copyinf a file with more then one data stream

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A

aa

downloaded an application programme from the vendor's site as a zip file.
When attempting to copy it in a flash memory stick a warning pops up saying
that that zip file contains more then one data stream but the destination
volume does not support this feature. Some data will not be preserved as a
result.

What are these more then one data streams and will the destination file
become unusable if I proceed with copying?
 
aa said:
downloaded an application programme from the vendor's site as a zip file.
When attempting to copy it in a flash memory stick a warning pops up saying
that that zip file contains more then one data stream but the destination
volume does not support this feature. Some data will not be preserved as a
result.

What are these more then one data streams and will the destination file
become unusable if I proceed with copying?
Click to expand...

In a nutshell:

http://www.google.ca/search?q="more...s=org.mozilla:en-US:official&client=firefox-a
 
In
aa said:
downloaded an application programme from the vendor's site as a zip
file. When attempting to copy it in a flash memory stick a warning
pops up saying that that zip file contains more then one data stream
but the destination volume does not support this feature. Some data
will not be preserved as a result.

What are these more then one data streams and will the destination
file become unusable if I proceed with copying?
Click to expand...

No. The datastreams are "extra" information that goes along with the file/s.
It's informative stuff and not executable and has no affect on execution.
The original program will still run and will not be affected.
Actually, you can probably see what's in the datastreams by looking at the
file's Properties under the Summary tab. (Highlight file, right click,
choose Properties, then the Summary tab)

Only NTFS file systems can handle alternate data streams so copying a file
to any location that's not NTFS (CD, DVD, floppy, FAT, etc. etc.) causes the
datastreams to be lost. No functionality of the core executable will be
lost.

HTH,

Twayne`


http://support.microsoft.com/kb/105763
http://www.ntfs.com/ntfs-multiple.htm
 
aa said:
downloaded an application programme from the vendor's site as a zip file.
When attempting to copy it in a flash memory stick a warning pops up saying
that that zip file contains more then one data stream but the destination
volume does not support this feature. Some data will not be preserved as a
result.

What are these more then one data streams and will the destination file
become unusable if I proceed with copying?
Click to expand...

Alternate data streams are a feature of NTFS file systems.

http://en.wikipedia.org/wiki/Alternate_data_stream

There isn't really a good reason to be doing something like
that inside a ZIP file, for the reason that you've discovered.
If your USB stick was FAT32, that doesn't support the alternate
data stream, so unzipping to the FAT32 device means losing
the alternate data stream. Which might actually be a good thing,
depending on your point of view.

An example of where that was used extensively, was the MacOS.
Back in the day, it had a "resource fork" and a "data fork" for
each file, but one of the forks can have zero length without a problem.
The system tools in MacOS are aware of these forks, so they're
not as "hidden" as in NTFS. ResEdit could examine the resource
fork, and an executable program would likely have both forks.
While a vanilla text file would only have a data form.

(Example of looking at the resource fork on a Mac - an alternate data stream)

http://www.hampa.ch/pce/pics/macplus-apps/pce-mac-resedit.png

One example where an alternate data stream were used, was some
version of Kaspersky AV software. Kaspersky stored some attribute
per file in an alternate data stream on each file. I think it
allowed them to track some properties of the files, like detecting
whether they'd been modified, and whether as a result, the file
needed to be scanned. At the time, this caused grief for a
small number of their customers. The file system apparently
didn't always like what they were doing. I think they eventually
fixed it, so there was less grumbling.

http://2kevin.net/datastreams.html

"Kaspersky used to use ADS to store hash data for files,
but they stopped using them in early 2006."

(The "Streams" program from Sysinternals)

http://technet.microsoft.com/en-ca/sysinternals/bb897440.aspx

Paul
 
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