Defraging a CD-RW

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cranheim

I use a CD-RW disk to store backup files. I update the files on this backup
disk from time to time. Because of this, I suspect the data on the disk is
probably fragmented. If I were to do a disk copy from this backup disk to a
new clean formatted CD-RW disk, would my newly created disk be "de-fragged"?
I can probably run defrag against the disk itself, but if I remember
correctly, I tried this once before and it took forever, and my not have
even completed. I want to use the safest way to end up with a clean,
defragged backup disk. Thanks for any input. Charles Ranheim
 
cranheim said:
I use a CD-RW disk to store backup files. I update the files on
this backup disk from time to time. Because of this, I suspect the
data on the disk is probably fragmented. If I were to do a disk
copy from this backup disk to a new clean formatted CD-RW disk,
would my newly created disk be "de-fragged"? I can probably run
defrag against the disk itself, but if I remember correctly, I
tried this once before and it took forever, and my not have even
completed. I want to use the safest way to end up with a clean,
defragged backup disk. Thanks for any input. Charles Ranheim
Click to expand...

Leave it alone - it is not fragmented.
If you want a "clean" CD-RW (and you are obviously using packet-writing
software) - then...

- Copy all data from the CD (we are not talking much here) to your PC in a
folder.
- Use the same software you are using to write to said CD to format the CD
completely.
- Copy the data back to the CD.

As extra safety - burn yourself a CD-R and put it elsewhere.
 
Sun, 26 Feb 2006 15:53:16 GMT from cranheim
I use a CD-RW disk to store backup files. I update the files on this backup
disk from time to time. Because of this, I suspect the data on the disk is
probably fragmented.
Click to expand...

They're not. There's no such thing as erasing one file, and therefore
there's no way for a gap to open up. It's those gaps from erased
files that create fragmentation on a hard drive.
 
I hear what you guys are saying, but I still don't understand why a rotating
CD does not act like a rotating C drive. If I have multiple folders on the
backup CD-RW, and I add more data files to one of the folders, won't that
folder need more track space and have to put this new data somewhere else?
The folder would be fragmented. Likewise, if I were to delete some files in
a folder from the CD-RW, wouldn't this create a "hole" that can be used by
some other data file? What am I missing? Charles Ranheim
 
With Nero InCD and Roxio Drag-To-Disk you certainly can delete only one
file. I can see where the O/P is coming from. I know of no way to
check/defrag a rewritable CD or DVD.

--


Regards,

Richard Urban
Microsoft MVP Windows Shell/User

Quote from George Ankner:
If you knew as much as you think you know,
You would realize that you don't know what you thought you knew!
 
It would seem that a multi session RW might be fragmented. If so, the only
way I know to "defrag" is to collect all the contents in a burner program,
make a backup or image, and rerecord the RW. I always thought that each
individual session could not be fragmented, but I've been known to be wrong
on rare occasions. <G>

Richard Urban said:
With Nero InCD and Roxio Drag-To-Disk you certainly can delete only one
file. I can see where the O/P is coming from. I know of no way to
check/defrag a rewritable CD or DVD.

--


Regards,

Richard Urban
Microsoft MVP Windows Shell/User

Quote from George Ankner:
If you knew as much as you think you know,
You would realize that you don't know what you thought you knew!
Click to expand...
 
Sun, 26 Feb 2006 17:39:25 -0500 from Richard Urban
With Nero InCD and Roxio Drag-To-Disk you certainly can delete only one
file. I can see where the O/P is coming from. I know of no way to
check/defrag a rewritable CD or DVD.
Click to expand...

Unless I'm mistaken, you can _appear_ to delete one file, but it's
still there on the disk. There's just an index entry somewhere that
says the file is deleted, or else the index simply doesn't include
that file.

Again, unless I'm mistaken, nothing gets erased from a CD-RW unless
you erase or reformat it.

If I'm wrong about this, I'd love to get a reference to the correct
information.
 
I have been writing many hundreds of megabytes to a single CD-RW disk for
about 1/1/2 years now. I have never erased or formatted the disk. New files
just overwrite the old files, just like on a hard drive. If the new file is
a bit larger than would fit into the same space occupied by the old file, I
guess it goes somewhere else. Then the "pointer" for the old file is
eliminated. If there is not enough contiguous space for the complete new
file, guess what will happen. Fragmentation.

So again, I can see where the O/P is coming from.

--


Regards,

Richard Urban
Microsoft MVP Windows Shell/User

Quote from George Ankner:
If you knew as much as you think you know,
You would realize that you don't know what you thought you knew!
 
I made a comment where I thought I tried defragging a CD before, but after
thinking about it some more, it may have been a Zip drive, not a CD. It
still seems like when a CD-RW file gets updated causing a change in byte
count, the serial track will change length, just as it does on the C drive.
I understand when a file is deleted, the data is still there, but the space
is marked as available (a hole), and can be used by another record. I don't
see the difference in transferring all the data from the original CD disk to
the C drive, then writing it back to new CD, vs just doing a disk copy from
CD to CD-RW to defrag the data. On a disk copy, I would think the software
doing the copying (CD to CD) is using the C drive as a buffer, which would
automatically defrag the data on the read before writing it to it
destination drive. One other dumb question, in the statement: "I can see
where the O/P is coming from", what does O/P stand for? Charles Ranheim


Richard Urban said:
I have been writing many hundreds of megabytes to a single CD-RW disk for
about 1/1/2 years now. I have never erased or formatted the disk. New files
just overwrite the old files, just like on a hard drive. If the new file is
a bit larger than would fit into the same space occupied by the old file, I
guess it goes somewhere else. Then the "pointer" for the old file is
eliminated. If there is not enough contiguous space for the complete new
file, guess what will happen. Fragmentation.

