I can take the despair. It’s the hope I can’t stand. ~ Brian Stimpson, Clockwise ‘
Huge respect for German chancellor Merkel
I, myself, actually would not be able to live with not having made this attempt — Angela Merkel.
De monarchie van’t land
Ik ben niet noodzakelijk voorstander van de of een monarchie. Maar wanneer het goed is, is het goed. De redacteurs van de VRT hebben zeker moeite gedaan een positief beeld te schetsen in Koppen. Maar zelfs moest ik moeite doen negatief te zijn, kan ik niets slechts vinden in het beeld dat men vandaag van koning Filip schetste. Ik ben tevreden dat iemand met zorg en zorgzaamheid met België en de Belgen bezig is.
De Fabeltjeskrant
https://www.youtube.com/watch?v=lIWy8taP1rE
Want daarin staat precies vermeld, hoe het met de dieren is gesteld.
nrl:maxCardinality one-to-many ontology changes
I added support for changing the nrl:maxCardinality property of an rdfs:Property from one to many. Earlier Martyn Russel reverted such an ontology change as this was a blocker for the Debian packaging by Michael Biebl.
We only support going from one to many. That’s because going from many to one would obviously imply data-loss (a string-list could work with CSV, but an int-list can’t be stored as CSV in a single-value int type – instead of trying to support nonsense I decided to just not do it at all).
More supported ontology changes can be found here.
Not sure if people care but this stuff was made while listening to Infected Mushroom.
Bescherm ons tegen afluisteren, luister zelf enkel binnen een wettelijk kader af
De overheid hoort onze burgers te beschermen tegen afluisteren, de overheid kan en mag zelf afluisteren maar kan en mag dit enkel binnen een wettelijk kader doen.
Allerlei zaken tonen aan dat overheden binnen de NAVO alliantie ons land aanvallen met digitale inbraken. Het baart me zorgen.
Technisch betekent dit voor mij dat ons land moet investeren in beveiliging van systemen. Hier hoort kennis en controle over hardware en software op diep niveau bij.
Ik hoop dat Pieter De Crem niet enkel in straaljagers maar ook in het beveiligen van ‘s lands computersystemen investeert.
Dat betekent voor mij kennis en controle op het niveau van de bootloader, de kernel en de hardware. De systemen van de overheid bevatten immers bijzonder veel gegevens van de burger. De systemen van het leger geven dan weer informatie en toegang tot apparatuur die de beveiliging en de vrede van het land garandeert.
Wat betreft de kernel moet een recruit het boek van Robert Love de dagen voor het sollicitatiegesprek doornemen. Hij of zij moet met het Internet als hulp een kernel module kunnen maken. Dat is een minimum.
Een goede technische test zou zijn om een eigen rootkit kernel module te schrijven gedurende de dagen dat het sollicitatiegesprek plaatsvindt (ja, dagen). Hierbij zouden enkele doelstellingen kunnen opgesteld worden: Bv. het verbergen van de .ko file op het filesysteem die eerder met insmod ingeladen werd, het kopiëren van alle uitgaande TCP/IP data naar een verborgen stuk hardware, en zo verder.
Dit laatste zonder veel van het geheugen van de host te verbruiken daar het verborgen stuk HW vermoedelijk trager zal zijn dan de normale netwerk interface (de eth0 t.o.v. bv. 3G). Een oplossing zou kunnen zijn te filteren gecombineerd met af en toe wat packet loss te veroorzaken door verborgen netif_stop_queue en netif_wake_queue calls op de normale netwerk interface te doen. Misschien heeft de recruit wel betere ideeën die moeilijk of niet gedetecteerd kunnen worden? Ik hoop het!
De recruit moet een manier voorzien (die niet vanzelfsprekend is) om commando’s te ontvangen (liefst eentje die moeilijk gedetecteerd kan worden). Misschien het gebruik maken van radio op zo’n manier dat het moeilijk te detecteren is? Ik ben benieuwd.
Hoe meer van dat soort doelstellingen gehaald worden, hoe geschikter de kandidaat.
