Vive les backups de backups de backups

Bon, j’en ai mis un de trop dans le titre, mais j’exagere a peine.

J’ai eu une tres mauvaise experience lundi avec ma machine qui fait les backups. Le power supply est mort, et ca sent un peu le chauffe. Bon, j’ai un autre power supply qui traine, je fais l’echange et je demarre la machine. C’est la que je vois une petit fumee s’elever au dessus des disques durs. Outch! Effetivement, le board est fini avec un chip qui a fondu! (Comment est-ce possible avec d’aussi faibles voltages???) Est-ce que c’est le nouveau power supply qui a fait ca, ou est-ce l’ancien? Je n’en sais rien, mais bon je ne prends pas de chance et decide qu’il est temps (bien que premature d’un an a peu pres) de changer de machine.

J’espere que le second disque dur est correct car sur la machine en question, il y a le compte de ma douce moitie et de fiston en plus du disque dur de backups. Je me demande lequel est inutilisable. Si au moins un des deux a survecu, alors toutes les donnees sont disponibles…. Et bien NON! Les boards des DEUX disques durs ont boucane. Wow, quelle succession d’emmerdements!

Tout ca pour dire que j’ai perdu les donnees des comptes et les backups incrementaux (sans compter deux disques durs de 500G). Ca va mal. Heureusement, j’ai fait un backup de niveau zero au debut de janvier, alors on a perdu essentiellement les emails des deux derniers mois de ma douce moitie. Elle n’est pas heureuse de ca, mais elle ne se rend pas compte a quel point elle aurait pu tout perdre si ce n’etait de ma procedure un peu delirante de backups. Le delai de deux mois aurait ete plus grave si c’etait mon compte qui y avait passe 😉

Dans les faits, je suis content de mon systeme de backup. Pour bien des gens, ca aurait ete la perte de toutes leurs photos/travaux/souvenirs/videos/etc parce que peu de personnes font des copies de surete. De mon cote, j’ai:
1) Un backup fait sur une machine a tous les 30 minutes (incremental)
2) Un backup du site web a tous les 6 heures (incremental)
3) Un backup de niveau zero une fois au trois ou quatre mois environ avec une copie sur un disque externe que je garde a portee de main et une autre copie a l’exterieur de la maison.

La seule chose que je changerai dans ma procedure est de faire une copie plus frequemment des backups incrementaux sur un disque externe. Ceci m’aurait permis de perdre moins de donnees.

J’utilise des disques durs pour les backups parce que je me suis toujours dit qu’il serait possible d’utiliser un programme comme SpinRite par exemple pour recuperer des donnees meme si le media commencait a se deteriorer. Comparez ca a un DVD-R qui n’est plus lisible…. on est foutu. Mon experience me montre que meme un disque dur peut etre completement inutilisable sans que la maison passe au feu ou qu’on se fasse voler l’ordinateur. Ceci etant dit, je continue de penser que d’utiliser des disques dur est la solution optimale, A CONDITION d’avoir des backups de backups de backups.

Pour les curieux, ma nouvelle machine devrait me permettre de jouer aux derniers jeux sans probleme 😉

Tidal locking

Je croyais que le fait que la Lune ait une rotation synchrone etait un heureux hasard. Mais j’aurais du me douter que si c’etait le cas pour notre Lune, ca devait etre plutot banal comme situation. C’est en effet le cas grace au “Tidal locking” qui pousse les rotations de lunes a etre synchrones.

Tire de wikipedia.org: Synchronous rotation:

The Moon is in synchronous rotation about the Earth. In fact, most major moons in the solar system have synchronous rotation due to tidal locking.

Newborns’ Blood Used To Build Secret DNA Database

Newborns’ Blood Used To Build Secret DNA Database

“The Texas Department of State Health Services routinely collected blood samples from newborns to screen for a variety of health conditions, before throwing the samples out. But beginning in 2002, the DSHS contracted Texas A&M University to store blood samples for potential use in medical research. These accumulated at rate of 800,000 per year. The DSHS did not obtain permission from parents, who sued the DSHS, which settled in November 2009. Now the Tribune reveals that wasn’t the end of the matter. As it turns out, between 2003 and 2007, the DSHS also gave 800 anonymized blood samples to the Armed Forces DNA Identification Laboratory to help create a national mitochondrial DNA database. This came to light after repeated open records requests filed by the Tribune turned up documents detailing the mtDNA program. Apparently, these samples were part of a larger program to build a national, perhaps international, DNA database that could be used to track down missing persons and solve cold cases.”

Energy Is Not Conserved

Energy Is Not Conserved

The point is pretty simple: back when you thought energy was conserved, there was a reason why you thought that, namely time-translation invariance. A fancy way of saying “the background on which particles and forces evolve, as well as the dynamical rules governing their motions, are fixed, not changing with time.” But in general relativity that’s simply no longer true. Einstein tells us that space and time are dynamical, and in particular that they can evolve with time. When the space through which particles move is changing, the total energy of those particles is not conserved.

Key Letter By Descartes Found After 170 Years

Key Letter By Descartes Found After 170 Years

“[T]housands of treasured documents… vanished from the Institut de France in the mid-1800s, stolen by an Italian mathematician. Among them were 72 letters by René Descartes… Now one of those purloined letters has turned up at a small private college in eastern Pennsylvania… The letter, dated May 27, 1641, concerns the publication of Meditations on First Philosophy, a celebrated work whose use of reason and scientific methods helped to ignite a revolution in thought.”

Un commentaire rigolo sur slashdot:

> can we have the text please? (Preferably in a human language)

Sorry, it’s written in French.

On Crete, New Evidence of Very Ancient Mariners

On Crete, New Evidence of Very Ancient Mariners

Via: richarddawkins.net: On Crete, New Evidence of Very Ancient Mariners

That is the startling implication of discoveries made the last two summers on the Greek island of Crete. Stone tools found there, archaeologists say, are at least 130,000 years old, which is considered strong evidence for the earliest known seafaring in the Mediterranean and cause for rethinking the maritime capabilities of prehuman cultures.

Crete has been an island for more than five million years, meaning that the toolmakers must have arrived by boat. So this seems to push the history of Mediterranean voyaging back more than 100,000 years, specialists in Stone Age archaeology say. Previous artifact discoveries had shown people reaching Cyprus, a few other Greek islands and possibly Sardinia no earlier than 10,000 to 12,000 years ago.

Life-like evolution in a test tube

Life-like evolution in a test tube

Via: richarddawkins.net: Life-like evolution in a test tube

For the first time, scientists have synthesized RNA enzymes – ribonucleic acid enzymes also known as ribozymes – that can replicate themselves without the help of any proteins or other cellular components. What’s more, these simple nucleic acids can act as catalysts and continue the process indefinitely.

APOD: Mars and a Colorful Lunar Fog Bow

APOD: Mars and a Colorful Lunar Fog Bow

Explanation: Even from the top of a volcanic crater, this vista was unusual. For one reason, Mars was dazzlingly bright two weeks ago, when this picture was taken, as it was nearing its brightest time of the entire year. Mars, on the far upper left, is the brightest object in the above picture. The brightness of the red planet peaked last week near when Mars reached opposition, the time when Earth and Mars are closest together in their orbits. Arching across the lower part of the image is a rare lunar fog bow. Unlike a more commonly seen rainbow, which is created by sunlight reflected prismatically by falling rain, this fog bow was created by moonlight reflected by the small water drops that compose fog. Although most fog bows appear white, all of the colors of the rainbow were somehow visible here. The above image was taken from high atop Haleakala, a huge volcano in Hawaii, USA.