|
|
| Applications |
| Mailing Lists |
| Miscellaneous |
| Operating Systems |
| Programming |
Re: Why ext3 doesn't need defragmentation ?
Date: Fri Nov 30 2007 - 17:53:32 EST
hi ya
> David Brodbeck wrote:
>
> On Nov 30, 2007, at 9:45 AM, Stefan Monnier wrote:
> > No. The NTFS file system does not need defragmentation.
all file systems can use a defragmentor
lets assume a disk format of:
1 2 3 4 5 6 7 8 9 10 ...... 63 ( aka sectors )
if you try to read/write a file starting sector 1 into your disk buffer, you may or may not have disk buffer space left to read another 512Byte from sector 2...
if you wait a bit, few milliseconds for the system to services its disk interrupts, you now have disk buffer space to read sector 2 ..
but since you waited too long, sector 2 came and went, so now you have to wait for a whole revolution before you can read sector 2
if you format using, than you may or may not have time to read sector 2
1 11 21 31 41 51 61 2 12 22 32 42 52 62 3 13 23 33 43 53 63 4 14...
the defragmentor can be used to move sectors around to optimize reading the whole file w/o waiting for the next revolution
- how the defragmentor displays used and unused sectors can make a big difference in the pretty pic you see vs the actual performance
what you see the defragmentor showing would be a continuously allocated file instead of scattered across various sectors within a track or having to move the heads to a different tract to get to the next 512byte
there's only 512bytes per sector
63 sectors per track
and any number of cylinders depending on your disk size
the number of heads and disk buffer size would depend on your disk drive manufacturer and model#
one traack is 512MB * 62 == 31.744KBytes with 16 physical heads .... you can read 509.904KBytes per revolution
all un-used disk sectors belonging to a different file is read and discarded ... what a waste
with 8MB or 16MB disk buffer .. you can read lots of tracks before the disk buffer is full ... there should NOT be a "slow" system
lba ...
maps all the cylinder/heads/sector into other whacky numbers ( lba blocks )
c ya
alvin
-- To UNSUBSCRIBE, email to debian-user-REQUEST@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.orgReceived on Fri Nov 30 18:01:54 2007
This archive was generated by hypermail 2.1.8 : Tue Feb 26 2008 - 13:07:52 EST
|
Contact Us Legal Notices Order Services Online Pantek Home Privacy Policy IT news Site Map Pantek Library |