So again, I can see where the O/P is coming from.

--


Regards,

Richard Urban
Microsoft MVP Windows Shell/User

Quote from George Ankner:
If you knew as much as you think you know,
You would realize that you don't know what you thought you knew!
Click to expand...
 
You must format the cdrw or dvdrw in order to defrag it.

Yes RW media DO get fraggemented as you logicaly assume they are.
 
packet RW technology like in INCD by nero has fragmentation since it is like
a hard disk writting files , erasing files then writting new files in their
place.
All this writting and deleting does cause fragmentation and the only
solution is to format the RW medium.

Other RW technology that erases the whole disk and then you write on top of
that does not have fragmentation, this is the way you write a RW media from
the Nero main application (not packet writting).



--
Disclaimer: This info is given "as is".
If you do not like the content or attitude of my posts,
please put me on your ignore list or dont read my posts.

--
cranheim said:
I made a comment where I thought I tried defragging a CD before, but after
thinking about it some more, it may have been a Zip drive, not a CD. It
still seems like when a CD-RW file gets updated causing a change in byte
count, the serial track will change length, just as it does on the C drive.
I understand when a file is deleted, the data is still there, but the space
is marked as available (a hole), and can be used by another record. I don't
see the difference in transferring all the data from the original CD disk
to the C drive, then writing it back to new CD, vs just doing a disk copy
from CD to CD-RW to defrag the data. On a disk copy, I would think the
software doing the copying (CD to CD) is using the C drive as a buffer,
which would automatically defrag the data on the read before writing it to
it destination drive. One other dumb question, in the statement: "I can
see where the O/P is coming from", what does O/P stand for? Charles Ranheim
Click to expand...
 
Original Poster!

--


Regards,

Richard Urban
Microsoft MVP Windows Shell/User

Quote from George Ankner:
If you knew as much as you think you know,
You would realize that you don't know what you thought you knew!

cranheim said:
I made a comment where I thought I tried defragging a CD before, but after
thinking about it some more, it may have been a Zip drive, not a CD. It
still seems like when a CD-RW file gets updated causing a change in byte
count, the serial track will change length, just as it does on the C drive.
I understand when a file is deleted, the data is still there, but the space
is marked as available (a hole), and can be used by another record. I don't
see the difference in transferring all the data from the original CD disk
to the C drive, then writing it back to new CD, vs just doing a disk copy
from CD to CD-RW to defrag the data. On a disk copy, I would think the
software doing the copying (CD to CD) is using the C drive as a buffer,
which would automatically defrag the data on the read before writing it to
it destination drive. One other dumb question, in the statement: "I can
see where the O/P is coming from", what does O/P stand for? Charles Ranheim
Click to expand...
 
I did the following test in an attempt to see if I was losing space on my CD
due to fragmentation. It went as follows: I will call the disk in question
"A", and a blank formatted CD-RW, "B". Before transferring any data to disk
B, the byte status was:
Disk A: Total space 533mb, space used 393mb, remaining space 141mb
Disk B: Total space 529mb.
After the transfer using copy and paste, CD to CD-RW, the new disk B
contained:
Space used 393mb, remaining space 137mb.
This shows no detectable loss of disk space on the original disk I had be
using over and over to update files. The remaining space on the new disk was
4mb less because the total space happened to be 4mb less. One disk was a
Maxell, the other a Sony. I just wanted to pass this along for whatever it
is worth to anyone.
Charles Ranheim
 
Fragmentation happens because no space is wasted as disks are written to;
any file that will not fit into the largest contiguous empty drive space is
written as two or more fragments. You can have either efficient use of
space OR contiguous files, not both as disk contents change.
Defragementation does not change the amount of free space. What it does is
rearrange the fragmented files contiguously. Net result in available
space - no change.

Phil Weldon

|I did the following test in an attempt to see if I was losing space on my
CD
| due to fragmentation. It went as follows: I will call the disk in question
| "A", and a blank formatted CD-RW, "B". Before transferring any data to
disk
| B, the byte status was:
| Disk A: Total space 533mb, space used 393mb, remaining space 141mb
| Disk B: Total space 529mb.
| After the transfer using copy and paste, CD to CD-RW, the new disk B
| contained:
| Space used 393mb, remaining space 137mb.
| This shows no detectable loss of disk space on the original disk I had be
| using over and over to update files. The remaining space on the new disk
was
| 4mb less because the total space happened to be 4mb less. One disk was a
| Maxell, the other a Sony. I just wanted to pass this along for whatever it
| is worth to anyone.
| Charles Ranheim
|
|
| "John Jay Smith" <-> wrote in message
| | > You must format the cdrw or dvdrw in order to defrag it.
| >
| > Yes RW media DO get fraggemented as you logicaly assume they are.
| >
| >
| >
| > --
| > Disclaimer: This info is given "as is".
| > If you do not like the content or attitude of my posts,
| > please put me on your ignore list or dont read my posts.
| >
| > --
| > | >>I use a CD-RW disk to store backup files. I update the files on this
| >>backup disk from time to time. Because of this, I suspect the data on
the
| >>disk is probably fragmented. If I were to do a disk copy from this
backup
| >>disk to a new clean formatted CD-RW disk, would my newly created disk be
| >>"de-fragged"? I can probably run defrag against the disk itself, but if
I
| >>remember correctly, I tried this once before and it took forever, and my
| >>not have even completed. I want to use the safest way to end up with a
| >>clean, defragged backup disk. Thanks for any input. Charles Ranheim
| >>
| >
| >
|
|
 
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