Wat betreft userland moet een recruit gegeven een stuk code waar een typische bufferoverflow fout in zit die bufferoverflow herkennen. Maar gun uw recruit de tijd en een ontspannen sfeer want onder stress zien enkel de gelukzakken af en toe eens zoiets. Het reviewen van (goede) code is nl. iets dat vele jaren ervaring vraagt (slechte code is eenvoudiger, maar over de slechte code van de wereld, zoals dnsmasq, gaan de hedendaagse security problemen niet. Wel over bv. OpenSSL en Bash).
De daarop volgende vraag zou kunnen zijn om door middel van die bufferoverflow ingevoerde code uit te laten voeren. Dit mag met behulp van het Internet om alle antwoorden te vinden. Extra punten wanneer de uitgevoerde code met of zonder netcat de zaak op een TCP/IP poort available maakt.
De dienst zou bv. een socket server kunnen maken dat een bufferoverflow heeft op de buffer die meegegeven wordt met read(). Dat zou zelfs een junior C developer moeten herkennen.
Dit soort van testen zijn nodig omdat enkel zij die technisch weten (en kunnen implementeren) hoe na een inbraak zichzelf te verbergen, geschikt zijn om het land te verdedigen tegen de NSA en de GCHQ.
Ik ben er van overtuigd dat zij die dit kunnen een redelijk goed moreel compas hebben: Mensen met zo’n inzicht hebben capaciteiten. Zulke mensen hebben daardoor vaak ook een goed doordacht moreel compas. Zolang de overheid haar eigen moreel compas volgt, zijn deze mensen bereid hun kunnen voor de overheid in te zetten.
Meneer de kolonel van het leger moet wel beseffen dat de gemiddelde programmeur eigenlijk gewoon technologie wil doorgronden. Dat die technologie toevallig ook voor bommen gebruikt wordt is niet de schuld van de programmeurs. Dat de kolonel zijn communicatie-technologie vol fouten zit wil niet zeggen dat de programmeurs die deze vinden criminelen zijn. Kolonel meneer zou beter tot Thor bidden dat s’ lands programmeurs er eerder achter komen dan de echte vijand erachter komt.
Maar de wet staat boven de militair. Ze moet gevolgd worden. Ook door de inlichtingendiensten. Het is onze enige garantie op een vrije samenleving: ik wil niet werken of geholpen hebben aan een wereld waarin de burger door technologie vrijheden zoals privacy verliest.
Met vriendelijke groeten,
Philip. Programmeur.
Please remove me from planet-gnome
Please remove me from planet-gnome: I’m nothing but trouble.
I want to create a new era for GNOME. The last few years at GNOME have created only desperation.
You guys invested heavily in Woman outreach programs and it didn’t create any meaningful innovation
You invested in …, oh right, you only invested in woman outreach programs.
I’m sorry, I wanted to make a list. But there is none. You could have invested in gnome-shell?
But also gnome-shell is by now being rightfully replaced by MATE. After several years, gnome-shell just doesn’t work.
I always understood that I’m the underdog of GNOME: the guy who the group wants to hate. That’s ok for me. Having worked on the core component of Tracker, tracker-store, you all rely on my code anyway. Please do me a great favor and rid yourself of my code: make the Tracker for gnome-shell: system() calling grep and find in a textbox which appears only if you figured out that you need to press a button with a gear icon. Perhaps always store all of the user’s documents in a public cloud storage and let google.com solve it half an hour later? Given the direction GNOME-desktop is taking; it isn’t an insane suggestion.
I need to speak up. Last time I tried using GEdit I had to fallback to using Pluma Text Editor to get any stuff done.
The so-called GNOME desktop is in an unusable state.
PADI Rescue diver
For this one I worked really hard. Buddy breading, relaxing people in panic at 20 meters deep, keeping yourself cool. And that in Belgian waters (no visibility and freezing cold). We simulated it all. It was harder than most other things I did in my life.
Voorzien
Nu de rest van het land nog
RE: Scudraketten
Wanneer Isabel Albers iets schrijft ben ik aandachtig: wij moeten investeren in infrastructuur.
