A sparse file is a file who's internally unused internal ranges are not allocated to any actual disk space. These ranges will read as NULL (0) when applications read them and will be allocated only when written to. Since eMule partfiles are mostly unused space initially, substantial amounts of free space can be temporarily reclaimed for other uses. This only works if you're using NTFS (NT File System) the disadvantage of this is that this leads to [file fragmentation].
e.g.Option enabled on 700 MB file , start download of 9 MB at position 300 MB -> 9 MB is allocated on disk. -> filesize is 309 MB.
- The reverse or this option is to allocate full file size on the start of download. e.g.Option enabled on 700 MB file , start download of 9 MB at position 300 MB -> 700 MB is allocated on disk. Filesize is 700MB
- The normal behavior is to allocate space from the beginning of the file till the part that starts downloading. both options disabled/fat on 700 MB , start download of 9 MB at position 300 MB -> 309 MB is allocated on disk. filesize is 309 MB
- on vista with 0.47c mods you might have troubles writing files > 1.7 GB under vista. Disable sparse files there.