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GeneralRe: How to Recover Deleted Files Pin
David Crow29-Apr-04 3:49
David Crow29-Apr-04 3:49 
GeneralRe: How to Recover Deleted Files Pin
jk chan29-Apr-04 4:12
jk chan29-Apr-04 4:12 
GeneralRe: How to Recover Deleted Files Pin
toxcct29-Apr-04 4:18
toxcct29-Apr-04 4:18 
GeneralRe: How to Recover Deleted Files Pin
jk chan29-Apr-04 17:02
jk chan29-Apr-04 17:02 
GeneralRe: How to Recover Deleted Files Pin
toxcct29-Apr-04 19:28
toxcct29-Apr-04 19:28 
GeneralRe: How to Recover Deleted Files Pin
David Crow29-Apr-04 4:41
David Crow29-Apr-04 4:41 
GeneralRe: How to Recover Deleted Files Pin
jk chan29-Apr-04 22:40
jk chan29-Apr-04 22:40 
GeneralRe: How to Recover Deleted Files Pin
Santanu Lahiri30-Apr-04 8:46
Santanu Lahiri30-Apr-04 8:46 
Used to be in the good ole DOS days, Undelete was one option. However, in addition to renaming the first letter back to the original letter, it also did several other things:

First, the directory entry for the file also held the starting cluster number on the HD, as well as the total file size.

Then it calculated the number of clusters needed to contain the file completely (the last partial cluster was upgraded to a whole cluster).

Lastly it went through the FAT, starting with the first cluster, and started linking the required number of clusters into a chain. The odd twist in the whole thing was that the entries were 12-bits wide, so two FAT entries were coded into a three byte field, and had to be decoded accordingly.

This should explain why Undelete worked only part of the time. If you did not run it immediately after deleting a file, chances of recovering the file decreased drastically.

Now, in more modern times, we have several different File Systems, like FAT32 (well, people still use it), NTFS, and maybe HPFS. They all have their own way of tracking the sectors/clusters used by each file. From what I have seen of NTFS, the storage scheme used some sort of an index node mechanism, I was given to understand it may have been a derivative of the Digital's VAX storage architecture. Admittedly, I did not find any documentation on this. No, I did not delve as deeply into this as I did for DOS. In addition, these OSes use temp files that can't be moved physically, and so on. Plus, there are now things such as RAID and so on.

The only reason I can see you would want to muck with such low-level stuff is that you are writing a data recovery program, or you are writing a defragmentation program.
GeneralVB Scripting in MFC Pin
soundman3229-Apr-04 1:21
soundman3229-Apr-04 1:21 
GeneralRe: VB Scripting in MFC Pin
David Crow29-Apr-04 2:04
David Crow29-Apr-04 2:04 
GeneralRe: VB Scripting in MFC Pin
Mike Dimmick29-Apr-04 2:22
Mike Dimmick29-Apr-04 2:22 
QuestionDon't we have any article on Dialogic based project??? Pin
Jigar Mehta29-Apr-04 0:51
Jigar Mehta29-Apr-04 0:51 
AnswerRe: Don't we have any article on Dialogic based project??? Pin
Trollslayer29-Apr-04 1:01
mentorTrollslayer29-Apr-04 1:01 
GeneralRe: Don't we have any article on Dialogic based project??? Pin
Michael P Butler29-Apr-04 2:50
Michael P Butler29-Apr-04 2:50 
AnswerRe: Don't we have any article on Dialogic based project??? Pin
Michael P Butler29-Apr-04 2:46
Michael P Butler29-Apr-04 2:46 
Questioncan we know whether our dll is registered or not Pin
softp_vc28-Apr-04 23:46
softp_vc28-Apr-04 23:46 
AnswerRe: can we know whether our dll is registered or not Pin
David Crow29-Apr-04 2:08
David Crow29-Apr-04 2:08 
GeneralRe: can we know whether our dll is registered or not Pin
softp_vc30-Apr-04 23:23
softp_vc30-Apr-04 23:23 
GeneralSTL Deque Container - question Pin
CoolVini28-Apr-04 23:38
CoolVini28-Apr-04 23:38 
GeneralRe: STL Deque Container - question Pin
Paul Ranson29-Apr-04 0:24
Paul Ranson29-Apr-04 0:24 
GeneralRe: STL Deque Container - question Pin
CoolVini29-Apr-04 4:31
CoolVini29-Apr-04 4:31 
GeneralRe: STL Deque Container - question Pin
Paul Ranson29-Apr-04 11:22
Paul Ranson29-Apr-04 11:22 
GeneralRe: STL Deque Container - question Pin
CoolVini29-Apr-04 22:34
CoolVini29-Apr-04 22:34 
GeneralHTML Dialog question ... Pin
Hadi Rezaee28-Apr-04 23:29
Hadi Rezaee28-Apr-04 23:29 
GeneralDll & Vectors Pin
Bernhard28-Apr-04 23:10
Bernhard28-Apr-04 23:10 

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