[tex-live] Installing on Windows from UNC

[T T]

On 28 March 2011 16:08, Robin Fairbairns <Robin.Fairbairns at cl.cam.ac.uk> wrote:
> Martin Schröder <martin at oneiros.de> wrote:
>
>> 2011/3/28 Reinhard Kotucha <reinhard.kotucha at web.de>:
>> > Martin, did you get a reasonable error message from cmd.exe at least?
>>
>> Yeah. :-( Map the remote path to a local drive. :-{
>> I was using remote desktop and tried to install from a local DVD by
>> remote desktop.
>>
>> It seems to be one of the things where Windows tries to be more secure
>> than needed. :-{
>
> nah.  it's one of the things they never thought to bother with; it's
> been the same since the first release of nt4, in my experience.
>
> i would assume that they *really* don't want people using their cr*ppy
> little shell, and discourage potential users by refusing to undertake
> developments.

The reasoning behind this decision of microsofties is quite amusing in
fact (or sad, depending on how you look at it).  Turns out, UNC paths
are forbidden as current directory in cmd.exe (and only there, they
work in other programs!), because of a compatibility issue with
DOS-era programs [1]. DOS programs must get a current drive letter as
a result of the interrupt 19h, but there isn't one for a network
drive.  So, rather than prevent just the DOS programs to run from UNC
paths, Microsoft in all its wisdom decided that it will instead just
cripple the entire command shell.  Bravo, way to go Microsoft.

While it could be in principle possible to make our installer work
from UNC paths (by not relying on the current directory anywhere),
making sure that everything works as expected would be a lot of work
for relatively little benefit.  Not something I will spend my time on.

[1] http://blogs.msdn.com/b/oldnewthing/archive/2007/02/15/1683851.aspx

Cheers,

Tomek