Defragmentation Research Paper - Techist - Tech Forum

Go Back   Techist - Tech Forum > Computer Software > Microsoft Windows and Software
Click Here to Login
Closed Thread
 
Thread Tools Display Modes
 
Old 03-18-2005, 09:29 AM   #1 (permalink)
Newb Techie
 
Join Date: Mar 2005
Posts: 5
Lightbulb Defragmentation Research Paper

Hi all. I am writing an academic paper on IT architecture and processes from an 'outsider’s perspective' (centred on the idea of innovation - "can’t see the wood for the trees"). Can I ask for some help on the process of defragmentation. With the varying file systems (NTFS, Fat, FAT32) it is difficult to understand how a Defrag program can successfully negotiate disks. I understand the concept of fragmented data, how it becomes fragmented, and know how, in general, a defrag is supposed to help. However, can someone explain to me in detail, or give me any advise/help/URL's as to how a defrag program really works:: from the pushing of the defrag button (so to speak)
How does it identify fragmented files?
How does it locate fragmented files?
How does it store this information?
What is the defragmentation process? eg. Scan, document, relocate?
Is there any information already stored about fragmented files on a day to day basis, or is it one clean scan when defrag is run?
Are there separate processes depending on the Filing system/OS system?
Where are indexes and lookup tables located, and how are these referenced?


This paper is referenced on the basis of helpfulness of response and this site/people will be properly referenced. - Maxmadx@hotmail.com for E-mails to be included in its general release.

Thanks.
__________________

stevenhales is offline  
Old 03-18-2005, 12:10 PM   #2 (permalink)
Newb Techie
 
Join Date: Feb 2005
Posts: 29
Default

I would recomend good ol google.
__________________

jirwin is offline  
Old 03-18-2005, 03:52 PM   #3 (permalink)
Wizard Techie
 
Jorsoft's Avatar
 
Join Date: Feb 2004
Location: Oakdale, MN
Posts: 4,581
Default

Just thinking about how Defrag works gives me a headache. I need some tylenol. Try a google search like jirwin suggested.
__________________
Jorsoft is offline  
Old 03-18-2005, 04:11 PM   #4 (permalink)
True Techie
 
Join Date: Jan 2005
Posts: 153
Default

It analyzes everything that creats a temp data template I think.

Then it uses the analyzation to find the data.

If you look at the percentage bar, it sometimes jumps from 27 percent all the way to 60 %. The huge gap is probably the lag in reading what to defrag next.
__________________
<strong><font size="2.2"><a href="http://vistarewired.com/2007/03/14/10-things-you-wished-you-had-known-about-vista/"> 10 must-know Vista tips and tutorials</a></font></strong>
<p>
crazlunatic is offline  
Old 03-18-2005, 04:56 PM   #5 (permalink)
Ultra Techie
 
Join Date: Jan 2005
Posts: 849
Send a message via Yahoo to ZeroX
Default

here ya go

http://computer.howstuffworks.com/question548.htm
__________________
<a href=\"http://www.spreadfirefox.com/?q=affiliates&amp;id=0&amp;t=62\"><img border=\"0\" alt=\"Get Firefox!\" title=\"Get Firefox!\" src=\"http://sfx-images.mozilla.org/affiliates/Buttons/110x32/take.gif\"/></a>
<a href=\"http://www.spreadfirefox.com/?q=affiliates&amp;id=0&amp;t=181\"><img border=\"0\" alt=\"Get Thunderbird!\" title=\"Get Thunderbird!\" src=\"http://sfx-images.mozilla.org/affiliates/thunderbird/thunderbird_small.png\"/></a>
<a href=\"http://my.opera.com/USERNAME/affiliate/\" title=\"Download Opera\" ><img src=\"http://promote.opera.com/small/opera88x31.png\" width=\"88\" height=\"31\" alt=\"Download Opera\" /></a>
ZeroX is offline  
Old 03-18-2005, 11:25 PM   #6 (permalink)
Wizard Techie
 
