Oddio, c’è stato il linux day, dove si è disputata la lotta tra gli utilizzatori di Mandriva e noi, Ubuntuniani…

Sono stato eletto rappresentante d’istituto,e qui la cosa si fa interessante :P

Per il resto,ho imparato a ricompilarmi il kernel, anche se continuo ad avere dei problemi con l’utilizzo dell’initrd,anzi,con il non utilizzo! Magari farò un paio di post nel forum di ubuntu.it…!

Per il resto son qua che continuo a formattare tra win e linux a nastro, piu avanza il tempo piu mi rendo conto che nn è possibile staccarsi da questo merdoso mondo di windows! non è possibile cazzo =(

Facendo parte pure io di questo club, non posso far altro che farvi vedere ciò che ho trovato :D

Ah, sono in inglese, ma se sai programmare sicuramente dovrai conoscere l’inglese =D

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Their rumpled clothes, their unwashed and unshaven faces, and their uncombed hair all testify that they are oblivious to their bodies and to the world in which they move. These are computer bums, compulsive programmers. (Joseph Weizenbaum 1976)

Anyone who has attended a USENIX conference in a fancy hotel can tell you that a sentence like “You’re one of those computer people, aren’t you?” is roughly equivalent to “Look, another amazingly mobile form of slime mold!” in the mouth of a hotel cocktail waitress. (Elizabeth Zwicky)

Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning. (Rich Cook)

The most likely way for the world to be destroyed, most experts agree, is by accident. That’s where we come in; we’re computer professionals. We cause accidents. (Nathaniel Borenstein)

No delusion is greater than the notion that method of industry can make up for lack of mother-wit, either in science or practical life. (Thomas Huxley)

He who joyfully marches to music in rank and file has already earned my contempt. He has been given a large brain by mistake, since for him the spinal cord would suffice. (Albert Einstein)

Those people who think they know everything are a great annoyance to those of us who do. (Isaac Asimov)

There is a difference between eating a varied diet and chowing down on a cup of lard and sugar once a day. Programmers know this instinctively: they balance their daily menu among the four major food groups: caffeine, sugar, grease, and salt. (John Walker)

Let’s face the obvious: yesterday we were nerds, today we’re the cognitive elite. Let’s conquer. (Chester G Edwards)

What we do is never understood, but only praised and blamed. (Friedrich Nietzsche)

Be nice to nerds. Chances are you’ll end up working for one. (Bill Gates)

I cannot agree with those who rank modesty among the virtues. To the logician all things should be seen exactly as they are, and to underestimate one’s self is as much a departure from truth as to exaggerate one’s own powers. (“Sherlock Holmes”)

The trouble with the world is that the stupid are cocksure and the intelligent full of doubt. (Bertrand Russell)

The best way to prepare [to be a programmer] is to write programs, and to study great programs that other people have written. In my case, I went to the garbage cans at the Computer Science Center and fished out listings of their operating system. (Bill Gates)

You can get into a habit of thought in which you enjoy making fun of all those other people who don’t see things as clearly as you do. We have to guard carefully against it. (Carl Sagan)

Sometimes the best engineers come in bodies that can’t talk. (Nolan Bushnell)

To many managers, getting rid of the arrogant, undisciplined, over-paid, technology-obsessed, improperly-dressed etc. programmers would appear to be a significant added benefit. (Bjarne Stroustrup)

Mostly, when you see programmers, they aren’t doing anything. One of the attractive things about programmers is that you cannot tell whether or not they are working simply by looking at them. Very often they’re sitting there seemingly drinking coffee and gossiping, or just staring into space. What the programmer is trying to do is get a handle on all the individual and unrelated ideas that are scampering around in his head. (Charles M Strauss)

Optimism is an occupational hazard of programming: feedback is the treament. (Kent Beck)

I think it is inevitable that people program poorly. Training will not substantially help matters. We have to learn to live with it. (Alan Perlis)

