Why is the memory specified on SD/MMC not all available

[jdoherty76]

Can some one please tell me why when you buy a memory card you never get the amount of memory specified available to you. For example I have a 32MB card but the XDA only shows this as 30.9, a bit of a bummer as I originally bought the card for Rom upgrades but had to use a 64MB instead. Does anyone know why this is the case.

PS I am surprised that there is not a declaimer when buying these. Something like “Though this card is 32MB in size there is no guarantee that the full 32MB will be available to you”
Thanks John.
:) :)

[Biso007]

For each storage media, there is a part taken to keep track of the place and attributes of each stored file. This can range from 1% for simple media like SD and MMC to around 15% for highly protected media like RAID5 storage disks.

As a practic, always subtract 1% of the capacity or you can take the job of keeping this FAT area in your diary :lol:

[Rudegar]

sd stand for secure digital which mean that each byte have encryption possiblities this also takes up room

with harddisks it's often because they state the size in bytes and not GB or MB or what ever and to get a KB you need 1024 bytes
but i do believe that flashcards do it the more real way by stating the size in MB and GB and such

[cruisin-thru]

Yes, 500 megabytes is often not 500x1024 but 500x1000 which also accounts for the disparity.