[tex-live] ctan->tl updates caught up

Reinhard Kotucha reinhard.kotucha at web.de
Thu Aug 2 23:50:40 CEST 2012

On 2012-08-02 at 10:45:40 +0100, Philip TAYLOR wrote:

 > Reinhard Kotucha wrote:
 > > If you're using a virus scanner, turn it off while updating TeX Live.
 > Not a valid solution, Reinhard : no Windows user in his or her
 > right mind should voluntarily turn off virus protection; it is the
 > responsibility of the installer to behave correctly in the presence
 > of such protection, not require that it be turned off, temporarily
 > of otherwise.
See below.

 > For what it's worth, I run three anti-virus and anti-malware
 > products concurrently on all my machines, and have /never/ had a
 > problem with a TeX Live install as a result of any or all of them.
 > Of course I have not yet installed TeX Live 2012 (far too early in
 > its release cycle, IMHO) but if TL2012 has problems with concurrent
 > file access that did not exist in earlier versions, then this would
 > represent a major retrograde step.

First of all, the problem is independent of the TeX Live release.  It
solely occurs on Windows, all other platforms supported by TeX Live
allow to run more than one process at the same time.

There are different types of AV programs.  Some are scanning files on
the disk, others hook into system calls and surveil read/write

Only the first category is problematic because file locking is
involved.  On the other hand it probably takes hours to scan the whole
disk, hence viruses are not detected immediately.  Then it doesn't hurt
if the scanner is turned off for a while.

AV programs which hook into system calls don't need to lock any files
and thus don't have to be turned off.  Their advantage is that they
can detect malicious files while they are created or used and can
react immediately.

There were many reports regarding the file locking problem in the past
and I don't remember any case where disabling the virus scanner didn't
help.  If people report this problem in the future, we should ask them
which AV software they are using and maintain a list.  

There are certainly many AV programs available for free which don't
lock files.  Last year I installed TeX Live under Windows and AVIRA
didn't cause any trouble.  It doesn't necessarily mean that it doesn't
lock files, maybe it was busy scanning other parts of the disk during
installation by chance.  And I don't want to ask users to replace
their AV software unless I definitely know that what they have
installed is the culprit.  Therefore I think it's better to maintain a
blacklist rather than a whitelist.

On the other hand, if someone is willing to test AV software
thoroughly, it's feasible to maintain a whitelist too. 

Phil, you also said:

 > Quot homines, tot sententiæ

Sure, but if a program running in the background with higher
privileges prevents other programs from creating/modifying files,
it's a technical problem, not a matter of taste.  You can ask as many
smartasses as you want and everyone has a different opinion indeed.
It would be more helpful if one of those smartasses comes up with a
technical solution rather than telling us his opinion.


Reinhard Kotucha                                      Phone: +49-511-3373112
Marschnerstr. 25
D-30167 Hannover                              mailto:reinhard.kotucha at web.de
Microsoft isn't the answer. Microsoft is the question, and the answer is NO.

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