Perhaps when a man has special knowledge and special powers like my own, it rather encourages him to seek a complex explanation when a simpler one is at hand. (“Sherlock Holmes”)

Beware of programmers who carry screwdrivers. (Leonard Brandwein)

The only thing more frightening than a programmer with a screwdriver or a hardware engineer with a program is a user with a pair of wire cutters and the root password. (Elizabeth Zwicky)

Insanity is often the logic of an accurate mind over-taxed. (Oliver Wendell Holmes)

The world is a tragedy to those who feel, but a comedy to those who think. (Horace Walpole)

The computer programmer is a creator of universes for which he alone is responsible. Universes of virtually unlimited complexity can be created in the form of computer programs. (Joseph Weizenbaum)

Suffusing [the technology] culture is the belief among programmers and engineers that they’re working on the Next Big Thing — projects that change the world, not just deliver a more absorbent diaper or crunchier breakfast cereal. (Joseph Menn)

Being a social outcast helps you stay concentrated on the really important things, like thinking and hacking. (Eric Raymond)

We shall do a much better programming job, provided we approach the task with a full appreciation of its tremendous difficulty, provided that we respect the intrinsic limitations of the human mind and approach the task as very humble programmers. (Alan Turing)

People that think logically are a nice contrast to the real world. (Matt Biershbach)

The trouble with programmers is that you can never tell what a programmer is doing until it’s too late. (Seymour Cray)

Fast, fat computers breed slow, lazy programmers. (Robert Hummel)

That’s what’s cool about working with computers. They don’t argue, they remember everything and they don’t drink all your beer. (Paul Leary)

Controlling complexity is the essence of computer programming. (Brian Kernigan)

For a long time it puzzled me how something so expensive, so leading edge, could be so useless, and then it occurred to me that a computer is a stupid machine with the ability to do incredibly smart things, while computer programmers are smart people with the ability to do incredibly stupid things. They are, in short, a perfect match. (Bill Bryson)

That tendency to err that programmers have been noticed to share with other human beings has often been treated as though it were an awkwardness attendant upon programming’s adolescence, which like acne would disappear with the craft’s coming of age. It has proved otherwise. (Mark Halpern)

Computer geek: an asocial, malodorous, pasty-faced monomaniac with all the personality of a cheese-grater. (Jargon Files)

Long hair minimizes the need for barbers; socks can be done without; one leather jacket solves the coat problem for many years; suspenders are superfluous. (Albert Einstein)

If your project doesn’t work, look for the part that you didn’t think was important. (Arthur Bloch)

For the time being, programming is a consumer job, assembly line coding is the norm, and what little exciting stuff is being performed is not going to make it compared to the mass-marketed cräp sold by those who think they can surf on the previous half-century’s worth of inventions forever. (Eric Naggum)

A great lathe operator commands several times the wage of an average lathe operator, but a great writer of software code is worth 10,000 times the price of an average software writer. (Bill Gates)

The principle objective of software testing is to give confidence in the software. (P D Coward)

In 1971 when I joined the staff of the MIT Artificial Intelligence lab, all of us who helped develop the operating system software, we called ourselves hackers. (Richard Stallman)

Burn-out in a developer is the death of the artistic self, a perverse maturation, a shrinking with age, a withering with experience. (Jim McCarthy)

Programming is like sex, one mistake and you have to support it for the rest of your life. (Michael Sinz)

Lovers of problem solving, they are apt to play chess at lunch or doodle in algebra over cocktails, speak an esoteric language that some suspect is just their way of mystifying outsiders. Deeply concerned about logic and sensitive to its breakdown in everyday life, they often annoy friends by asking them to rephrase their questions more logically. (Time Magazine in 1965)

A mathematician is a machine for turning coffee into theorems. (Paul Erdös)

Applicants must also have extensive knowledge of UNIX, although they should have sufficiently good programming taste to not consider this an achievement. (MIT job advertisement)

I just hate to be pushed around by some fücking machine. (Ken Thompson)

