source            rc_bugs   all_bugs 
--------------------------+---------+----------
 wnpp                             0       3024
 installation-reports            10       2119
 apt                              4        682
 linux-2.6                        0        617
 aptitude                         0        576
 iceweasel                        3        490
 openssh                          1        417
 evolution                        0        362
 util-linux                       1        344
 dpkg                             1        343

Should Empathy just disappear on the desktop as things like presence applets or GNOME Shell take over parts of its function? Maybe, yes. In some ways its goal is just to bring Telepathy to end users and the desktop so that its worth other things integrating into Telepathy, but Telepathy allows us to do a lot better than a conventional IM client. Maemo and Sugar on the OLPC use Telepathy but totally integrates it into the device experience rather than having any single distinct IM client, and although Moblin uses Empathy currently it has its own presence chooser and people panel, and may go on to replace other parts of the user experience too. GNOME Shell looks set to move in this direction too and use Telepathy to integrate communications with the desktop workflow. Should Telepathy take care of talking to social networking sites such as Facebook, Twitter, etc? There s no hard and fast rule Telepathy only makes sense for real-time communications, so it s good for exposing and integrating the Facebook chat, but pretty lame for dealing with wall posts, event invitations and the like. Similarly on the N900, Telepathy is used for the parts of the cellular stack that overlap with real-time communications like calling and SMS, but there is no sense pushing unrelated stuff like configuration messages through it. For Twitter, the main question is whether you actually want tweets to appear in the same UI, logging and notification framework as other messages. Probably not anything but the 1-to-1 tweets, meaning something like Moblin s Mojito probably makes more sense for that. Later in the summit I took a look at Google Latitude APIs, which seem like something which Telepathy can expose via its contact location interface, but probably not usefully until we have support for metacontacts in the desktop. Can/will Telepathy support IAX2? It can, although we d have to do a local demultiplexer for the RTP streams involved in separate calls. It s not been a priority of ours so far, but we can help people get started (or Collabora can chat to people who have a commercial need for it). Similarly nobody has looked at implementing iChat-compatible calling because our primary interest lies with open protocols, but if people were interested we could give pointers its probably just SIP and RTP after you dig through a layer of obfuscation or two.

# tar -cf archive.tar list of files to include

# tar -xf archive.tar
# tar -xf archive.tar list of files

# tar -tf archive.tar

# tar -cf archive.tar directory
# gzip archive.tar

# gunzip archive.tar.gz
# tar -xf archive.tar

# tar -cf - directory   gzip > archive.tar.gz
# gunzip < archive.tar.gz   tar -xf -

# tar -czf archive.tar.gz directory
# tar -xzf archive.tar.gz

• http://en.wikipedia.org/wiki/Tar_(file_format)
• http://en.wikipedia.org/wiki/Bzip2
• http://en.wikipedia.org/wiki/Gzip

• AJP is a binary protocol, so is slightly quicker for both ends to deal with and uses slightly less overhead compared to HTTP, but this is minimal.
• AJP includes information like original host name, the remote host and the SSL connection. This means that ServletRequest.isSecure() works as expected, and that you know who is connecting to you and allows you to do some sort of virtualhosting in your code.

• defining a new merge driver somewhere in the git configuration (in .git/config or ~/.gitconfig for example):

  [merge "git-merge-dch"]
          name = debian/changelog merge driver
          driver = git-merge-dch -m %O %A %B %A
  

• defining the merge attribute for debian/changelog files either in .gitattributes in the repository itself or in .git/info/attributes:

  debian/changelog merge=git-merge-dch
  

• This great swath of an initiative was started by a very small yet vocal group of proponents whose assertions received little scrutiny.
• A solution tailored to the specific constraints of a portion of the audience has been put forth as the de facto solution for the entire audience.
• There is an ongoing assumption that the more complicated and costly solution must be superior to the simpler, existing solution.
• Cursory evaluation of a data set without rigorous attention to mitigating factors can lead to wildly inaccurate conclusions.
• The acceptability of a given solution is often tested against a narrow band of the overall criteria, and the solution is often optimized to pass that test.
• The likelihood that people will continue to choose the more expensive and complicated solution despite any data is high.

