Talk:Extent (file systems)

message: Shouldn't the definition of "extent" include "the entire scope of the boundaries (of something)"?
Shortylumber 17:28, 5 September 2006 (UTC)
thread_title:  extent 

message: The Volume Table of Contents (VTOC) on an MVS volume, describes
space assigned to data sets (files, in more common terminology),
free space, and even its own size in terms of extents.
Rlhamil 16:27, 26 March 2007 (UTC)
thread_title:  VTOCs on MVS, z/OS, etc 

message: Is it really valid to list NTFS here?  The described method requires the developer to perform file writes in a specific manner to make this happen.  In my opinion this doesn't make NTFS qualify as an extent based file system.  I believe that in order for a FS to qualify it must perform this task automatically; if we're going to allow this as part of the definition then nearly any file system should be able to make it to this list.  For example, one could make nearly any file system pre-allocate space by using comparable calls.  It should also be noted that the specified Win32 API calls do NOT guarantee that this space be contiguous!  The system will try to make the space contiguous but it might not be possible, so I really believe that by these standards literally any file system could be put on this list, and therefore NTFS should be removed.  —Preceding unsigned comment added by 24.222.116.189 (talk) 11:51, 2 January 2008 (UTC)
replies: text: I just wanted to add that it looks like NTFS was removed from the list (probably rightly so), but the file system matrix on the following wiki page still shows the contrary: http://en.wikipedia.org/wiki/Comparison_of_file_systems --May 8, 2008  —Preceding unsigned comment added by 99.201.204.33 (talk) 18:00, 8 May 2008 (UTC)
replies: text: NTFS addresses file data in extents, rather than in individual blocks like ext3, but it doesn't automatically preallocate.  Frankly, I'm not sure how it or any other file system could reasonably expected to do this, because it doesn't know what the required size will be, and preallocating too much space would tend to _increase_ fragmentation. 166.70.56.217 (talk) 01:45, 30 November 2008 (UTC)
replies: text: Actually, NTFS seems to use $Bitmap to mark blocks as allocated. So if file with 100 000 blocks is being allocated, looks like NTFS would need to toggle 100 000 bits in $Bitmap to address changes to allocation, so there is change for every block needed. Which is fairly slow operation. If this design is "extent-based", ext2 is definitely extent-based as well as there is nothing prevents filesystem driver from trying to allocate several contigious blocks in one shot, writing blocks in a grouped manner as well. More recent designs who considered to be "extent based" usually do not employ allocation bitmaps and would rather write extent structure describing space allocation as range "blocks 1 to 100 000 are now used by..." (which is faster than toggling 100 000 bits) and then readjust free/busy space indexes (in some b-trees, etc).
Ive added NTFS. It does use extents but microsoft refers the extents as runs. I found this out in the inside windows 2000 book written by mark russinovoch and david soloman.--Thunderpenguin (talk) 14:12, 3 December 2008 (UTC)

text: They seems to have something different in mind when it comes to definition of extents. Basically, I would refuse to call any bitmap-based filesystem design as extent based since each bit have to be toggled for each block, making it a old-style block-based design who does not takes benefits of addressing data via large extents defined in a compact structure. As for me, such definition of extent is flawed.
It IS however unnecessary to add SQL server, as all modern versions of Windows use NTFS anyway.
You might as well say Windows 7, Vista and XP!  —Preceding unsigned comment added by 192.55.54.38 (talk) 19:18, 12 November 2010 (UTC)
thread_title:  NTFS 

message: "Physical Extents" and "Logical Extents" --Jerome Potts (talk) 00:44, 15 March 2013 (UTC)
thread_title:  what about LVM and DB/2? 

message: Is there a solid reason why there was a __NOTOC__ on this article? The article is not that short. If not, there's really no reason to add it. Chininazu12 (talk) 12:17, 26 July 2016 (UTC)
thread_title:  NOTOC?