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Re: can't access Serial Ports


On Fri, 29 Apr 2005, Eric Blake wrote:

> According to Igor Pechtchanski on 4/28/2005 2:59 PM:
> > /dev is currently a virtual directory in Cygwin.  Try "ls -l /dev/ttyS1"
> > -- you should get a listing.  If you want Tab-completion, or if you want
> > "find /" to look at the devices in /dev, you can create the /dev directory
> > and even populate it with dummy (and real) directory entries -- see
> > <http://www.cygwin.com/cygwin-ug-net/using-specialnames.html> for a script
> > to do this.  Otherwise, don't bother.
>
> Igor, your create devices script is a bit out-of-date; for example, it
> doesn't create /dev/full.

Yes, it's quite a bit out of date.  The list of devices in the script was
created from the Cygwin sources at the time, but I'm sure new devices were
added since.

> And would creating /dev as a managed mount point to
> /cygdrive/?/cygwin/dev allow you to create a dummy /dev/com1?

I haven't tried.  If we switch to a real /dev (see below), we'll either
need to address the /dev/com* issue, or give up support for the non-POSIX
/dev/com* altogether.

> Also, why are you using touch(1) instead of mknod(1)?

The script was written when /dev was just a virtual directory.  Now there
is no need for /dev to be virtual (in fact, for a while I've been using a
parallel /ddev directory on my system with mknod'ed devices, as a test),
but having a real /dev needs two things: turning off the virtual /dev in
the code, and having a script to create all of the devices.  I do have a
not-quite-ready mknod version of the script (in fact, it was requested on
the cygwin-developers list, perhaps we could include it in base-files
later).

> When accessed as /dev/*, the listing is correct, but when accessed via
> /cygdrive/?/cygwin/dev, the difference is apparent.  Compare:

Now, why would you *ever* want to access /dev as /cygdrive/?/cygwin/dev ?
	Igor
-- 
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     |,4-  ) )-,_. ,\ (  `'-'		Igor Pechtchanski, Ph.D.
    '---''(_/--'  `-'\_) fL	a.k.a JaguaR-R-R-r-r-r-.-.-.  Meow!

"The Sun will pass between the Earth and the Moon tonight for a total
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