Tracing a copied file...

I have several CDs that contain a specific file. Only one of the CDs
was used to make another copy of this specific file on a separate CD.
Is there an easy way to analyze the copied file/CD to see which CD it
was copied from?

On 16 Oct 2005 06:22:16 -0700, jody7818@yahoo.com wrote:

>I have several CDs that contain a specific file. Only one of the CDs
>was used to make another copy of this specific file on a separate CD.
>Is there an easy way to analyze the copied file/CD to see which CD it
>was copied from?

Maybe.

Check the "slack" space at the end of the file on each CD and if they
are different then you can compare that to the same on the copy and if
one of them matches you know which one it came from.

What do you mean by "checking the slack at the end of the file"?

jody7818@yahoo.com writes:
> What do you mean by "checking the slack at the end of the file"?

Disks store data in blocks of a given size. (e.g. 1kB blocks).

Files are not always even multiples of that size.

Slack space is the amount of space in the final block of a file that
is not really used for real data by the file.

--
Todd H.
http://www.toddh.net/

On 16 Oct 2005 08:42:56 -0700, jody7818@yahoo.com wrote:

>What do you mean by "checking the slack at the end of the file"?

http://www.pcguide.com/ref/hdd/file/partSlack-c.html

http://www.dewassoc.com/kbase/hard_drives/fat_slack.htm

The unused space in a disk cluster. The DOS and Windows file systems
use fixed-size clusters. Even if the actual data being stored requires
less storage than the cluster size, an entire cluster is reserved for
the file. The unused space is called the slack space.

DOS and older Windows systems use a 16-bit file allocation table
(FAT), which results in very large cluster sizes for large partitions.
For example, if the partition size is 2 GB, each cluster will be 32 K.
Even if a file requires only 4 K, the entire 32 K will be allocated,
resulting in 28 K of slack space. Windows 95 OSR 2 and Windows 98
resolve this problem by using a 32-bit FAT (FAT32) that supports
cluster sizes smaller than 1K.

On 16 Oct 2005 08:42:56 -0700, jody7818@yahoo.com wrote:

>What do you mean by "checking the slack at the end of the file"?
http://www.programmersheaven.com/zone16/cat920/3134.htm