Why tube amplifiers sound better than solid-state ones

Yes, yes, to be more precise I should’ve said: “Why tube amps sound different than solid-state ones”, but I used the word “better”, because lots of audiophiles prefer the tube (or tube-like) “euphonic” sound πŸ˜‰ One of the usual explanations is even vs odd harmonics, but still it’s not clear why we prefer even harmonics.

These two excerpts make it clear:

Continue reading “Why tube amplifiers sound better than solid-state ones”

Firefox 18.0 crashes on Solaris

Update: fixed in v19.0beta (at least v19.0b1 build3 looks good):
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/ (19b1 does not save sessions, though πŸ˜‰

Firefox 18 (all betas and 18.0) crashes on Solaris 11 and OpenSolaris. The workaround is to set the following variables to “false”:

browser.cache.disk.enable
browser.cache.memory.enable
browser.cache.disk_cache_ssl

See bug 827971.

Simple log-rotator

Non-compressing log-rotator:

# more logrotate.sh
#!/bin/bash
for file in $*
do
mv ${file}.5 ${file}.6
mv ${file}.4 ${file}.5
mv ${file}.3 ${file}.4
mv ${file}.2 ${file}.3
mv ${file}.1 ${file}.2
mv ${file} ${file}.1
touch ${file}
pkill -1 syslog
done

Compressing version:

#!/bin/bash
for file in $*
do
mv ${file}.5.gz ${file}.6.gz
mv ${file}.4.gz ${file}.5.gz
mv ${file}.3.gz ${file}.4.gz
mv ${file}.2.gz ${file}.3.gz
mv ${file}.1.gz ${file}.2.gz
mv ${file} ${file}.1
touch ${file}
pkill -1 syslog
gzip ${file}.1
done

Usage:

# logrotate.sh asa1.log cisco2.log templog
#

One-liners: simple ASA log parsers

Sometimes you do not need a detailed log-analysis but several simple one-liners that you can adjust without too much thinking how it works, what you did last time, etc. The examples below are absolutely NOT optimal, but rather modular for easy line-editing.

1. Allowed traffic:

cat   asa.log | grep permitted | grep access-list |
sed -e 's/^.*permitted//' -e 's/hit-cnt.*$//' |
sed -e 's/([0-9][0-9]*) ->/ ->/' | less

Result:

 tcp outside/10.2.8.30 -> inside/10.1.141.23(8080)
 tcp outside/10.2.8.30 -> inside/10.1.141.23(8080)
 tcp outside/10.2.8.35 -> inside/10.1.140.137(13000)
 udp outside/10.2.8.25 -> inside/10.1.9.14(137)
 udp outside/10.2.8.25 -> inside/10.1.81.15(137)
 tcp outside/10.2.8.44 -> inside/10.1.140.137(13000)
 tcp outside/10.2.8.31 -> inside/10.1.140.149(13000)

Noticed the “permitted” strings?

2. Denied traffic:

cat   asa.log | grep denied | grep access-list |
sed -e 's/^.*denied//' -e 's/hit-cnt.*$//' |
sed -e 's/([0-9][0-9]*) ->/ ->/' | less

Result:

 tcp inside/10.1.140.159 -> outside/10.2.8.24(515)
 tcp inside/10.1.140.159 -> outside/10.2.8.24(515)
 tcp inside/10.3.241.116 -> outside/10.2.8.251(1541)
 tcp inside/10.3.241.116 -> outside/10.2.8.251(1547)
 tcp inside/10.1.140.159 -> outside/10.2.8.24(515)

3. The most popular permitted traffic:

cat   asa.log | grep permitted | grep access-list | 
sed -e 's/^.*permitted//' -e 's/hit-cnt.*$//' |
sed -e 's/([0-9][0-9]*) ->/ ->/' |
awk ' {conn[$0]++;} END { for ( i in conn ) print conn[i],"	",i;}' | sort +0nr | less

Result (the first column is the amount of corresponding log entries):

21170   tcp outside/10.2.8.40 -> inside/10.1.140.149(13000)
18023   tcp outside/10.2.8.34 -> inside/10.1.140.149(13000)
17981   tcp outside/10.2.8.31 -> inside/10.1.140.149(13000)
11034   tcp inside/10.1.140.251 -> outside/10.2.8.68(10001)
10652   tcp outside/10.2.8.43 -> inside/10.1.140.137(13000)
10628   tcp outside/10.2.8.44 -> inside/10.1.140.137(13000)
10484   tcp outside/10.2.8.47 -> inside/10.1.140.137(13000)
10437   tcp outside/10.2.8.23 -> inside/10.1.140.137(13000)
7618   tcp outside/10.2.8.25 -> inside/10.1.140.137(13000)
7550   tcp outside/10.2.8.27 -> inside/10.1.140.137(13000)
7515   tcp outside/10.2.8.49 -> inside/10.1.140.137(13000)
7496   tcp outside/10.2.8.29 -> inside/10.1.140.137(13000)
6826   tcp outside/10.2.8.30 -> inside/10.1.141.23(8080)
6011   tcp outside/10.2.8.35 -> inside/10.1.140.137(13000)
5896   tcp outside/10.2.8.40 -> inside/10.1.141.23(8080)
5809   tcp outside/10.2.8.30 -> inside/10.1.140.137(13000)

4. Modification for versions 8.2+:

cat asa.log | grep Deny | grep access-group | sed -e 's/^.*Deny//' -e 's/by.*$//' | sed -e 's/dst/ ->/' -e 's/src//' | less

You can use this method to generate a policy based on the current traffic.

Additional “greps” will allow you to filter for specific ports or IP-addresses.

Replace “permitted” with “denied” and you’ll get the “most popular denied traffic”.

New school subjects?

The basics of networking and socionics should be taught in schools nowadays. It’s unbelievable to see people struggling to set up a static IP-address, and people following advices how to (“make friends”|”become more authoritative in a work-group”|”avoid conflicts”|”build a happy family”|etc…) that might work only for a couple of psychological types and will completely destroy any relationships with some others.

Из сСмСйной ΠΆΠΈΠ·Π½ΠΈ…

– И Ρ‡Ρ‚ΠΎ? Π― зря ΠΌΠΎΠΊ, Ρ‡Ρ‚ΠΎ Π»ΠΈ?
– Π’Π΅ΠΏΠ΅Ρ€ΡŒ ΠΈΠ΄ΠΈ, зря сохни.

– Иногда Π»ΡƒΡ‡ΡˆΠ΅ ΠΏΡ€ΠΎΠΌΠΎΠ»Ρ‡Π°Ρ‚ΡŒ
– Π’ΠΎΡ‚ ΠΈ ΠΏΡ€ΠΎΠΌΠ°Π»ΠΊΠΈΠ²Π°ΠΉ.