Not directly Cygwin: Windows special filenames

Not directly Cygwin: Windows special filenames

[Shaddy Baddah]

Hi,

I am familiar with the DOS names like \\.\c: to get at a raw partition
from Windows command shell, that would be the equivalent of something
like /dev/sda1 in Cygwin.

Does anyone know of an equivalent for accessing the whole disk, i.e. the
equivalent of:

[snip]
/dev/sda	\device\harddisk0\partition0	(whole disk)
[/snip]

from http://www.cygwin.com/cygwin-ug-net/using-specialnames.html. I
often look for clues on this page, and I get that there might be a
syntax that includes \device\harddisk0\partition0 that does the job.

Indeed cygpath -m /dev/sda or /dev/sda1 return the equivalents from this
page. Is this misleading, seeing as they are not really valid DOS names?

Thanks in advance,
Shaddy

Re: Not directly Cygwin: Windows special filenames

[Shaddy Baddah]

Hi again,

On 7/31/2006 2:11 PM, Shaddy Baddah wrote:
> Indeed cygpath -m /dev/sda or /dev/sda1 return the equivalents from this
> page. Is this misleading, seeing as they are not really valid DOS names?

Sorry, that was a little presumptions of me. Are paths such as 
\device\harddisk0\partition0. When I try to open a file to this path, it 
is not recognised as valid.

Does it live in the same namespace, so to speak, as C:, 
\\suchandsuchserver, etc?

That's where I am coming from in terms of an expectation of what cygwin 
-w would return.

Thanks in advance,
Shaddy

Re: Not directly Cygwin: Windows special filenames

[Corinna Vinschen]

On Jul 31 14:32, Shaddy Baddah wrote:
> Hi again,
> 
> On 7/31/2006 2:11 PM, Shaddy Baddah wrote:
> >Indeed cygpath -m /dev/sda or /dev/sda1 return the equivalents from this
> >page. Is this misleading, seeing as they are not really valid DOS names?
> 
> Sorry, that was a little presumptions of me. Are paths such as 
> \device\harddisk0\partition0. When I try to open a file to this path, it 
> is not recognised as valid.

These are not valid paths in the DOS namespace.  It's an NT native
device name which is mapped to \\.\physicaldrive0 in DOS.  See
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/fs/querydosdevice.asp
and
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/fs/createfile.asp
and
http://www.sysinternals.com/Utilities/WinObj.html

> Does it live in the same namespace, so to speak, as C:, 
> \\suchandsuchserver, etc?
> 
> That's where I am coming from in terms of an expectation of what cygwin 
> -w would return.

I guess you mean cygpath -w.  Well, these are the paths used in Cygwin
internally since Cygwin uses the native API to access disk and tape
devices.  cygpath calls Cygwin functions which just translate between
the POSIX paths and the DOS/NT paths used internally.  It does not do
the extra step of recreating the DOS device names from the NT device
names.  This would be especially tricky in case of Harddisk names
because Cygwin uses paths which are not used for the DOS device mapping.

If you want cygpath to create the correct Windows equivalents,
http://cygwin.com/acronyms/#SHTDI and http://cygwin.com/acronyms/#PTC


Corinna
[who has that feeling this is an off-topic discussion for cygwin-talk]

Re: Not directly Cygwin: Windows special filenames

[Igor Peshansky]

On Mon, 31 Jul 2006, Shaddy Baddah wrote:

> Hi again,
>
> On 7/31/2006 2:11 PM, Shaddy Baddah wrote:
> > Indeed cygpath -m /dev/sda or /dev/sda1 return the equivalents from this
> > page. Is this misleading, seeing as they are not really valid DOS names?
>
> Sorry, that was a little presumptions of me. Are paths such as
> \device\harddisk0\partition0. When I try to open a file to this path, it is
> not recognised as valid.
>
> Does it live in the same namespace, so to speak, as C:, \\suchandsuchserver,
> etc?

I would imagine you'd need to use '\\.\device\harddisk0\partition0', but
MSDN is not particularly forthcoming on this issue...

> That's where I am coming from in terms of an expectation of what cygwin
> -w would return.

I take it you mean "cygpath -w"...  Yes, I suppose one would expect to be
able to use the exact output of "cygpath -w" to open the equivalent
Windows file/device...  PTC, of course.
	Igor
-- 
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Re: Not directly Cygwin: Windows special filenames

[Shaddy Baddah]

Hi,

First, I would like to apologise for all the errors (grammatical, 
mistype, and dropped wording) in the original email.

On 7/31/2006 8:26 PM, Corinna Vinschen wrote:
> 
> These are not valid paths in the DOS namespace.  It's an NT native
> device name which is mapped to \\.\physicaldrive0 in DOS.  See

Yes, that is exactly what I was looking for. Thank you.

> If you want cygpath to create the correct Windows equivalents,
> http://cygwin.com/acronyms/#SHTDI and http://cygwin.com/acronyms/#PTC

I would love to contribute, unfortunately cannot presently. I will 
however try to forward a suggestion for the Special Filenames section of 
the user manual, that flags the names as not being in the same 
"namespace" as most cygpath -w outputs, if that's ok?

> Corinna
> [who has that feeling this is an off-topic discussion for cygwin-talk]

As in it has become on-topic for cygwin ml, right? I should have 
re-adjusted when the second part of my email touched on cygpath. Sorry 
about that.

Regards,
Shaddy