Dit creëert welvaart, distribueert efficiënt het geld en investeert in onze kinderen hun toekomst: iets wat nodig is; en waar we voor staan.
De besparingsinspanningen kunnen we beperken wat betreft investeringen in infrastructuur; we moeten ze des te meer doorvoeren wat betreft andere overheidsuitgaven.
Misschien moeten we bepaalde scudraketten lanceren? Een scudraket op de overheidsomvang zou geen slecht doen.
Een week mediastorm meemaken over hoe hard we snoeien in bepaalde overheidssectoren: laten we dat hard en ten gronde doen.
Laten we tegelijk investeren in de Belgische infrastructuur. Laten we veel investeren.
Rusland
De cultuur die heerst, leeft, ploert en zweet op het grondgebied van Rusland zal niet verdwijnen. Zelfs niet na een nucleaire aanval tenzij die echt verschrikkelijk wreedaardig is. En dan zou ik ons verdommen dat we dat gedaan hebben zoals ik hoor te doen. Wij, Europeanen, moeten daar mee leven zoals zij met ons moeten leven.
Let’s make things better
Matthew gets that developers need good equipment.
Glade, Scaffolding (DevStudio), Scintilla & GtkSourceView, Devhelp, gnome-build and Anjuta also got it earlier.
I think with GNOME’s focus on this and a bit less on woman outreach programs; this year we could make a difference.
Luckily our code is that good that it can be reused for what is relevant today.
It’s all about what we focus on.
Can we please now go back at making software?
ps. I’ve been diving in Croatia. Trogir. It was fantastic. I have some new reserves in my mental system.
ps. Although we’re very different I have a lot of respect for your point of view, Matthew.
Tracker supports volume management under a minimal environment
While Nemo Mobile OS doesn’t ship with udisks2 nor with the GLib/GIO GVfs2 modules that interact with it, we still wanted removable volume management working with the file indexer.
It means that types like GVolume and GVolumeMonitor in GLib’s GIO will fall back to GUnixVolume and GUnixVolumeMonitor using GUnixMount and GUnixMounts instead of using the more competent GVfs2 modules.
The GUnixMounts fallback uses the _PATH_MNTTAB, which generally points to /proc/mounts, to know what the mount points are.
Removable volumes usually aren’t configured in the /etc/fstab file, which would or could affect /proc/mounts, plus if you’d do it this way the UUID label can’t be known upfront (you don’t know which sdcard the user will insert). Tracker’s FS miner needs this label to uniquely identify a removable volume to know if a previously seen volume is returning.
If you look at gunixvolume.c’s g_unix_volume_get_identifier you’ll notice that it always returns NULL in case the UUID label isn’t set in the mtab file: the pure-Unix fall back implementations aren’t fit for non-typical desktop usage; it’s what udisks2 and GVfs2 normally provide for you. But we don’t have it on the Nemo Mobile OS.
The mount_add in miners/fs/tracker-storage.c luckily has an alternative that uses the mountpoint’s name (line ~592). We’ll use this facility to compensate for the lacking UUID.
Basically, we add the UUID of the device to the mountpoint’s directory name and Tracker’s existing volume management will generate a unique UUID using MD5 for each unique mountpoint directory. What follows is specific for Nemo Mobile and its systemd setup.
