Thread: Create File of X size

Originally Posted by jcas1411

my bad.. was formated fat32.. df reports ntfs correctly

got excited there for a moment...

Ehm, but fat32 should also give correct free-size...

--
Mats

my bad.. ntfs in linux isnt broken.. had a fat32 drive in.. sparse files fool fat32 but not ntfs..

in Windows the CreateFile method is actually creating a handler for direct disk IO.. that is what I really want to do in Linux..

sorry for the double post.. didnt see that it went to page 2

Originally Posted by jcas1411

found my own answer.. maybe

Windows uses unbuffered disk IO whereas Linux uses unbuffered file IO

http://www.developer.com/net/cplus/a...0919_2119781_5

nice help how to do on either platform via C

Both Windows and Linux normally uses buffered I/O - although memory cards/USB sticks are "unbuffered" because people tend to pull them out at almost any time - and it helps if half the data wasn't left dangling in the computers memory [that applies for WinXP onwards, pre-XP the buffering was done for all devices whcih is why you HAVE to "eject" a drive in Win2K etc, but not in WinXP].

Both Linux and Windows also allow you to add flags when opening a file to say "do not buffer this" (that is the basic OS level file-functions, what the upper layer C or C++ library does with this capability is a different story).

--
Mats

>>>>>.... to create a file with an exact size x
Did anybody consider to try ftruncate(), ftruncate64()?