Re: Re: NtCreateFile and STATUS_OBJECT_PATH_NOT_FOUND (0x0000003A)

> If I can impose further with one more question - I have noticed that, in
> addition to "\Device\CdRom0", the cdrom can be referenced as
> "\\.\GLOBALROOT\Device\CdRom0".  I am a bit confused as to the nature of
> GLOBALROOT.  Is there any significance to the GLOBALROOT identifier, and
> are there any other devices that hang off it that I need to worry about??

That is a Windows NT thing, not Xbox.  In Win32, the CreateFile API call
does not directly access the root of the NT namespace - kernel32.dll uses
ObDosDevices and translates to NtCreateFile.  However, there is a "back
door" in this mechanism.  \\.\ in Win32 means to open any object that is in
\?? aka \DosDevices.  There are many symbolic links there, like LPT1, so you
can open \\.\LPT1 with CreateFile.  The notation \\.\ looks like a UNC path
with "yourself" as the computer name, but it isn't the same as putting your
computer's name there.  GLOBALROOT is a symbolic link to \, the root of the
NT namespace.  In other words, \??\GLOBALROOT is a symlink to \.  This
allows you to open any file object in the NT namespace using CreateFile,
without having to bypass it and directly call NtCreateFile.  (This means
that GLOBALROOT is rather useless if you are using NtCreateFile.  GLOBALROOT
does not exist on Xbox.)

The following things can be used to open the CD-ROM in regular NT using
CreateFile (not NtCreateFile):

\\.\D:  (open local drive letter D:, which is a symlink to the drive)
\\.\CdRom0  (open symlink; there are CdRom0, etc. symlinks inside \??)
\\.\GLOBALROOT\Device\CdRom0  (access CD-ROM from its native NT path)

> Again, many thanks for the detailed explanations.  It makes so much more
> sense now...

You're welcome =^_^=

Melissa



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