We added some udev rules to /etc/udev/rules.d/90-mount-sd.rules:
SUBSYSTEM=="block", KERNEL=="mmcblk1*", ACTION=="add", MODE="0660", TAG+="systemd",
ENV{SYSTEMD_WANTS}="mount-sd@%k.service", ENV{SYSTEMD_USER_WANTS}="tracker-miner-fs.service
tracker-store.service"
We added /etc/systemd/system/mount-sd@.service:
[Unit] Description=Handle sdcard After=init-done.service dev-%i.device BindsTo=dev-%i.device [Service] Type=oneshot RemainAfterExit=yes ExecStart=/usr/sbin/mount-sd.sh add %i ExecStop=/usr/sbin/mount-sd.sh remove %i
And we created mount-sd.sh:
if [ "$ACTION" = "add" ]; then
eval "$(/sbin/blkid -c /dev/null -o export /dev/$2)"
test -d $MNT/${UUID} || mkdir -p $MNT/${UUID}
chown $DEF_UID:$DEF_GID $MNT $MNT/${UUID}
touch $MNT/${UUID}
mount ${DEVNAME} $MNT/${UUID} -o $MOUNT_OPTS || /bin/rmdir $MNT/${UUID}
test -d $MNT/${UUID} && touch $MNT/${UUID}
else
DIR=$(mount | grep -w ${DEVNAME} | cut -d \ -f 3)
if [ -n "${DIR}" ] ; then
umount $DIR || umount -l $DIR
fi
fi
Now we just have to configure Tracker right:
gsettings set org.freedesktop.Tracker.Miner.Files index-removable-devices true
Let’s try that:
# Insert sdcard
[nemo@Jolla ~]$ mount | grep sdcard
/dev/mmcblk1 on /media/sdcard/F6D0-FC42 type vfat (rw,nosuid,nodev,noexec,...
[nemo@Jolla ~]$
[nemo@Jolla ~]$ touch /media/sdcard/F6D0-FC42/test.txt
[nemo@Jolla ~]$ tracker-sparql -q "select tracker:available(?s) nfo:fileName(?s) \
{ ?s nie:url 'file:///media/sdcard/F6D0-FC42/test.txt' }"
Results:
true, test.txt
# Take out the sdcard
[nemo@Jolla ~]$ mount | grep sdcard
[nemo@Jolla ~]$ tracker-sparql -q "select tracker:available(?s) nfo:fileName(?s) \
{ ?s nie:url 'file:///media/sdcard/F6D0-FC42/test.txt' }"
Results:
(null), test.txt
[nemo@Jolla ~]$
Abstractionitis
Realizing I’ll be wrong again in future, I think I’m finally cured of abstractionitis. Thanks to Miguel for the diagnose and especially Rob who continuously pointed me out that you can’t escape the responsibility of having to actually implement. Thanks guys.
FOSDEM presentation about Metadata Tracker
I will be doing a presentation about Tracker at FOSDEM this year.
Metadata Tracker is now being used not only on GNOME, the N900 and N9, but is also being used on the Jolla Phone. On top a software developer for several car brands, Pelagicore, claims to be using it with custom made ontologies; SerNet told us they are integrating Tracker for use as search engine backend for Apple OS X SMB clients and last year Tracker integration with Netatalk was done by NetAFP. Other hardware companies have approached the team about integrating the software with their products. In this presentation I’d like to highlight the difficulties those companies encountered and how the project deals with them, dependencies to get a minimal system up and running cleanly, recent things the upstream team is working on and I’d like to propose some future ideas.
Dnsmasq’s code quality
Had to adapt dnsmasq’s code today. My god, that tiny application has a shitty code quality. I now feel bad knowing that so many systems are depending on this stuff.
Mr. Dillon; smartphone innovation in Europe ought to be about people’s privacy
Dear Mark,
Your team and you yourself are working on the Jolla Phone. I’m sure that you guys are doing a great job and although I think you’ve been generating hype and vaporware until we can actually buy the damn thing, I entrust you with leading them.
As their leader you should, I would like to, allow them to provide us with all of the device’s source code and build environments of their projects so that we can have the exact same binaries. With exactly the same I mean that it should be possible to use MD5 checksums. I’m sure you know what that means and you and I know that your team knows how to provide geeks like me with this. I worked with some of them together during Nokia’s Harmattan and Fremantle and we both know that you can easily identify who can make this happen.
The reason why is simple: I want Europe to develop a secure phone similar to how, among other open source projects, the Linux kernel can be trusted. By peer review of the source code.
Kind regards,
A former Harmattan developer who worked on a component of the Nokia N9 that stores the vast majority of user’s privacy.
ps. I also think that you should reunite Europe’s finest software developers and secure the funds to make this workable. But that’s another discussion which I’m eager to help you with.