The programmer, like the poet, works only slightly removed from pure thought-stuff. He builds his castles in the air, from air, creating by exertion of the imagination. Few media of creation are so flexible, so easy to polish and rework, so readily capable of realizing grand conceptual structures. (Frederick P Brooks Jr)

Poor management can increase software costs more rapidly than any other factor. (Barry Boehm)

A programmer is a person who passes as an exacting expert on the basis of being able to turn out, after innumerable punching, an infinite series of incomprehensive answers calculated with micrometric precisions from vague assumptions based on debatable figures taken from inconclusive documents and carried out on instruments of problematical accuracy by persons of dubious reliability and questionable mentality for the avowed purpose of annoying and confounding a hopelessly defenseless department that was unfortunate enough to ask for the information in the first place. (IEEE Grid newsmagazine)

Eggheads unite! You have nothing to lose but your yolks. (Adlai Stevenson)

Computer science education cannot make anybody an expert programmer any more than studying brushes and pigment can make somebody an expert painter. (Eric Raymond)

A plumber has around eight years training in the US. That’s to fix my goddamn toilet. Yet, how much training do you have to do to be allowed to build software for a plane carrying hundreds of people? (James Coplien)

An organisation that treats its programmers as morons will soon have programmers that are willing and able to act like morons only. (Bjarne Stroustrup)

You needed a cool name to put on a T-shirt, and you needed a T-shirt to give to people. It was part of getting people excited enough to work 70 hours a week. (Erich Ringewald of Apple)

Programmers are like artists. Writing software that just gets put away feels like intellectual masturbation. (Bruce Perens)

A hacker on a roll may be able to produce, in a period of a few months, something that a small development group (say, 7-8 people) would have a hard time getting together over a year. IBM used to report that certain programmers might be as much as 100 times as productive as other workers, or more. (Peter Seebach)

Microsoft’s only factory asset is the human imagination. (Bill Gates)

Despite their reputa­tion for thick-headedness or stubbornness, it is important for technicians to see themselves as superior people who can easily adapt to change. (Taiichi Ohno)

The programmer, who needs clarity, who must talk all day to a machine that demands declarations, hunkers down into a low-grade annoyance. It is here that the stereotype of the programmer, sitting in a dim room, growling from behind Coke cans, has its origins. The disorder of the desk, the floor; the yellow Post-It notes everywhere; the whiteboards covered with scrawl: all this is the outward manifestation of the messiness of human thought. The messiness cannot go into the program; it piles up around the programmer. (Ellen Ullman)

See, you not only have to be a good coder to create a system like Linux, you have to be a sneaky bastard, too. (Linus Torvalds)

Pessimists, we’re told, look at a glass containing 50% air and 50% water and see it as half empty. Optimists, in contrast, see it as half full. Engineers, of course, understand the glass is twice as big as it needs to be. (Bob Lewis)

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Cisco CCNA

In sintesi la cisco (Famosa marca di router,switch, o comunque hardware di rete) mette a disposizione questi corsi che “formano” noi giovani come futuri ripara-reti marchiati cisco!! Il corso è composto da 4 semestri, in sostanza in 4 anni di studio (neanche troppo intenso) si può riuscire ad ottenere questa certificazione (a mio parere sicuramente utile).

In ogni caso, incollo un pò di soluzioni del quinto esame:

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CISCO CCNA EXAM 5 EXPLORATION

Refer to the exhibit. The network that is shown is running RIPv1. The 192.168.10.0/24 network was recently added and will only contain end users. What command or set of commands should be entered on Router1 to prevent RIPv1 updates from being sent to the end user devices on the new network while still allowing this new network to be advertised to other routers?
Router1(config-router)# no network 192.168.10.0

The following line was displayed in the output of the show ip route command.
R 192.168.3.0/24 [120/3] via 192.168.2.2, 00:00:30, Serial0/0
What is the value of the routing metric?
3

Which of the following is considered a limitation of RIP v1?
RIP v1 does not send subnet mask information in its updates.

