UNC paths vs mapped drives in CVS Emacs

UNC paths vs mapped drives in CVS Emacs

[Mathias Dahl]

(I posted this to the emacs for windows newsgroup first but
got no comments and I still *suspect* that this is a bug so
I'll try here too)

I have been using Emacs 21.3 for a long time on Windows NT4 and
Windows 2000 and often opened files using their UNC paths, like this:

Find file: //myserver/myshare/myfile.txt

Now I am using the CVS version of Emacs, and it still *works* but
veeery slowly. Navigating to the file is quick enough, but when I open
it there seems to be a long delay.

If I map the share to a letter, like this:

c:\> net use z: \\myserver\myshare\myfile.txt

and opens file from that mapped "drive", it is as snappy as it was
before.

I have tried starting emacs with --no-init-file, but the
same thing happens.

Anyone got any clue to why it work like this?

/Mathias

Re: UNC paths vs mapped drives in CVS Emacs

[Mathias Dahl]

Mathias Dahl <brakjoller@gmail.com> writes:

> I have been using Emacs 21.3 for a long time on Windows NT4 and
> Windows 2000 and often opened files using their UNC paths, like this:
> 
> Find file: //myserver/myshare/myfile.txt
> 
> Now I am using the CVS version of Emacs, and it still *works* but
> veeery slowly. Navigating to the file is quick enough, but when I open
> it there seems to be a long delay.
> 
> If I map the share to a letter, like this:
> 
> c:\> net use z: \\myserver\myshare\myfile.txt
> 
> and opens file from that mapped "drive", it is as snappy as it was
> before.

Just to help others that may have this problem I will post some
information I just found by searching the net:

* It seems the reason for the slowness is some extra checks that emacs
  does regarding version control. I'm not sure about the exact cause
  though.

* A workaround until it is fixed is to do this:

  (setq vc-handled-backends '(RCS CVS SVN SCCS))

  In my case, I just left CVS and SVN in there. If you do not use any
  VC software I guess you can set it to null.

* If you want the full story, follow this link:

  http://lists.gnu.org/archive/cgi-bin/namazu.cgi?query=Slow+access+to+files+using+UNC+path&submit=Search%21&idxname=emacs-devel&max=100&result=normal&sort=date%3Aearly

 (sorry for the incredibly long URL, but using those query parameters
 gives a good overview)

/Mathias