In agreement
Surprisingly I’m in agreement with what Richard has to say in this specific context.
Why do you need Tracker?
(Or why our project’s name wasn’t wrong after all)
First and foremost, because the Internet isn’t available everywhere all the times. To put it simple: 3G (and 4G) suck. The latency is a joke in even the most modern countries, even at the center of their capital cities. Reliable availability of The Internet simply doesn’t exist for most people. Not even after a decade of promises and billion dollar investments from advertising firms like Google. Balloons that bring The Internet everywhere? Yeah, sure.
I invite you to try a serious Google maps use-case in a Swiss tunnel. The kind of use-case the nineties Microsoft Automap Streets & Tips – like software easily managed for planning vacations and trips across Europe decades ago (without The Internet). Or how about reading the newspapers on the airplane? Technology of pre the year 1700 could do it. Today Google’s tablets & glasses can’t, because I have no reliable Internet (the flight-attendant will reliably give me a newspaper, though – go ahead, try it Sergey). And if Google installed 3G routers in those tunnels, airplanes, forests, all third world countries, seas and the truly remote areas of the planet , I could still come up with a lot more places. Everybody can. By the time the Googles of today are finished, we’ll all travel to Mars with latencies of up to an hour while Google’s data still only travels at the speed of light (that, or fix quantum entanglement to be workable and more importantly: scalable to billions of users).
It’s great that sometimes we can use Google maps, sure. But if I can’t rely on it always and everywhere, it means that in embedded: it doesn’t exist. I want my Boeing 747’s landing software to work (oh and when we land on Mars, too). Always. I want software to land us safely. Same for my car’s ABS, the subway and train’s breaking systems. I’ll probably be dead when those services don’t operate when I need them. During those moments I don’t care about Google fans and their Google HTML5 religion. Screw HTML5, JavaScript, WebSocket and 3G and thank you interrupt based real time kernels that open my airbag, stop the tram and land the airplane.
For the car industry it’s probably cheaper to provide a storage hardware upgrade when the car must be serviced, than it would be to sell your company’s soul to privacy invading Cloud hosting services. Because in future I would like you to provide Facebook-like services in my car, as reliable as my airbag works. Without the Internet being everywhere. I want you to deliver it to me when I’m visiting Mars. And my kids … who knows what they’ll want?!
Your embedded technology needs to provide graph data about the users’ activity to services that your business wants to share the data with. I’ll illustrate this with This-is-Possible-Today use cases:
– The fridge contains no more milk. While walking the street watching his smartphone, the user opens a recipe for a meal that requires milk. When the user is at the supermarket the technology that will in future be installed on supermarket shopping carts (or his glasses) needs to show the recipe, its ingredients and highlight the fact that the fridge doesn’t contain one of the required ingredients (milk, sugar, butter). And if the user allows this, advertise different brands of milk, sugar and butter based on who paid most plus his wife’s buying habits.
– Your kid talked with a school friend on Facebook about an amusement park (De Efteling! Phantasialand!). Your wife decides that because it’s good weather this weekend, the family should (will) go to an amusement park (yes, she’s the boss. And that’s fine: you own the car – don’t worry, she’ll drive the way back so you can have your weekend nap). So the entire family gets in the (your) car and you ask your son: what amusement park shall I drive to?! Your kid opens the infotainment system at the back seat of the car and sees what he has been interested in last few weeks. After privacy authorization (or not) you as the driver of the car sees the list on the dashboard infotainment system. You select it and the navigation software of the (your) car navigates to it. What a dad! Meanwhile your front passenger seat’s infotainment system goes to the ticket ordering website of the amusement park. What a mom! Advertising related to amusement parks and ticket vending is shown. Of course! Phantasialand!
That is why you need Tracker’s Nepomuk based storage with its SPARQL querying and updating capability.
It lets your embedded appliance do what Facebook does. But in a light way, isolated (or not) from the rest of the world. You decide what happens with the data and who receives it. Allowing you to provide a trust relationship with your customers and consumers. You are the industry providing those cars, fridges and TV sets.
