[MacDV] Re: more about the inutility of defragmenting an OS X FS.

[James Asherman]

On Wednesday, December 31, 2003, at 11:47  PM, Steven Rogers wrote:

>
> On Wednesday, December 31, 2003, at 03:23 PM, James Asherman wrote:
>
>>> You don't and can't know how the blocks are laid out on physical 
>>> disk.  You can't know it  because that information doesn't leave the 
>>> disk controller.  The controller maintains a fiction of putting the 
>>> blocks where you ask, but it actually puts the blocks wherever it 
>>> wants to.  . . .
>>
>> I'm not stupid. I know how a disc works and what are the illusions 
>> and what are the realities.  The reality is we need 10's of gigs all 
>> ina row so that we miss not 1/60th of a second of video looking for 
>> someplace new to put it.  . . .
>
> I don't see how you can accept the idea that the positions reported by 
> the controller are not the actual physical positions, and then 
> continue going on about how important defraging is get contiguous 
> space.
>
> SR
>

Because what it is showing me is not really a fiction so much as a 
representation that I can understand.
  Were it a complete fiction it would not take so long to compute or be 
a serious product at all. What I meant was that I understand that just 
because you drop something in a folder that does not represent the true 
realiity and when you look at the map you don't necessarily see all the 
bad blocks. But it definitely cleans up the disc and when the number of 
Mb of contiguouos space goes up after a pass and the map is neater and 
more organized and optimized, that is true . Even if in truth the space 
is not quite contiguouos but the drive controller has decided thatt it 
is a good arrangement it is still better .
Jim