View Full Version : Size on Disk

10-01-2002, 10:18 AM
I've just been looking at the properties of my Downloads folder, and I noticed that the folder size is something like 680mb, yet the size on disk is more like 695mb. Why is this?

I found one folder that was 1.4gb, yet size on disk was closer to 2gb... have I got heaps of wasted space somewhere?

10-01-2002, 10:29 AM
This has stumped me too however I don't think it's wasted space.

10-01-2002, 10:40 AM
Dont quote me on this one

But I think it has a bit to do with block vs file sizes.

eg: if your blocks on your disk are 16k but a particular file is 9 it uses one 16k block leaving 7 over. Multiply that out with lots of file in a folder and boom lots of empty space, and because files will not share a block on you HDD, hey presto.

Plus I think windows now reports both sizes it has become more obvious to people.

How does it go, I think thats it but I may be so far wrong someone should just shoot me!!!!

10-01-2002, 10:53 AM
Nope you hit the nail pretty much on the head Tazzie :-)

There are a couple of things you can do to free up some of this invisible disk space.

1) If you havent already (and god knows why) convert your HD to FAT32, this uses 16Kb blocks, whereas FAT16 uses 32Kb blocks.

2) Defrag, if you have a file spread over 10 blocks, yet each block only has 15Kb filled up there is 10Kb of slack space being wasted that Defragging will help to free up

10-01-2002, 04:16 PM
Depends too on the information you are looking at. Sometimes a folder or disk size is given in bytes and sometimes in Mega or Giga bytes. Remember that a Mb is 1024 bytes and a Gb is 1024 Mb or 1,048,576 bytes, so for instance if I look at the free space on my c drive I get results of 3,144,085,504 bytes or 2.92 Gb, which are the same thing but look totally different (drive manufaturers use the bigger number to make the size look bigger - buyer beware!).

10-01-2002, 04:21 PM
whoops, Igot those numbers wrong didn't I? 1024 bytes is 1Kilobyte (Kb), 1,048,576 bytes is 1 Mb, and 1,073,741,824 bytes is 1 Gb (which looks like 73 Mb more than it really is!)
Sorry about that!-

10-01-2002, 05:11 PM
Yeah, the minimum amount of disk space a file can use is one cluster. A one-character file will occupy 16kB or 32kB or whatever your cluster size is. (On a floppy it's only 512 bytes, fortunately).

As for MB measures, it's even worse than that. Various people have used various measures (usually to make their product look better). Some hard disk manufacturers gave a 'raw' capacity which ignored the gaps between sectors before formatting. And a MB was often a decimal million.

IBM did the oddest one, which is still around. Ever wondered why MS now says that a 1.44MB floppy holds only 1.3something?

1 KB = 1024B. According to IBM, from the first days they made disks, 1 MB = 1000 kB. That's where the 1.44 MB size of a 3.5' floppy (and 1.2 MB of a 5.25' floppy) comes from.

MS used to agree with IBM, but now seemed to have adopted the international standard of 2^20 (a binary million) bytes per megabyte.

10-01-2002, 09:49 PM
Shouldn't have made any difference, Ray, as it listed the size in MB and the size on disk as MB, so they're both in the same units.