The file browser shows two different sizes for files. This is due to the fact that when files are stored on a disk, the amount of disk space used is usually greater than the size of the file. This is because disks are divided into clusters and each file takes up a whole number of clusters. The cluster size depends on the type of file system and the size of the disk. For the most common file systems FAT-32 or NTFS, the cluster size is between 512 bytes and 4 Kbytes, which means a 1 byte file could still take up as much space as a 4,096 byte file. If you are running Windows 98, you should be using FAT-32. If you are running Windows NT4, Windows 2000 or Windows XP, you should be using NTFS. However, if you are still using the older file system FAT-16, cluster sizes can reach as much as 32Kbytes, or even more.
It is also possible to have a file that takes up less disk space than the size of the file. This can happen if the file is compressed. Disks using the FAT file system can be set to have the entire drive compressed. Disks using the NTFS file system, which is available under Windows NT4/2000/XP, allow compression to be set on a file by file basis. Note that the compression and decompression of a file is entirely automatic, so the file will appear no different after it is compressed. The only reason for not always using compression is that a compressed file may take very slightly longer to access.
To compress a file using Windows 2000/XP, right click the file icon in Windows Explorer, then select Properties from the menu that pops up. Next select the Advanced button, and then tick the compress-contents box in the Advanced Attributes panel and press OK to compress the file. Whole folders can be compressed by selecting a folder then following the same procedure.