As a BMW driver myself, I would stop buying BMW cars as soon as I learn that BMW sells my driving habits (or whatever) to Google or Facebook (or the NSA). Today I’d trust BMW to integrate those habits into the infotainment system of my next car. IF I can trust BMW. I think that in future it’ll be the difference between succeeding and failing as a industry.
With Tracker you get the use-cases and features. But it’s not for free: you must hire brains instead of paying Google or Facebook’s marketing boys. This comes as a surprise? It has always been that way in tech: Brains and hard work, innovate. Ask Wernher von Braun. They landed on the wrong planet, but in the sixties and seventies his rockets got us to the moon.
A car is a car. A fridge is a fridge. A TV set is a TV set. They shouldn’t be Google’s or Facebook’s data mining devices. Besides, why would you give the data away? Your appliances collected it, not theirs. Talk with your customers fairly and openly on how it can and how it can’t be used.
As managers at these industries it’s up to you to solve the crisis of social features vs. privacy mining.
Kind regards, from one of the guys who developed such technology for Nokia’s N9.
A use-case for SPARQL and Nepomuk
As I got contacted by two different companies last few days who both had questions about integrating Tracker into their device, I started thinking that perhaps I should illustrate what Tracker can already do today.
I’m going to make a demo for the public transportation industry in combination with contacts and places of interest. Tracker’s ontologies cross many domains, of course (this is just an example).
I agree that in principle what I’m showing here isn’t rocket science. You can do this with almost any database technology. What is interesting is that as soon as many domains start sharing the ontology and store their data in a shared way, interesting queries and use-cases are made possible.
So let’s first insert a place of interest: the Pizza Hut in Nossegem
tracker-sparql -uq "
INSERT { _:1 a nco:PostalAddress ; nco:country 'Belgium';
nco:streetAddress 'Weiveldlaan 259 Zaventem' ;
nco:postalcode '1930' .
_:2 a slo:Landmark; nie:title 'Pizza Hut Nossegem';
slo:location [ a slo:GeoLocation;
slo:latitude '50.869949'; slo:longitude '4.490477';
slo:postalAddress _:1 ];
slo:belongsToCategory slo:predefined-landmark-category-food-beverage }"
And let’s add some busstops:
tracker-sparql -uq "
INSERT { _:1 a nco:PostalAddress ; nco:country 'Belgium';
nco:streetAddress 'Leuvensesteenweg 544 Zaventem' ;
nco:postalcode '1930' .
_:2 a slo:Landmark; nie:title 'Busstop Sint-Martinusweg';
slo:location [ a slo:GeoLocation;
slo:latitude '50.87523'; slo:longitude '4.49426';
slo:postalAddress _:1 ];
slo:belongsToCategory slo:predefined-landmark-category-transport }"
tracker-sparql -uq "
INSERT { _:1 a nco:PostalAddress ; nco:country 'Belgium';
nco:streetAddress 'Leuvensesteenweg 550 Zaventem' ;
nco:postalcode '1930' .
_:2 a slo:Landmark; nie:title 'Busstop Hoge-Wei';
slo:location [ a slo:GeoLocation;
slo:latitude '50.875988'; slo:longitude '4.498208';
slo:postalAddress _:1 ];
slo:belongsToCategory slo:predefined-landmark-category-transport }"
tracker-sparql -uq "
INSERT { _:1 a nco:PostalAddress ; nco:country 'Belgium';
nco:streetAddress 'Guldensporenlei Turnhout' ;
nco:postalcode '2300' .