Refer to the exhibit. The Ethernet interface on Router2 goes down and the administrator notices that the route is still in the Router1 routing table. How much longer will Router1 keep the down network in its routing table before marking it as possibly down?
155 seconds

Refer to the exhibit. Router1 is running RIPv1. What command was entered into Router1 to configure the gateway of last resort?
ip route 0.0.0.0 0.0.0.0 S0/0/1

What are three characteristics of the RIPv1 routing protocol? (Choose three.)
uses hop count as a metric
considers a metric of 16 as infinity
calculates metrics using the Bellman Ford algorithm

Which of the following would be the correct command sequence to enable RIP on Router B for all connected networks?
RouterB(config)# router rip
RouterB(config-router)# network 198.16.4.0
RouterB(config-router)# network 210.36.7.0
RouterB(config-router)# network 220.17.29.0

What is the default update period in seconds for the RIP routing protocol?
30

Refer to the exhibit. What can be concluded from the routing table output of router B?
The default-information originate command has been entered on A.

Refer to the exhibit. A network consists of multiple routers. What can be verified when the show ip protocols command is issued on one of the routers in the network?
routing protocol configuration in use for IP on this router

Refer to the exhibit. All routers are configured with valid interface addresses in the indicated networks and are running RIPv1. The network is converged. Which routes are present in the routing tables?
All routers have all /30 routes. Routers A and E also have some of the /24 routes in their routing table.

Which two statements are true regarding the characteristics of RIPv1? (Choose two).
It is a distance vector routing protocol.
The data portion of a RIP message is encapsulated into a UDP segment.

Which command or set of commands will stop the RIP routing process?
RouterB(config)# no router rip

Refer to the exhibit. All routers in the exhibit are running RIP v1. The network administrator issues the show ip route command on router A. What routes would appear in the routing table output if the network is converged? (Choose two).
R 192.168.2.0/24 [120/1]
R 10.10.1.0/24 [120/2]

Which command will display RIP activity as it occurs on a router?
debug ip rip

Refer to the output from the show ip route command. What can be concluded from the output of this router command?
There are two equal cost paths to network 1.0.0.0.

Refer to the exhibit. Router1 and Router2 are running the RIPv1 protocol. The network administrator configures the command network 10.1.0.0 on Router1. What network will Router1 advertise to Router2?
10.0.0.0/8

Refer to the exhibit. Pings between the serial interfaces of the routers are successful. Hosts on each LAN can ping the Fa0/0 interface of the router to which they are directly connected through the switch. However, pings between hosts on the 10.1.1.0/24 and 10.1.2.0/24 networks are unsuccessful. What is a likely cause of this problem?
RIP is configured incorrectly on R1.

What will happen if an interface IP address is entered for the address portion of the network command in a RIPv1 configuration instead of a network address?
All interfaces in the same classful network as the configured address will be included in the RIPv1 routing process.

Refer to the exhibit. All routers that are shown are running the RIP routing protocol. All unknown IP traffic must be forwarded to the ISP. What router or set of routers are recommended to have both a default route and the default-information originate command issued to implement this forwarding policy?
only the gateway router

Circa 90% =)

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See ya!

Quando una persona diventa programmatore o sistemista, la maggior parte delle volte viene affascinato da cose a cui non dovrebbe nemmeno pensare. Un cristiano potrebbe chiamarle “tentazioni demoniache”, un buddista “ricchezze terrene”, ecc. ecc. Invece sono da evitare il più possibile, e da abbandonare per poter raggiungere la Vera Illuminazione. Vediamone qualcuna.

chmod 777

Questo semplice mantra (che per i file può anche essere “chmod 666″, notate il numero diabolico) permetterà a chiunque di andare a letto con la vostra ragazza, di venire a cena a casa vostra in qualsiasi momento, di “prendere in prestito” la vostra macchina, di leggervi la posta direttamente dalla cassetta, ecc. ecc. ecc.

