I purchased a 1gb memory card today and only have 980mb of free memory on it! surely 1gb equates to 1024mb. where has 44mb dissapeared to?

The same with my 120gb harddrive i only had 111 gb free? thats 9gb missing!
Surely they should advertise it as what you actually get and not some made up figure.

With hard drives a certain % is taken-up with the actual directory structure and FAT, so you never get 100% of the disk to use, but the memory should be 100% available unless they have a similar "index" area.

It's been this way for decades. The Commodore 64 only had 39k available to the user, despite the advertising saying it had 64Kb of RAM.

Storage manufacturers tend to class 1000 bytes as a kilobyte, rather than the proper 1024, its the same with hard drives. So its actually smaller before you even start, Plus whatever the FAT takes up.

Joel

What people don't understand (and should be explained in the shop) is that the memory in your computer isn't just used by stuff you run, the actual operating system needs some memory too, so you will never have the entire memory available for you to use.

When they say you need 512K to run XP, they mean just for the computer to work properly, you need more memory still for your programs and stuff.

Flash memory cards however, should be 100% available I think unless they have some kind of index area.

Just to make things even nicer, what you and I actually think of as a megabyte is called a Mebibyte (http://en.wikipedia.org/wiki/Mebibyte) in some circles - the wikipedia article linked claims the IEEE and others are strongly pushing for that to be the official word. Technically, scientific units have always given mega as meaning 1000 of course... It's one of those things that nobody worried too much about when hard drives were 100 MB or so, but you can of course "lose" a significant amount with drives of several hundred gigs. Drive manufacturers are always very careful to define their megabytes explicitly.

It will have an index that is taking up some of the free memory, put it into a usb card reader and you'll find that it all ready contains some information that the manufacturer has put onto it.

Best manufacturer of SD cards is SANDISK or KINGSTON TECH. See http://uk.insight.com/index.php

Aside from the various advice on memory sizes and the 1024/1000 discrepancy, I thought I'd throw this one in; do you have an on board graphics adapter enabled (even if you're not using it)? These can take up anything from 8 to 64Mb of 'shared memory' which is never available to apps.

Just a thought :)