[mdlug] The new "surface" computer

[G Balaji]

On 7/18/07, Robert Adkins <radkins at impelind.com> wrote:
> >
> >
> > All true. I agree.
> >
> > If the NTFS driver is not ADS-aware, then, yes the benefits of ADS washes away.
> > But, similarly, it is true of almost all non-encrypted file systems -
> > if the file system is not running, then there is no security for its'
> > files - the intruder can load his own file system manager, disregard
> > security flags, and steal information.
> >
> > ADS was intended to be used as a small, but important, measure in
> > ensuring overall security of an operating system - but this works only
> > if all other measures are in place and are effective.
> >
> > If not in the original design decisions, at least from the (harsh)
> > lessons learnt, ADS should have been severely restricted - if nothing
> > else, at least in the max size an ADS stream can grow up to.
> >
> > -B.
> >
>
>     I've been doing a little more reading and remembering about some
> File System things.
>
>     Alternative Data Streams is not the same as Metadata.
>
>     Metadata is part of the normal file and can be used to input things
> that the OS can use to determine what kind of file it is looking at.
> This is what Apple did for years with the Mac, even if it had something
> similar to ADS, as I understand it, this isn't what the Metadata is.
>
>     Metadata is like a "header" in a file. In a way this metadata is
> similar to what you see in the first few lines of virtually every single
> Binary format CAD/CAM file. In the first few lines there is plain text
> information telling you the CAD System the file was generated from, what
> version, sometimes this information is more in depth and includes the
> part name/program name for the part the CAD File represents; when I say
> "Program Name" I am saying like the "Code Name" for some new automobile.
>
>     Anyway, what got me thinking about this is some stuff I was reading
> regarding a need for people to start using the metadata features of file
> systems (I believe even FAT32 can do this) to get away from the finite
> combination of the three letter extension. This was talked up regarding
> the metadata capabilities of Linux and certain Desktop Environments.
> It's been a while since I read this stuff so my memory could be slightly
> off.
>
>     -Rob
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True, ADS and meta-data are dis-similar. But, ADS _can_ be used to
store meta-data. And meta-data is not used to store the kind and range
of data an ADS can store.

On the other hand, meta-data is application-specific. The Portable
Network Graphics standard defines allowable meta-data in its file
structure specification. The Java Virtual Machine Specification
defines allowable meta-data in its specification.

But a PNG viewer cannot make sense of a Java class file, and a Java
class decompiler cannot make sense of a PNG file.

And, if the operating system is not made aware of the application to
which a file (extension *) is to be associated with, it has no use for
the meta-data embedded in the files.

* - Although file name extensions are commonly used as "the way" to
determine application affinity, this is another way on the Internet.
>From a web server, one can stream a Java class file - MyClass.class -
with the mime type of image/png and the PNG viewer will be invoked to
view the file (and will fail, of course, even with the 0xCAFEBABE Java
class file indicator in the first few bytes of the file).

-B.