[tex-live] Pretest installation failed

[Reinhard Kotucha]

On 2016-05-31 at 21:42:09 +0200, Bernhard Kleine wrote:

 > The installation failed independently of whether the Avira firewall
 > was on or off.

Avira is a virus scanner, not a firewall.  Bernhard, I'm sure that you
know this and you used the term "firewall" unintended.

To make it clear: There are two kinds of virus scanners, those which
hook into system calls like write() and examine everything written to
the disk, and those which scan files which are on the disk already
asynchronously.

The former are harmless but the latter usually lock directories
(revoke write permissions from directories temporarily) and thus
interfere with TeX Live installations.  In most cases locking
directories is not a problem, but TeX Live installs more than 100,000
files, hence clashes are unavoidable.

Virus scanners which scan the disk asynchronously can always be
disabled temporarily because they detect viruses too late anyway.

On the other hand, disabling a scanner which tracks system calls is
neither necessary nor advisable.  It doesn't interfere with TeX Live.

But the most important thing: NEVER DISABLE A FIREWALL!  It takes a
fraction of a second and your computer is ruled by others.  If you
examine the log files of your firewall, you'll be amazed how many
people are on the waiting list.  Again, NEVER DISABLE A FIREWALL!

I'm emphasizing this because it happened in the past that people
accidentally used the term "firewall" instead of "virus scanner" and
recommended to turn off the firewall while installing TeX Live.
Definitely not a good idea...  NEVER DISABLE A FIREWALL!  NEVER!


AFAIK, unlike many other scanners, the Avirus virus scanner doesn't
lock directories and thus doesn't interfere with a TeX Live
installation.


Regards,
  Reinhard

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Reinhard Kotucha                            Phone: +49-511-3373112
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