Join Date: Apr 2004
Posts: 3,247
Default

k, here is an indepth (hopefully you can catch the meaning and I dont get alot wrong, but if memory serves this is true in all counts). First, understand how a file is writen. You have the hard drive and on there is a file system that knows the size of said hard drive. It sees the hard disk as a string, like 000000000 to ZZZZZZZZZZ or whatever. This is called Logical Cluster Number (LCN) and will start at 00000000 and end at ZZZZZZZZZZ. When an app creates a file the MFT (master file table) indexes it and contains a pointer to its location on the hard drive by its location via the LCN. The MFT contains the pointer of were the file data starts and where it ends on the drive (somewhere between 000000 and zzzzzzz, think your seeing a trend here ). Anyhow, the ideal way of containment is for it to by contiguous, or start from one point and all data be contained in one chunk. However, over time what happens is the files become fragmented. So now, you have the MFT containing multiple indexes. So that said program will start at one point according to the MFT and then stop... say... midway, then continue elsewhere on the HDD. Well, the MFT contains pointers in the index on where the files are, so if it is fragmented it will have several starting indexes for the same program. What happens is defrag reads first the index, lays out a map of the HDD and figures where all files for the programs on the HDD are scattered at. It then will reorganize the HDD to put the abruptly cut off files from a fragmented state to a contiguous state. Defrag knows where these files that are scattered all over are located due to the MFT pointer in the index pointing to them.

Defrag also has to have a decent amount of HDD space left, reason is two fold. It uses the space to save info that needs to be manipulated, and also save the info of the file that is about to be shifted. As in, say you have a fragmented file that must be inserted where a contiguous file already exists. Well, the fragmented file is stored, the contiguous file is stored, the fragmented file is put where the old contiguous file is and the contiguous file is placed accordingly. Usually this bumps the next segment of data and it dominoes. Think about it like cutting in line. You cant just put something somewhere that is already occupied. So, you have to make room. Its hard to explain this without diagrams and pics, but hopefully you get the gist.
__________________
If you argue with an idiot he will drag you down to his level and beat you with experience.

I am not a fast writer.
I am not a slow writer.
I am a half-fast writer.

-Robert Asprin
killians45 is offline  
Old 03-19-2005, 02:58 AM   #7 (permalink)
Ultra Techie
 
Join Date: Jan 2005
Posts: 849
Send a message via Yahoo to ZeroX
Default

man you have alot of time on your hands
__________________
<a href=\"http://www.spreadfirefox.com/?q=affiliates&amp;id=0&amp;t=62\"><img border=\"0\" alt=\"Get Firefox!\" title=\"Get Firefox!\" src=\"http://sfx-images.mozilla.org/affiliates/Buttons/110x32/take.gif\"/></a>
<a href=\"http://www.spreadfirefox.com/?q=affiliates&amp;id=0&amp;t=181\"><img border=\"0\" alt=\"Get Thunderbird!\" title=\"Get Thunderbird!\" src=\"http://sfx-images.mozilla.org/affiliates/thunderbird/thunderbird_small.png\"/></a>
<a href=\"http://my.opera.com/USERNAME/affiliate/\" title=\"Download Opera\" ><img src=\"http://promote.opera.com/small/opera88x31.png\" width=\"88\" height=\"31\" alt=\"Download Opera\" /></a>
ZeroX is offline  
Old 03-20-2005, 06:53 PM   #8 (permalink)
Wizard Techie
 
Join Date: Apr 2004
Posts: 3,247
Default

heh, whats sad is I'm at work
__________________
If you argue with an idiot he will drag you down to his level and beat you with experience.

I am not a fast writer.
I am not a slow writer.
I am a half-fast writer.

-Robert Asprin
killians45 is offline  
Old 03-21-2005, 09:55 AM   #9 (permalink)
Monster Techie
 
HoLoCroN's Avatar
 
Join Date: Mar 2004
Location: Plant City, FL
Posts: 1,305
Default

Good job finding these resources! Keep up the good work.
HoLoCroN is offline  
Old 03-22-2005, 04:14 AM   #10 (permalink)
Newb Techie
 
Join Date: Mar 2005
Posts: 5
Default

Thank you all for your responses. Great forum.
__________________

stevenhales is offline  
Closed Thread

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 01:31 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.