Seriamente: Questo semplice comando permette, su sistemi Linux e Unix, di accedere a qualsiasi risorsa (a un file, in realtà, ma in Unix/Linux TUTTO è un file) senza alcuna limitazione. Guardatevi da esso, poiché è il male. A parte dare il permesso di esecuzione (che nelle directory serve per poterci entrare, ma nei file rende eseguibile il file stesso) concede pieni poteri sul file a qualsiasi utente: lettura, scrittura, modifica, azzeramento. Forse l’unica cosa che non si può fare è cancellarlo (servono permessi equivalenti sulla sua directory). Può sembrare che risolva tutti i propri problemi (non devo più diventare root per modificarlo!), ma ci sono un sacco di motivi per cui Windows è pieno di virus e Linux no. Il fatto che le distribuzioni non usino mai chmod 777 è uno di questi.

Se un fiile ha un certo set di permessi è proprio perché nessuno, per errore o intenzionalmente, lo modifichi. Aprendo in questo modo i permessi di accesso si consente a programmi impazziti, a servizi bucati da cracker o semplicemente a un errore di digitazione di fare danni seri. Pensate a quale sia la differenza tra un “rm -Rf /” dato da utente (cancella solo i file a cui ha accesso l’utente, quindi solo la sua home e pochi file in /tmp) e dato da root (cancella tutto il sistema operativo).

goto

Qui entriamo nel campo della programmazione. Ormai è risaputo che goto è la fonte di tutti i mali, l’anticristo, il limone sulla Nutella. Lo dicono perfino Dijkstra e Wirth! (I link sono alla Wikipedia italiana, ma quella inglese è più completa). goto vi farà uscire di strada in macchina (goto fosso), vi farà entrare nello sgabuzzino invece che in bagno (goto bin). Potreste perfino finire a letto con un uomo invece che con una ragazza (goto man)! Attenti!

Seriamente: goto, se usato male (e nel 99% dei casi viene usato male) rende “spaghetti-code” i vostri programmi. Fa perdere velocemente il flusso logico delle procedure/funzioni, e porta a errori inaspettati (”ma questo codice non doveva essere eseguito quando questa variabile ha questo valore!”). Linus Torvalds lo può usare perché lui sa quello che fa.

global

Qui parlo in generale delle variabili globali. C’è un motivo per cui sono state inventate la programmazione strutturata e quella ad oggetti. Le variabili globali sono una macchina del tempo rotta, che ci porta solo indietro di 50 anni: guerra (o primo dopoguerra), malattie, dispersi, fame, ecc. ecc.

Seriamente: usare variabili globali è pericoloso quanto e forse più che usare goto: queste variabili possono venire modificate da altre funzioni che non c’entrano niente con quello che stiamo facendo, ed è impossibile sapere con esattezza, guardando il codice, che valore hanno in un certo punto. Passate valori alle funzioni, impostateli in qualche variabile di classe, ma guardatevi sempre dall’usare variabili globali. Hanno senso solo in pochissimi casi, e, se siete dei principianti, in NESSUN caso.

In PHP questo comprende anche l’uso di register_globals. Questa direttiva (che per fortuna verrà disabilitata e sarà reso impossibile abilitarla conla versione 6 di PHP) prende tutte le variabili che arrivano dall’esterno del vostro script (quindi GET e POST, i cookies, i valori in sessione, le variabili d’ambiente) e le mette tutte in un minestrone, rendendole variabili globali. C’è un ordine preciso di “riempimento” di questo minestrone, ma vi sfido a capire, a colpo d’occhio, se una variabile sia stata passata da GET o se arrivi dalla sessione dell’utente. Molto meglio usare le superglobals: $_GET, $_POST, $_COOKIES, $_SESSION e $_ENV (oltre a $_SERVER).

addslashes()/stripslashes()/magic_quotes

Qui si parla specificatamente di PHP. Il giorno che queste funzioni verranno tolte da PHP probabilmente smetterà di piovere folgore dal cielo, o più probabilmente un\\\’infinita\` di pagine web l\’una coi caratteri più sballati dell\\\’altra, e parecchi casi di SQL-injection spariranno dalla rete.