• The idea that what we re doing might be wrong unsettles some people, and their response is often ferocious and irrational defense of the status quo.
• Those who have a financial stake in the current mode of operation are less likely to be open to scrutinizing it.
• There will be some people whose primary objection to the scrutiny is that they didn t think of doing it first; these people will sometimes attack the person questioning things on the grounds that it s all a selfish, attention-mongering endeavor.
• There are some people who will also be open to examining why and how we re doing things; whether they conclude the same thing or not, they are a welcome presence among the larger mass of those who ardently refuse to entertain the possibility of a need to change.

package IkiWiki::FailReason;
use overload (
        '""'    => sub   $_[0][0]  ,
        '0+'    => sub   0  ,
        '!'     => sub   bless $_[0], 'IkiWiki::SuccessReason' ,
        '&'     => sub   $_[0]->merge_influences($_[1]); $_[0]  ,
        ' '     => sub   $_[1]->merge_influences($_[0]); $_[1]  ,
        fallback => 1,
);
package IkiWiki::SuccessReason;
use overload (
        '""'    => sub   $_[0][0]  ,
        '0+'    => sub   1  ,
        '!'     => sub   bless $_[0], 'IkiWiki::FailReason' ,
        '&'     => sub   $_[1]->merge_influences($_[0]); $_[1]  ,
        ' '     => sub   $_[0]->merge_influences($_[1]); $_[0]  ,
        fallback => 1,
);

(match_glob("index")   match_backlink("index")) & match_created_after("oldpage")

#!/bin/sh
cat >s1.h <<EOF
extern void test(int *);
#define DO(x) test(x)
EOF
cat >libs1.c <<EOF
#include <stdio.h>
#include "s1.h"
void test(int *a)  
	printf("%d\n", *a);
 
EOF
cat >libs1.map <<EOF
S_1  
 global:
  test;
 ;
EOF
cat >s2.h <<EOF
extern void test(int);
#define DO(x) test(*x)
EOF
cat >libs2.c <<EOF
#include <stdio.h>
#include "s2.h"
void test(int a)  
	printf("%d\n", a);
 
EOF
cat >libs2.map <<EOF
S_2  
 global:
  test;
 ;
EOF
cat >a.h <<EOF
void a(void);
EOF
cat >liba.c <<EOF
#include "s.h"
#include "a.h"
void a(void)  
	int b = 4;
	DO(&b);
 
EOF
cat > test.c <<EOF
#include "a.h"
#include "s.h"
int main()  
	int b = 3;
	DO(&b);
	a();
	return 0;
 
EOF
rm -f liba.so libs.so* test s.h
if test $# -le 0   test "x$1" != "xboth" ; then
gcc -Wall -O2 -shared -o libs.so.1 -Wl,-soname,libs.so.1 libs1.c
else
gcc -Wall -O2 -shared -o libs.so.1 -Wl,-soname,libs.so.1 -Wl,-version-script libs1.map libs1.c
fi
if test $# -le 0 ; then
gcc -Wall -O2 -shared -o libs.so.2 -Wl,-soname,libs.so.2 libs2.c
else
gcc -Wall -O2 -shared -o libs.so.2 -Wl,-soname,libs.so.2 -Wl,-version-script libs2.map libs2.c
fi
ln -s libs.so.1 libs.so
ln -s s1.h s.h
gcc -Wall -O2 -shared -o liba.so -Wl,-soname,liba.so liba.c -L. -ls
gcc -Wall -O2 test.c -L. -ls -la -o test
rm libs.so s.h
ln -s libs.so.2 libs.so
ln -s s2.h s.h
gcc -Wall -O2 -shared -o liba.so -Wl,-soname,liba.so liba.c -L. -ls
LD_LIBRARY_PATH=. ./test

