reduced.

So if you were repeatedly creating/deleting a 1 byte file a high number
of times, you could expect to see a swifter reduction in life
expectancy/capacity.

The SanDisk website has some interesting papers on this topic.

Chris
 
Ah, I was unaware of this, thanks for pointing it out. I shall in that case
continue along the line of saving all objects to a single file stream only
when needed.

Thanks

Pete
 
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