PDA

View Full Version : when format to ntfs does data get overwritten?



gareith
17-09-2002, 09:01 AM
hello

when you format a partition to ntfs that was currently fat32, does ntfs formatting destroy all data on the partition, or does it only affect the first part of the disk with the fat on it?

ta

NathanTheKind
17-09-2002, 09:09 AM
Formating will destroy any data that is currently on the Harddrive. If you format from FAT32 to NTSF then all the data on that Partiton will be lost. like wise if you do it the other way round. and also if you format FAT to FAT and NTSF and NTSF

Cheers

:)

Merlin
17-09-2002, 10:00 AM
No the data does not get overwritten at format time.
Without getting too deep when formatting a drive/partition from FAT to NTFS,
The DOS File Allocation Table is overwritten (thus removing the FAT directory to sectors containing file headers.

The NTFS index directories are written mapping to sectors (for all intends and purposes known as formating).



The only times file sectors are overwritten is:
using a disk utility to specifically do that task, and
writing a file to sectors previously used.
Providing the above two actions are not done, data recovery of accidently deleted files/partitions is possible. M$ has several articles relating to this.



As with all formatting, the larger the partition/drive the longer the time to format (map to sectors) the partition/drive.

wuppo
17-09-2002, 11:04 AM
If you are using winXP, the convert utility will convert FAT32 to NTFS non-destructively. As always, when undertaking a major disk operation, it pays to backup at least your important files beforehand.

Chilling_Silence
17-09-2002, 03:19 PM
Formatting to NTFS = YES!
Converting to NTFS = Nope
Only thing is, As Far As I Know, 98 and 95, maybe ME too don't like the NTFS file system so dual booting wouldn't work to my knowledge. Correct me if I'm wrong.
But for regular install, do a convert!

Merlin
17-09-2002, 06:22 PM
Elaboration.

Though the data (as with the data written on the hard drive) does not get overwritten at format time, the signposts to where the data is stored are replaced.

Files are just data stored on a drive and there can be big files and small files.
Sectors are a unit of storage.



Working backwards, data is stored in sectors. The first part of the sector is a reference to what is in that particular sector. Then the data. And finally whether that is all the data or if there is more stored elsewhere (and where).
Since files can be big and stored in several sectors, the last part of each sector contains a reference (signpost) to the next sector containing the next part of the file.
Consequently, the file (data) start location is an important one since it is the one referenced first. Without knowing where to locate the first sector of a file, the file is effectively lost and inaccessable.


The File Allocation Table (FAT) is where the references to all data first sectors are located. The FAT also contains a directory of the partition of logical drive.
Have directory (map) and references to data first sectors (signposts) - have organised access.
Remove the FAT - the data is still there - just not accessable. The partition still exists but the data appears to have disappeared. Restore the FAT and data access is also restored.


But wait - there is more.


The Master Boot Record is located in the first sector of a hard disk. The very last part of the first sector is reserved for the partition information. This is the information that is recorded when using a partitioning program - like MS Fdisk.
The information here includes the location of the partition on a hard drive, the size in sectors, the partition type and if it is bootable.
Remove the partition information and the FAT is not accessable and so the data is inaccessable also. Restore the partiton info and access to data is regained.


So when formatting in DOS occurs, the FAT is replaced with a new copy - ergo the data is still on the hard disk, just not accessable. Ditto for NTFS - either when converting or formatting.


The only times file sectors are overwritten is:
using a disk utility to specifically do that task, and
deleting a file then writing a new file to sectors previously used.



How else do data recovery programmes work?