// -*- mode: C++; c-indent-level: 4; c-basic-offset: 4;  tab-width: 8; -*-
//
// Another simple example inspired by an r-devel mail by Abhijit Bera
//
// Copyright (C) 2009 Dirk Eddelbuettel and GPL'ed
#include "RInside.h"                    // for the embedded R via RInside
#include "Rcpp.h"                       // for the R / Cpp interface used for transfer
#include <iomanip>
int main(int argc, char *argv[])  
    try  
        RInside R(argc, argv);          // create an embedded R instance
        SEXP ans;
        std::string txt = "suppressMessages(library(fPortfolio))";
        if (R.parseEvalQ(txt))          // load library, no return value
            throw std::runtime_error("R cannot evaluate '" + txt + "'");
        txt = "lppData <- 100 * LPP2005.RET[, 1:6]; "
	  "ewSpec <- portfolioSpec(); "
	  "nAssets <- ncol(lppData); ";
        if (R.parseEval(txt, ans))      // prepare problem
            throw std::runtime_error("R cannot evaluate '" + txt + "'");
	const double dvec[6] =   0.1, 0.1, 0.1, 0.1, 0.3, 0.3  ; // choose any weights you want
	const std::vector<double> w(dvec, &dvec[6]);
	R.assign( w, "weightsvec");	// assign STL vector to R's 'weightsvec' variable
	txt = "setWeights(ewSpec) <- weightsvec";
        if (R.parseEvalQ(txt))		// evaluate assignment
            throw std::runtime_error("R cannot evaluate '" + txt + "'");
	txt = "ewPortfolio <- feasiblePortfolio(data = lppData, spec = ewSpec, constraints = \"LongOnly\"); "
	  "print(ewPortfolio); "
	  "vec <- getCovRiskBudgets(ewPortfolio@portfolio)";
        if (R.parseEval(txt, ans))      // assign covRiskBudget weights to ans
            throw std::runtime_error("R cannot evaluate '" + txt + "'");
	RcppVector<double> V(ans);      // convert SEXP variable to an RcppMatrix
	R.parseEval("names(vec)", ans);	// assign columns names to ans
	RcppStringVector names(ans);
	for (int i=0; i<names.size(); i++)  
	  std::cout << std::setw(16) << names(i) << "\t"
		    << std::setw(11) << V(i) << "\n";
         
      catch(std::exception& ex)  
        std::cerr << "Exception caught: " << ex.what() << std::endl;
      catch(...)  
        std::cerr << "Unknown exception caught" << std::endl;
     
    exit(0);
 

1. PostgreSQL (MySQL does not provide sufficient geospacial features) I will be using Postgres 8.4.1; please adjust your paths for your version and/or distributor.
2. PostGIS spacial database extensions I will be using version 1.4.0.
3. Django I will be using version 1.1. This version includes the GeoDjango framework.
4. GEOS geometry engine I will be using version 3.0.0 from the libgeos-c1 package in Debian unstable.

$ django-admin startproject ukpostcodes
$ cd ukpostcodes
$ ./manage.py startapp postcodes

$ sudo -u postgres createlang plpgsql -d <databasename>
$ sudo -u postgres psql <databasename> -f /usr/share/postgresql/8.4/contrib/postgis.sql
$ sudo -u postgres psql <databasename> -f /usr/share/postgresql/8.4/contrib/spatial_ref_sys.sql

from django.contrib.gis.db import models
class Postcode(models.Model):
    name = models.CharField(max_length=8, db_index=True)
    location = models.PointField()
    objects = models.GeoManager()

$ ./manage syncdb

$ mkdir -p postcodes/management/commands
$ touch postcodes/management/commands/__init__.py
$ touch postcodes/management/__init__.py

import sys
import csv
from django.contrib.gis.geos import Point
from django.core.management.base import BaseCommand
from postcodes.models import Postcode
class Command(BaseCommand):
    def handle(self, \*args, \*\*options):
        Postcode.objects.all().delete()
        count = 0
        for row in csv.reader(sys.stdin):
            try:
                name = row[0].upper().strip().replace('  ', ' ')
                location = Point(map(float, row[13:15]))
            except ValueError:
                print "I: skipping %r" % row
                continue
            Postcode.objects.create(name=name, location=location)
            count += 1
            if count % 10000 == 0:
                print "Imported %d" % count

$ bunzip2 /path/to/uk-post-codes-2009.bz2   ./manage.py import_postcodes

>>> from postcodes.models import Postcode
>>> palace = Postcode.objects.get(name='SW1A 1AA')
>>> palace
<Postcode: SW1A 1AA>

>>> from django.contrib.gis.measure import Distance
>>> area = (palace.location, Distance(mi=1))
>>> Postcode.objects.filter(location__distance_lte=area)
[<Postcode: SE1 7BF>, <Postcode: SE1 7SG>, <Postcode: SE1 7JA>, <Postcode: SE1 7PB>,
 <Postcode: SE1 7PD>, <Postcode: SW1A 1DW>, <Postcode: SW1A 1EA>, <Postcode: SW1A 1EE>,
 <Postcode: SW1A 1EF>, <Postcode: SW1A 1EG>, '...(remaining elements truncated)...']
>>> Postcode.objects.filter(location__distance_lte=area)
7024