_:2 a slo:Landmark; nie:title 'Busstop Guldensporenlei';
slo:location [ a slo:GeoLocation;
slo:latitude '51.325463'; slo:longitude '4.938047';
slo:postalAddress _:1 ];
slo:belongsToCategory slo:predefined-landmark-category-transport }"
Let’s now get all the busstops nearby the Pizza Hut in Nossegem:
tracker-sparql -q " SELECT ?name ?lati ?long WHERE { ?p slo:belongsToCategory slo:predefined-landmark-category-food-beverage; slo:location [ slo:latitude ?plati; slo:longitude ?plong ] . ?b slo:belongsToCategory slo:predefined-landmark-category-transport ; slo:location [ slo:latitude ?lati; slo:longitude ?long ] ; nie:title ?name . FILTER (tracker:cartesian-distance (?lati, ?plati, ?long, ?plong) < 1000) }" Results: Busstop Sint-Martinusweg, 50.87523, 4.49426 Busstop Hoge-Wei, 50.875988, 4.498208
This of course was an example with only slo:Landmark. But that slo:location property can be placed on any nie:InformationElement. Meaning that for example a nco:PersonContact can also be involved in such a cartesian-distance query (which is of course just an example).
Let’s make an example use-case: We want contact details of friends (with publicized coordinates) who are nearby a slo:Landmark that is in a food and beverage landmark category, so that the messenger application can prepare a text message window where you’ll type that you want to get together to get lunch at the Pizza Hut.
Ok, so let’s add some nco:PersonContact to our SPARQL endpoint who are nearby the Pizza Hut:
tracker-sparql -uq "
INSERT { _:1 a nco:PersonContact ; nco:fullname 'John Carmack';
slo:location [ a slo:GeoLocation;
slo:latitude '51.325413'; slo:longitude '4.938037' ];
nco:hasEmailAddress [ a nco:EmailAddress;
nco:emailAddress 'john.carmack@somewhere.com'] }"
tracker-sparql -uq "
INSERT { _:1 a nco:PersonContact ; nco:fullname 'Greg Kroah-Hartman';
slo:location [ a slo:GeoLocation;
slo:latitude '51.325453'; slo:longitude '4.938027' ];
nco:hasEmailAddress [ a nco:EmailAddress;
nco:emailAddress 'greg.kroah@somewhere.com'] }"
And let’s add one person who isn’t nearby the Pizza Hut in Nossegem:
tracker-sparql -uq "
INSERT { _:1 a nco:PersonContact ; nco:fullname 'Jean Pierre';
slo:location [ a slo:GeoLocation;
slo:latitude '50.718091'; slo:longitude '4.880134' ];
nco:hasEmailAddress [ a nco:EmailAddress;
nco:emailAddress 'jean.pierre@somewhere.com'] }"
And now, the query:
tracker-sparql -q " SELECT ?name ?email ?lati ?long WHERE { ?p slo:belongsToCategory slo:predefined-landmark-category-food-beverage; slo:location [ slo:latitude ?plati; slo:longitude ?plong ] ; nie:title ?pname . ?b a nco:PersonContact; slo:location [ slo:latitude ?lati; slo:longitude ?long ] ; nco:fullname ?name ; nco:hasEmailAddress [ nco:emailAddress ?email ]. FILTER (tracker:cartesian-distance (?lati, ?plati, ?long, ?plong) < 10000) }" Results: Greg Kroah-Hartman, greg.kroah@somewhere.com, 50.874715, 4.49158 John Carmack, john.carmack@somewhere.com, 50.874715, 4.49154
These use-cases of course only illustrate the simplified location ontology in combination with the Nepomuk contacts ontology. There are many such domains in Nepomuk and when defining your own platform and/or a new domain on the desktop you can add (your own) ontologies. Mind that for the desktop you should preferably talk to Nepomuk first.
The strength of such a platform is also its weakness: if no information sources put their data into the SPARQL endpoint, no information sink can do queries that’ll yield meaningful results. You of course don’t have this problem in a contained environment where you define what does and what doesn’t get stored and where, like an embedded device.
A desktop like KDE or GNOME shouldn’t have this problem either, if only everybody would agree on the technology and share the ontologies. Which isn’t necessarily happening (fair point), although both KDE with Nepomuk-KDE and GNOME with Tracker share most of Nepomuk.
But indeed; if you don’t store anything in Tracker, it’s useless. That’s why Tracker comes with a file system miner and provides a framework for writing your own miners. The idea is that with time more and more applications will use Tracker, making it increasingly useful. Hopefully.