Entries by Joerg Moellenkamp

I've learned in the last few weeks that a simple design decision can make your life much more problematic. At the moment there is some discussion around the next generation of the 737 and the A320. Both are cash-cows of their firms (787 two years late, 747-8i isn't really a blockbuster, A380 still problematic) but both system are aging designs. The 737 even more than the A320. At the moment they both think to put new engines on the planes instead of designing totally new aircrafts.

What's the design decision that could be problematic? It's the length of the landing gear. The 737 was designed in an age, when the jet engines of the aircraft were rather slim, but long designs. The original P&W JT8D has just a fan diameter of 1.25 meters. Thus it didn't needed such a large clearance between the the ground and the wings. At the time, the A320 was designed large turbofans with a large bypass ratio were normal, thus you needed more space between the wings and the ground. The A320's CFM56-5B1 has a fan diameter of 1.74m. At some time in the past the 737 was reengined, the fan got larger (but not as large at the A320 one) and nowadays you could joke that a 737 almost scrubs the ground with its engine. The 737 uses an CFM56-3B1 with 1.54 meters today.

Now there is another reengining imminent: For example there is some discussion around so called geared turbofans, where the turbine and the fans are coupled with a gear box allowing both to work at their most efficient speed.

The problem is that most new types of jet engines are substantially larger than the old ones.And there the design decision and the age of the design haunts you. You can't get the engine under the wings of an 737. The A320 has the room for it, as the landing gear is much longer. It was developed in a different time.

Even with the current engines this led to some design changes. When you look at an 737 and an A320 you will recognize that the 737 haven't a round inlet. It had to be done this way because they had to move equipment from the bottom of the engine to the left and right from the lowest most point.

However an P&W geared turbo fan with the same trust as an CFM56-3B1 has a fan diameter of 1.8 meters. The alternative CFM Leap-X is said to have almost the same diameter. I once read that the engine to ground distance is just 48 cm with the current CFM ... putting an engine with an 30 cm larger fan on it would cut it down to 15 cm. I'm not sure about the point if this is really sufficient

It pretty much looks like the 737 needs substantially longer legs. But a longer gear leads to structural changes to the fuselage, as you have to retract the gear into the fuselage. Perhaps they have even change the track width of the landing gears because of the center of gravity.

Why did i write about it - it's a good example i've learned in IT business, too: No matter how much headroom you design in your technical stuff, the moment of the end the headroom will reach you. And every design decision will haunt you at some point in time. And in the case you had planed for 2 generations ahead, someone will cut down your headroom And so you reach a time where you have really make big changes. So fight for every centimeter of headroom.

Reuters reports, that Russia's FAS has agreed to the Oracles acquisition of Sun:

Russia's Anti-monopoly regulator (FAS) said on Friday it has approved [...] takeover of Sun Microsystems JAVA.O by Oracle (ORCL.O) on condition that Oracle continues to develop Sun's MySQL database. "FAS has reviewed the application and ... has decided to approve the application," the regulator, said in a statement, [...]

There is a paragraph in Infoweeks recent "Global CIO: Why Oracle's Earnings Will Improve With Sun" article i can comply with wholeheartedly:

Few acquisitions sparked more ill-informed speculation than Oracle's takeover of Sun: from the angst of the EU's anticapitalists, to SAP's and Microsoft's delusional attacks on Larry Ellison's hardware strategy, to the UBS analyst who said Oracle will fire 14,000 Sun employees, to the Motley Fool blogger who said it's a bad deal because Oracle doesn't understand hardware (yes, he really said that).

Amen!

Der Hauptvortrag auf dem 11. HHOSUG-Meeting steht nunmehr fest. Heiko Stein wird einen Vortrag zum Thema Live Upgrade aus der Perspektive des nahezu täglichen Benutzers halten. Neben der Theorie wird der Vortrag auch Tricks und Verfahrensweisen im Umgang mit LU enthalten. Es verspricht interessant zu werden. Anmeldung via hhosug11@joerg.moellenkamp.org bzw. via XING.

Die Bremer Universität war meines Wissens mal dafür bekannt, im linken Spektrum noch einen Platz an der Wand einzunehmen. Das scheint sich irgendwie erledigt zu haben. Zumindestens wenn man sich einen Kommentar eines Bremer Sozialpädagogikprofessors in der FAZ durchliesst, über den Telepolis berichtet: "Das unwerte Hartz IV-Leben". Ich übernehme hier einfach mal das Zitat, das auch Telepolis bringt:

Während deutsche Frauen außerhalb von Hartz IV im Durchschnitt nur ein Kind haben und leistungsstarke Migrantinnen sich diesem Reproduktionsmuster nähern, vermehrt sich die vom Sozialstaat unterstützte Unterschicht stärker - mit allen Folgeproblemen. So sind in der Hartz-IV-Musterkommune Bremerhaven die Jungen in Sozialhilfe mit einem Anteil von rund 40 Prozent an der männlichen Jugend für mehr als 90 Prozent der Gewaltkriminalität verantwortlich. Solange die Regierung das Recht auf Kinder als Recht auf beliebig viel öffentlich zu finanzierenden Nachwuchs auslegt, werden Frauen der Unterschicht ihre Schwangerschaften als Kapital ansehen. Allein eine Reform hin zu einer Sozialnotversicherung mit einer Begrenzung der Auszahlungen auf fünf Jahre statt lebenslanger Alimentierung würde wirken - nicht anders als in Amerika.

Wie weit ist es bitteschön von diesem Sprachgebrauch, von dieser Forderung, bis zur chemischen Sterilisierung während des HartzIV-Bezuges. Vielen Dank, Herr Prof. Heinsohn, ich dachte, diese Zeiten hätten wir hinter uns.

