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I received my 1gb memory stick today, and though I noticed this a long time ago I finally got around to asking about it. It says it holds a gig of info, though on my computer and the PSP, it says 980mb or so available. Even though I format it and what not it still doesn't say 1gb available. Same thing with all my sticks, the 32mb one says 30mb available; The 512mb says 489mb available. I know there are two locked files on it but it says they are Zero kb.

Thanks in advance...

980, thats pretty good. i would have expected it to be a 960. if you have own a computer, you will notice that goes for the same for pc hdd. they say 40gb hdd. but you really get a 34-37gb hdd. they are never what they say. also if you check you default psp mc, it says 32mb, but its really only 30mb. its just the way its always been, so there isnt much you can do.

Thanks...

The advertised size of disks is usually given as unformatted, simply because it sounds bigger. Once you have a file system on there some of this is used just to keep track of the files, thats where the space goes.

Also, not sure if it still happens but i remember some disks being measured and labelled as 1 mb = 1000^2 bytes, not 1024^2 bytes, so again the os sees it as smaller than the label, but maybe not in this case

For memory sticks, t's more likely that problem is the FAT file system consuming some space, including the file allocation table, etc.
It probably is still 1024 * 1024 * 1024 bytes of raw unformatted space.

I'm surprised it says 980m available actually and not 976.

Storage space is (deceptively) indeed calculated with a meg being 1000x1000 bytes. At least they do so for HD's so I assume MS to be the same.

So a 32mb stick is 32.000.000 bytes which gives (divided by 1024x1024)=30.51 Mb.
Likewise 512 mb stick gives 488.28 mb.

Now a gig...I dunno if they take 1000 or 1024 Mb for that but assuming it'd be 1024 I'd end up at 976.56 Mb.

0xdf

Sony Memory Stick Duo 32MB -> 32473088 Bytes (~31MB)
SanDisk Memory Stick PRO Duo 512MB -> 491782144 Bytes (469MB)
SanDisk Memory Stick PRO Duo 1.0GB -> 997195776 Bytes (951MB)
SanDisk Ultra II Memory Stick PRO Duo 1.0GB -> 997195776 Bytes (951MB)

Then the fs must hold 24 elements per 1024 elements managed?

The calculation has held up (accurately) for all my harddisks till now.

0xdf

Well I was just guessing because I had already put movies and didn't want to erase them to see the capacity. A brain fart because there are other ways to see the capacity... (stupid noob...) Anyway my guess was off, by about... alot. 949.7mb is the capacity of my card. Which sucks cause I get stiffed by about 50mb of storage...