Seriamente: poche cose in una pagina web hanno bisogno delle barre prima di un carattere. Può sembrare giusto prima di infilare una stringa in MySQL (per cui la ‘ è un carattere speciale e, se contenuta in una frase, fa “escapata” con \’), ma, per esempio, in PostgreSQL il modo giusto di fare l’escape è ” (due virgolette singole) e non \’, quindi i vostri script non funzioneranno cambiando DB. Usate mysql_real_escape_string(), pg_escape_string() o, meglio ancora, PDO o un framework come Zend Framework. Per passarle su un URL (un link con <a>, per esempio) la funzione giusta è urlencode(). addslashes non è quasi mai la risposta giusta. Vale la stessa considerazione di global: se siete principianti, addslashes() non è MAI la risposta giusta.

<font>, <b>, <i>, <frame> (guest stars: <table>, <br>)

Entriamo nel mondo del web dalla porta sul retro: HTML. Il poveretto era nato con buonissime intenzioni: l’ipertesto, la digitalizzazione e il collegamento delle informazioni, la diffusione della cultura. Ma tre bambini cattivi (non facciamo nomi, solo iniziali: MS, NS e MM) gli hanno regalato le caramelle fuori dalla scuola, e da allora si sta disintossicando in diverse comunità di recupero. Per fortuna ultimamente ha trovato un bel po’ di amici che lo stanno tirando fuori dal tunnel, ma ci sono ancora un sacco di bambini cattivi in giro!

Seriamente: L’HTML è nato per descrivere la struttura delle informazioni, non la loro rappresentazione sullo schermo. Usare editor WYSIWYG facilita sicuramente lo scrivere pagine web, ma avete mai provato a modificare il posizionamento di un’immagine senza usare quegli editor, o ad aggiungere un’immagine in mezzo alle altre, anche CON quegli editor? Da un po’ il W3C ha preso una posizione netta sulla questione: l’HTML deve descrivere solo COSA è una certa informazione, mentre il COME FARLA VEDERE è compito dei CSS. COME SI COMPORTA è compito di Javascript (o ECMAscript), e con questo il cerchio si chiude. font, b e i sono (finalmente) tag deprecati. Un testo non è “Arial 18px bold italic”, ma “titolo di sezione”, quindi <h2> (per esempio). Una frase importante non è “bold”, ma “importante” (strong) appunto! Prima si impara a usare i tag giusti, meglio è.

Ho messo come guest star <table> e <br> perché si devono ancora usare, ma solo quando è giusto usarli. Non si usa <table> per definire il layout di una pagina, ma solo per intabellare dati. Non si usa <br> per fare spazio con le righe vuote, ma solo per andare a capo senza chiudere un paragrafo (che è <p>).

Una malattia molto diffusa per chi si avvicina ai CSS è la DIVite (accompagnata dalla SPANite): quando non si sa cosa mettere, si mettono un div o uno span, dimenticando che esistono decine di tag che non usa nessuno. Una lista della spesa è <ul>, una lista di passi per una ricetta è una <ol>. Una lista di definizioni da vocabolario è <dl>. Un’etichetta da dare a qualcosa è <label>. La legenda di una tabella è <caption>. Una breve citazione è <q>, mentre una citazione lunga è <blockquote>. Un indirizzo è <address>. Ecc. ecc. Imparate a usare i tag giusti al momento giusto, e il vostro codice sarà molto pià leggibile (e modificabile, che è la cosa più importante). Quando ci sarete arrivati, date un’occhiata anche ai Microformati, tenendo conto che ci sono già estensioni per Firefox che li usano, e che in futuro saranno sempre più diffusi e richiesti. E non dimenticate di impostare il DOCTYPE corretto!

Conclusione

Per ora chiudo qui, ma sono sicuro che ho dimenticato un sacco di cose. La morale è sempre la solita: diffidate delle strade che sembrano troppo semplici. Sicuramente c’è qualcosa che non va.