Ansonsten fallen mir dazu zwei andere Paragraphen ein, als die von Telepolis genannten: §5 Absatz 3 "Kunst und Wissenschaft, Forschung und Lehre sind frei. Die Freiheit der Lehre entbindet nicht von der Treue zur Verfassung." und §20 Absatz 1 " Die Bundesrepublik Deutschland ist ein demokratischer und sozialer Bundesstaat." Das möge sich Herr Professor mal vor Augen halten.

Im übrigen: Wenn man schon mit diesen Begrifflichkeiten argumentieren möchte, könnte man zu einem wesentlich effektiveren Mittel kommen. Wenn das Problem die Bildungsferne des Milieus ist, dann könnte eine Ganztagsschule (somit eine Entfernung und Entfremdung des Kindes aus dem bildungsfernen Milieus) nebst individueller Förderung mehr bringen, als die Fortpflanzung des Bildungsschichten durch Aushungern zu unterbinden. Denn nichts anderes schlägt dieser Herr vor. Allerdings: Die Aktivierung des bildungsfernen Milieus und somit die effektive Ausnutzung des Humankapitals aus eigener Aufzucht würde zunächst einmal eine Investition bedeuteten. Bevor wir in Exzellenzzentren investieren (was sich so ausnimmt wie das Wegräumen von Eisbrocken auf dem Deck der Titanic), braucht unser Land erst mal eine Investition in die Grundlage.

Belohnt würden wir mit Fachkräften mit einer wesentlich höheren Bindung an unser Land. Jemand, der in Deutschland geboren ist, wird wahrscheinlich weniger Anfällig für ein Abwerben sein, wie jemand, der sein Heimatland schon mal verlassen hat, den Willen das Heimatland der Karriere wegen hinter sich zu lassen schon demonstriert ha.t Wenn man dann auch noch dazu kommen würde, das deutsche Bildungssystem durchlässiger zu machen, und so auch bildungsfernen Gruppen eine Chance zu geben, dann wäre uns weit mehr geholfen. Stattdessen holt man sich lieber die Eliten aus anderen Ländern, wohl in der Hoffnung, das diese zur Rente dann wieder in ihre Länder zurückkehren.

I get more more and more news about hard disks that yield checksum errors with ZFS. However even my RAID set of cheap hard disks didn't yielded any error so far, despite being significantly loaded by the Family Member Wide Area Network. I found this a little bit strange and asked a few people for location and cooling situation. One common denominator of other systems was that they used internal bays, but without any fans for the hard disk. My home server has an independent set of two 12cm fans for the harddisks. At the moment i just a assumption, but i think, that those low-end el-cheapo disks need significant cooling to work longer than just a while without errors, at least significantly more cooling than most people allow them to get. Perhaps you should consider this point for your home servers.

To get some additional data i want you to ask some question. In the case you use ZFS, did you experience any checksum errors while scrubbing? Do you have independent cooling for your hard disks?

Storing a marriage in a database can be really mind-bogling when you want to store every possible way to marry a significant other in a database: Gay marriage: the database engineering perspective. Excellent read.

It's just a single track i want to recommend today: It's Animal Collective's "My Girls" from their album "Merriweather Post Pavillion". I heard this track yesterday while watching a documentary about the free solo base jumper (climbing hills without ropes and doing a base jump instead of falling to death) Dean Potter. Somewhat strange music, but i like it ... especially the second half.

There is a neat trick in the case you have an serial adapter, but no terminal programm at your disposal, your mobile data plan don't allow a larger download. Well, just open a shell:

screen /dev/tty.<whatever>

At least for a Sun ILOM serial mgnt port it works right out of the box.

PS: Don't use the original MacOS X driver for Prolific based USB/Serial converters, the open-source variant is a much better alternative (implements BREAK, installer doesn't freeze) . You can download it from the sourceforge project page.

Once in a while Kris ask his reader who they are. This remembers me each time, to ask the same question in my blog. Kris asked this question yesterday. And of course this remembered me about asking my readers, so i want to ask the same questions: Who are you? Why are you reading c0t0d0s0.org? What do you like about this blog? What do you want to see improved? Which topics would you like to see in the next 12 months?

PS: Answers in english or german are welcome. Other languages would go through Google Translate, so don't be so astonished when i'm insulted by the stuff pouring out of the translator

Peter Judge of eweek visited one of the events taking place to welcome customers and partners of Sun and it looks like that he was a little bit astonished:

The most surprising thing about the event was the complacency. Many of the delegates suggested that this merger, billed as one of the most cataclysmic ever (in a good way or a bad way), might simply lead to business as usual, with the products and support coming from the usual partners and executives, and the roadmap continuing.

In my personal opinion, most customers in IT have a very laid-back view in perspective to our industry and especially in regard to the cat fights between the competitors in our industry. Neither they don't buy in to every nice image a market player tries to paint nor they believe in the images of doom the competitors try to paint about technologies, other companies or just ideas. And most of them take every media coverage with a really large grain of salt. Most customer have a simple approach: "Prove it". Thus i'm not really astonished about the comments in the coffee breaks. It's just the way the business goes in reality.

I've reported about the PSARC case a while ago, but now it's in the code: This putback introduced the fast reboot feature to SPARC. It's implemented a little bit differently at the moment, as it doesn't totally circumvents POST, but it shorten POST substantially by skipping parts of it.

Nur um sich schon mal den Tag im Kalender zu reservieren: Am 8.4.2009 findet von 19:00 bis 22:00 (man lernt ja ) das 11. HHOSUG-Meeting statt. Ich bin noch bei der Themenfindung, werde also noch nachreichen, welche Vorträge auf der Agenda stehen. Trotzdem könnt ihr euch via hhosug11@joerg.moellenkamp.org oder via XING für die Pizza anmelden.