Unix Quotes

UNIX is basically a simple operating system, but you have to be a genius to understand the simplicity

An ugly system is one in which there are special interfaces for everything you want to do. Unix is the opposite. It gives you the building blocks that are sufficient for doing everything. That's what having a clean design is all about.

Forget UNIX - it will be gone in 5 years.

UTSL, which Maxine at first takes for an anagram of LUST or possibly SLUT but later learns is Unix for “Use The Source, Luke.

Unix is not so much a product as it is a painstakingly compiled oral history of the hacker subculture. It is our Gilgamesh epic: a living body of narrative that many people know by heart, and tell over and over again—making their own personal embellishments whenever it strikes their fancy. The bad embellishments are shouted down, the good ones picked up by others, polished, improved, and, over time, incorporated into the story. […] Thus Unix has slowly accreted around a simple kernel and acquired a kind of complexity and asymmetry about it that is organic, like the roots of a tree, or the branchings of a coronary artery. Understanding it is more like anatomy than physics.

Second by second, the Queng Ho counted from the instant that a human had first set foot on Old Earth's moon. But if you looked at it still more closely ... the starting instant was actually about fifteen million seconds later, the 0-second of one of Humankind's first computer operating systems.

There is a flip side to this. In the Unix world, libraries which are delivered as libraries should come with exerciser programs.

CSV (fields separated by commas, double quotes used to escape commas, no continuation lines) is rarely found under Unix.

Over the years, Rao would master two computer languages, COBOL and BASIC, and would also go on to write code in the mainframe operating system UNIX. Narasimha

elders.’ ” Working in collaboration with a small group of programmers, Joy took on the task of rewriting UNIX, which was a software system

Levchin and Musk soon clashed on an issue that sounded technical but was also theological: whether to use Microsoft Windows or Unix as the main operating system.

The sched_setscheduler() system call changes both the scheduling policy and the priority of the process whose process ID is specified in pid. If pid is specified as 0, the attributes of the calling process are changed.

VI was predecessor to hundreds of word processing systems. By now, Unix folks see it as a bit stodgy—it hasn’t the versatility of Gnu-Emacs, nor the friendliness of more modern editors. Despite that, VI shows up on every Unix system.

When he finally settled down for the interview, he said that even the advent of the web would do little to stop Microsoft’s domination. “Windows has won,” he said. “It beat the Mac, unfortunately, it beat UNIX, it beat OS/2. An inferior product won.

That time in Seattle—during the lawsuit—was a fucking nightmare. I came out of it dead broke, without a house, without anything except a girlfriend and a knowledge of UNIX.” “Well, that’s something,” Avi says. “Normally those two are mutually exclusive.

The name UNIX began as a pun: because early versions of the operating system supported only one user—Ken Thompson—Peter Neumann, a security researcher at Stanford Research International, joked that it was an “emasculated Multics,” or “UNICS.” The spelling was eventually changed to UNIX.

So Apple needed a partner, one that could make a stable operating system, preferably one that was UNIX-like and had an object-oriented application layer. There was one company that could obviously supply such software—NeXT—but it would take a while for Apple to focus on it. Apple first homed in on

But Unix had a serious shortcoming: No common version existed. Over the years different versions of Unix had proliferated like weeds, so that an application written for one would not run unmodified on another. While DOS presented a single target to consumers, applications writers and computer makers, Unix did not.

NeXT and making Jobs its CEO. In the spoof Mike Markkula asked Jobs, “Do you want to spend the rest of your life selling UNIX with a sugarcoating, or change the world?” Jobs responded, “Because I’m now a father, I needed a steadier source of income.” The release noted that “because of his experience at Next, he is expected to bring

Apple’s chief technology officer, Ellen Hancock, argued for going with Sun’s UNIX-based Solaris operating system, even though it did not yet have a friendly user interface. Amelio began to favor using, of all things, Microsoft’s Windows NT, which he felt could be rejiggered on the surface to look and feel just like a Mac while being compatible

Python language is one example. As we noted above, it is also heavily used for mathematical and scientific papers, and will probably dominate that niche for some years yet. 18.3.3

Transparency is therefore more than an esthetic triumph; it is a victory that will be reflected in lower costs throughout the software’s life cycle. 6.2.2

A process is an instance of an executing program. In this section, we elaborate on this definition and clarify the distinction between a program and a process.

As a system administrator, it's in your best interest to befriend data center technicians and bribe them with coffee, caffeinated soft drinks, and alcoholic beverages

graphical user interfaces make easy tasks easy, while command line interfaces make difficult tasks possible

HP-UX is a pretty good implementation of BSD, although it's not as featureful as SunOS.

I’m glad someone’s finally giving ed the attention it deserves.

Chapter 5-"Now THAT'S Leverage" discusses the idea of "software leverage," where reusing components results in greater impact. We see how the use of shell scripts achieves a high degree of leverage.

