8GB Card coming up 7.1GB??? WTF

JimKarczewski

My old Calumet branded card, 8GB UDMA 333x card died, so I took it back, got a new 420x card. Stuck it in the camera yesterday and noticed only 7.1GB available? (5DII) Stuck it in my reader, just to make sure there wasn't some weird stuff and nope, 7.1GB available?

Tried 2 other Non-Calumet 8GB cards. They came out better, 7.7GB and 7.63GB, but to loose almost 1GB on a card, what gives? Bad data points? Should I take it back and try yet another card and see if it formats higher?

I'm aware there is FileSystem overhead, which is why the other cards are 7.7 and 7.63GB, but almost a whole GB???

sneaky77

try formatting it first see if it may have just be something else going on. Like hidden manufacturer files or stuff like that.

ian408

Before you format it, you might check to see if it has recovery software package on it. If so, download it before you format it.

rsquared

There may also be some differences based on how they defined 1 GB. I'm not sure how the card manufacturers usually do it, but you often see on the back of hard drive pacakges that caveat that 1GB = 1,000,000,000 Bytes. As far as your computer is concerned though 1GB = 1,073,741,824 Bytes (1024 Bytes per KB times 1024 KB per MB times 1024 MB per GB)

If this card is using the 1GB = 1,000,000,000 Bytes calculation, your computer would only see it as 7.45 GB before the filesystem overhead. It looks like your other cards are losing up to about .35GB in overhead, which on this card puts you right down to 7.1 GB, which is what you are seeing.

bluemoon

yeah this often has to do with the manufacturers of the devices as well as the people that create the filesystems, its because they use a 1000 as one KB vs 1024 as one KB

rookieshooter

You always lose 7% of capacity to what rsquared said. My 32GB card is 29.8GB formatted.

41magnum

If I'm not mistaken the manufacture also reserve a portion of the flash type media for failed sectors.