>>> Postcode.objects.distance(palace.location).order_by('distance')[:4]
[<Postcode: SW1A 1AA>, <Postcode: SW1E 6JP>, <Postcode: SW1E 6LA>, <Postcode: SW1E 6WG>]

class PizzaJoint(models.Model):
    name = models.CharField(max_length=200)
    postcode = models.ForeignKey(Postcode)
    objects = models.GeoManager()
    def __unicode__(self):
         return self.name

>>> def add_pizza_joint(name, loc):
...     code = Postcode.objects.get(name=loc)
...     PizzaJoint.objects.create(name=name, postcode=code)
...
>>> add_pizza_joint('Pizza Hut', 'SW1E 6SQ')
>>> add_pizza_joint('Pizza Express', 'SW1E 5NA')
>>> add_pizza_joint('Pizza On The Park', 'SW1X 7LY')

>>> PizzaJoint.objects.filter(postcode=palace)
[]

>>> PizzaJoint.objects.distance(palace.location,
            field_name='postcode__location').order_by('distance')
[<PizzaJoint: Pizza Hut>, <PizzaJoint: Pizza Express>, <PizzaJoint: Pizza On The Park>]

>>> for x in PizzaJoint.objects.distance(palace.location,
                     field_name='postcode__location').order_by('distance'):
...    print "%s (%d metres away)" % (x, x.distance.m)
...
Pizza Hut (499 metres away)
Pizza Express (509 metres away)
Pizza On The Park (902 metres away)

• squid - The caching proxy server.
• tor - The onion router.
• privoxy - The filtering cache.

• I load my start page in one tab: http://www.steve.org.uk/start/
• I click to open the following URL in another tab: http://www.perlmonks.org/?node=Newest Nodes.
• The request gets sent to http://steve.org.uk/?node=...

#python
if len(a) > 0:
        v = a[0]
        a = a[1:]
else:
        v = None

#ruby
v = a.empty? ? a.shift : nil

#ruby
if ! a.empty?
    v = a.shift
else
    v = nil
end

#ruby
v = if ! a.empty?
    a.shift
else
    nil
end

[1,2,3].inject(0)    sum, value  sum + value  

class Array
    def sum
        self.inject(0)  sum, value  sum + value 
    end
end

• I was installing Debian on a HP notebook intended for someone else. As always, almost everything worked out of the box, except sound, which kept hanging and crashing. I had to search for quite a while, before I found an ALSA workaround which was needed for this card (addition of an enable_msi option to the ALSA driver options). Being a good Debian citizen, I decided to file an installation-reports bug commending the Debian installer team (Christian Perrier has responded to quite a few of my reports; kudos to him), and letting them know of the ALSA bug.
• Christian Perrier thanked me for the report, and reassigned the bug to the alsa-driver package for further probing.
• Elimar Riesebieter promptly responded, and he tagged my bug as "wontfix". He told me how to get the workaround done properly, and pointed me to some documentation.
• I thanked him for his directions, but ranted that it upset me that the Debian ALSA maintainers didn't allow for the possibility of per card workarounds. I claimed that "Joe Users" won't care to read cryptic documents explaining the intricacies of snd-hda-intel, and they'll just install Debian Squeeze, and say "Debian didn't play my audio.", thus resulting in negative publicity. It was a rant, but I firmly believed that it wasn't unreasonable.
• Elimar patiently pointed out that it was not technically feasible for the ALSA maintainers to maintain a quirk-workaround method for every weird sound card they might come across. Moreover, he refused to take responsibility for a flaw which was actually in the chipset and not in the ALSA drivers. That sounded reasonable to me.
• However, Elimar was kind enough to forward this request to the ALSA developers' list, and ask them the right way to work around the problems posed by problematic sound cards.
• Takeshi Iwai and Daniel Chen promptly responded with proper instructions on how to work around the error. They said that it was ALSA's responsibility to handle these workarounds, so a patch should be provided to ALSA upstream. Moreover, Daniel Chen even produced the patch to handle this quirk.
• The patch is pushed upstream, and Elimar has added it to the Debian version, and has requested an upload, which should happen soon.