It might seem that security should gradually improve over time as security problems are discovered and corrected, but unfortunately this does not seem to be the case. System software is growing ever more complicated, hackers are becoming better and better organized, and computers are connecting more and more intimately on the Internet. Security is an ongoing battle that can never really be won.

To understand this first event, you need to know that we rely on Unix and Linux machines to store the thousands of computer files that comprise all the shots of any given film. And on those machines, there is a command—/bin/rm -r -f *—that removes everything on the file system as fast as it can. Hearing that, you can probably anticipate what’s coming: Somehow, by accident, someone used this command on the drives where the Toy Story 2 files were kept. Not just some of the files, either. All of the data that made up the pictures, from objects to backgrounds, from lighting to shading, was dumped out of the system. First, Woody’s hat disappeared. Then his boots. Then he disappeared entirely. One by one, the other characters began to vanish, too: Buzz, Mr. Potato Head, Hamm, Rex. Whole sequences—poof!—were deleted from the drive. Oren

The label “jack-of-all-trades but master of none” is normally meant to be derogatory, implying that the labelee lacks the focus to really dive into a subject and master it. But, when your online shopping application is on the fritz and you’re losing orders by the hundreds as each hour passes, it’s the jack-of-all-trades who not only knows how the application’s code works but can also do low-level UNIX debugging of your web server processes, analyze your RDBMS’s configuration for potential performance bottlenecks, and check your network’s router configuration for hard-to-find problems. And, more important, after finding the problem, the jack-of-all-trades can quickly make architecture and design decisions, implement code fixes, and deploy a new fixed system to production. In this scenario, the manufacturing scenario seems quaint at best and critically flawed at worst.

NIH syndrome is characterized by a decision to discard all of what the other developer accomplished with the intent of demonstrating a superior solution. Such an act of sheer egotism demonstrates little interest in preserving the best of another's work and using it as a springboard to newer heights.

Use # as an introducer for comments. It is good to have a way to embed annotations and comments in data files. It’s best if they’re actually part of the file structure, and so will be preserved by tools that know its format. For comments that are not preserved during parsing, # is the conventional start character.

Top-down tends to be good practice when three preconditions are true: (a) you can specify in advance precisely what the program is to do, (b) the specification is unlikely to change significantly during implementation, and (c) you have a lot of freedom in choosing, at a low level, how the program is to get that job done.

There was, of course, one other option. Two years earlier Macworld magazine columnist (and former Apple software evangelist) Guy Kawasaki had published a parody press release joking that Apple was buying NeXT and making Jobs its CEO. In the spoof Mike Markkula asked Jobs, “Do you want to spend the rest of your life selling UNIX with a sugarcoating, or change the world?” Jobs responded, “Because I’m now a father, I needed a steadier source of income.” The release noted that “because of his experience at Next, he is expected to bring a newfound sense of humility back to Apple.” It also quoted Bill Gates as saying there would now be more innovations from Jobs that Microsoft could copy. Everything in the press release was meant as a joke, of course. But reality has an odd habit of catching up with satire.

When a process is rescheduled to run on a multiprocessor system, it doesn’t necessarily run on the same CPU on which it last executed. The usual reason it may run on another CPU is that the original CPU is already busy. When a process changes CPUs, there is a performance impact: in order for a line of the process’s data to be loaded into the cache of the new CPU, it must first be invalidated (i.e., either discarded if it is unmodified, or flushed to main memory if it was modified), if present in the cache of the old CPU. (To prevent cache inconsistencies, multiprocessor architectures allow data to be kept in only one CPU cache at a time.) This invalidation costs execution time. Because of this performance impact, the Linux (2.6) kernel tries to ensure soft CPU affinity for a process — wherever possible, the process is rescheduled to run on the same CPU.

