Monthly Archives: July 2009


Abandon hope all ye who enter here. That is the sign above the entrance to Dante’s Inferno and quite frankly it should also  be above the entrance to most Telecoms in Greece right now.

The market has been  turmoil, so much so that a number of small operators closed up shop and a number of medium to large ones are merging or are being acquired. We , the workers, all knew that this day would come, we just hoped it would be postponed indefinitely. Unfortunately the days of reckoning are  upon us, and that brings me to the topic of this blog entry, despair and depression.

When one sees the faces of co-workers one can only see anxiety an despair. The times are tough and a layoff can be disastrous for a family man or quite frankly for everyone. In these difficult and trying times my only consolation to my work force is the following simple mantra:

I do not know what is in store for us, what I know is that we have worked hard as team and built elegant systems and kept the shop going while others sat on their haunches bemoaning their fate. If you do not trust yourself and your abilities, if you doubt whether you will make it or not, stand back and recount your work. Trust your work and your efforts, it has been good and valuable and if things work out the way they are supposed to work in this life, the value of your toils will become apparent. Trust your work and count on that trust. Artifacts, which is what you artisans make, have a tendency to seek out their creators. Trust your cerebral children and they will lead the way back to you.

This little mantra has been quite effective to keep my team’s morale from sliding down the ravine of despair. That and a good stream of work therapy


Organic foods and cholesterol

To my wife’s insistent coaxing, married people will understand, I got myself a blood test for the various nasties that flow within all of us.  Much to my surprise I found out that my cholesterol went down from 260 to 220 within a year without major effort. What changed is that we have largely switched as a family to organic foods, mostly because of our daughter. We are trying to give her as healthy a kick start as we can, and since we all sit on the same table, we all eat the same food. Oh yes we do follow the Mediterranean diet since we live in the neighborhood, but I do not think that had any effect since we have been following it forever. I did not make any sacrifices, we still get the occasional pizza or gyro, occasional right that is once in a fortnight or so.

So any doctors out there willing to speculate on metabolisms going haywire because of chemicals?

Hello world!

Let’s see how wordpress pans out! I really want to move away from

Οδηγίες προς Ναυτιλευομένους Γονείς

Εχω μια ιδέα για μιά νέα υπηρεσία και θα ήθελα τη γνώμη κάποιων απο εσάς που θα θέλατε να συμμετάσχετε. Ως γνωστόν έχω βγάλει το rautor σαν open source. Αυτό όμως δεν διευκολύνει καθόλου ενα μή τεχνογνώστη γονέα να προστατεύσει και να παρακολουθήσει τα παιδιά του απο την κακή χρήση του Internet.

Σκέφτηκα λοιπόν, στήνει κάποιος με resources (χρήμα κυρίως) ενα server όπου ο rautor μπορεί να αποστέλλει και αποθηκεύει τα screenshots κ.λ.π. Στο τέλος κάθε μήνα ή όποτε επιλέγει ο εκάστοτε γονέας, μπορεί να του αποστέλλεται ένα CD όπου να είναι καταγεγραμμένη η εν λόγω χρήση μαζί με τον RautorViewer. Υπάρχουν διάφορα νομικά ζητήματα αλλά πιστεύω πως ξεπερνώνται.

Επιπροσθέτως έχω και άλλο ένα μικρό προγραμματάκι που προηγείται του opendns ενός ή δύο ετών. Το kidmon που μπορείτε να το βρείτε στο site μου, κλειδώνει τον υπολογιστή να χρησιμοποιεί ένα συγκεκριμένο proxy. Το proxy αυτό λοιπόν μπορεί να κάνει και φιλτράρισμα περιεχομένου ώστε να περιοριστεί τα downloads των κακόβουλων σελίδων.

Ιδέες / σχόλια ;

Προσοχή: ο rautor αυτή τη στιγμή έχει ήδη τη δυνατότητα session upload αλλά μόνο μέσω FTP που δέν είναι πρωτόκολλο ασφαλές για χρήση WAN. Αναπτύχθηκε για ενδοεταιρική χρήση όπου η πρόσβαση στο καλώδιο είναι περιορισμένη. Τη στιγμή που υπάρχει επικοινωνία μέσω WAN (adsl) η ασφάλεια παύει.

Mean Scores

MOS or Mean Opinion Score is the measure by which a VOIP call is categorized as good, bad, or all Greek to me, local pun intended. There are many good companies offering devices to measure this score and once upon a time they used to publish their algorithms too. I was budget strapped as always in this wonderful historic gutter I currently inhabit, so I went prowling the wires for an API or two.

I came across probably the most promising VOIP API ever , project pjsip. PJsip is extremely well documented and provides samples of working code too, and compatible with asterisk to boot. So I spent a fortnight toying with the sample apps and test coding and this and that and following diff booted itself to life.

So now one can make a test call against an Asterisk server, have the server playback some or any recorded message and at the end of this conversation you get various metrics and the MOS score. The exact mechanics of this approach I leave to the interested students. A nice way to see if the application calculates meaningful scores is to freeze it ( on unix via ctrl-Z). This will effectively create an artificial UDP packet loss in the conversation between the two end points. Restart the application again and watch what happens to the MOS score !

To give credit where credit is due, the following code is an adaptation of Telchemy’s algorithm which they used to have publicly available on their site.