We need to be humble enough to recognize that unforeseen things can and do happen that are nobody’s fault. A good example of this occurred during the making of Toy Story 2. Earlier, when I described the evolution of that movie, I explained that our decision to overhaul the film so late in the game led to a meltdown of our workforce. This meltdown was the big unexpected event, and our response to it became part of our mythology. But about ten months before the reboot was ordered, in the winter of 1998, we’d been hit with a series of three smaller, random events—the first of which would threaten the future of Pixar. To understand this first event, you need to know that we rely on Unix and Linux machines to store the thousands of computer files that comprise all the shots of any given film. And on those machines, there is a command—/bin/rm -r -f *—that removes everything on the file system as fast as it can. Hearing that, you can probably anticipate what’s coming: Somehow, by accident, someone used this command on the drives where the Toy Story 2 files were kept. Not just some of the files, either. All of the data that made up the pictures, from objects to backgrounds, from lighting to shading, was dumped out of the system. First, Woody’s hat disappeared. Then his boots. Then he disappeared entirely. One by one, the other characters began to vanish, too: Buzz, Mr. Potato Head, Hamm, Rex. Whole sequences—poof!—were deleted from the drive. Oren Jacobs, one of the lead technical directors on the movie, remembers watching this occur in real time. At first, he couldn’t believe what he was seeing. Then, he was frantically dialing the phone to reach systems. “Pull out the plug on the Toy Story 2 master machine!” he screamed. When the guy on the other end asked, sensibly, why, Oren screamed louder: “Please, God, just pull it out as fast as you can!” The systems guy moved quickly, but still, two years of work—90 percent of the film—had been erased in a matter of seconds. An hour later, Oren and his boss, Galyn Susman, were in my office, trying to figure out what we would do next. “Don’t worry,” we all reassured each other. “We’ll restore the data from the backup system tonight. We’ll only lose half a day of work.” But then came random event number two: The backup system, we discovered, hadn’t been working correctly. The mechanism we had in place specifically to help us recover from data failures had itself failed. Toy Story 2 was gone and, at this point, the urge to panic was quite real. To reassemble the film would have taken thirty people a solid year. I remember the meeting when, as this devastating reality began to sink in, the company’s leaders gathered in a conference room to discuss our options—of which there seemed to be none. Then, about an hour into our discussion, Galyn Susman, the movie’s supervising technical director, remembered something: “Wait,” she said. “I might have a backup on my home computer.” About six months before, Galyn had had her second baby, which required that she spend more of her time working from home. To make that process more convenient, she’d set up a system that copied the entire film database to her home computer, automatically, once a week. This—our third random event—would be our salvation. Within a minute of her epiphany, Galyn and Oren were in her Volvo, speeding to her home in San Anselmo. They got her computer, wrapped it in blankets, and placed it carefully in the backseat. Then they drove in the slow lane all the way back to the office, where the machine was, as Oren describes it, “carried into Pixar like an Egyptian pharaoh.” Thanks to Galyn’s files, Woody was back—along with the rest of the movie.

Technologist Kevin Kelly suggests, “If a thousand lines of letters in UNIX qualifies as a technology, . . . then a thousand lines of letters in English (Hamlet) must qualify as well. They both can change our behavior, alter the course of events, or enable future inventions. A Shakespeare sonnet and a Bach fugue, then, are in the same category as Google’s search engine and the iPod. They are something useful produced by a mind.

Mensagem postada na Usenet, 21 de agosto de 1994:   Start-up com bom capital busca programadores de C/C++/Unix muito talentosos para projeto pioneiro de comércio pela internet. É necessário ter experiência em projetar e desenvolver sistemas grandes e complexos (que possam ser atualizados) e ser capaz de fazer isso em um terço do tempo considerado possível. Exigimos bacharelado, mestrado ou Ph.D. em ciência da computação ou formação equivalente. Grande facilidade de comunicação é essencial. É desejável, mas não imprescindível, ter familiaridade com servidores de Web e HTML. Esperamos trabalhar com pessoas talentosas, motivadas, apaixonadas e interessantes que tenham disponibilidade para se mudar para Seattle (ajudaremos com os custos da mudança). Oferecemos uma participação significativa nas ações da empresa. Enviar currículo e carta de apresentação para Jeff Bezos. Endereço: Cadabra Inc. 10.704 N.E. 28th St., Bellevue, WA 98004 Oferecemos as mesmas oportunidades para todos.

Vernor Vinge's novel, A Deepness in the Sky, describes a spacefaring trading civilization tens of thousands of years (hundreds of gigaseconds) in the future that apparently still uses the Unix epoch. The "programmer-archaeologist" responsible for finding and maintaining usable code in mature computer systems first believes that the epoch refers to the time when man first walked on the Moon, but then realizes that it is "the 0-second of one of Humankind’s first computer operating systems.

On a UNIX system, everything is a file; if something is not a file, it is a process.

download the source you must select a file appropriate to your needs from the many that are listed. In addition to selecting the version of sendmail you want, you must choose between two forms of compressed tar(1) distributions. Those that end in . Z are compressed withUnix compress(1); those that end in . gz are compressed withGNU gzip(1). The latter is the preferred form because the file is smaller and therefore quicker to transfer. In addition to the two forms of distribution, each release has a PGP signature file associated withit.* Prior

strongest reasons early adopters of Linux chose it over, say, Windows NT was the powerful command line interface which made the “difficult tasks possible.” What This Book Is About This book is a broad overview of “living” on the Linux command line. Unlike some books that concentrate on just a single program, such as the shell program, bash, this book will try to convey how to get along with the command line interface in a larger sense. How does it all work? What can it do? What's the best way to use it? This is not a book about Linux system administration. While any serious discussion of the command line will invariably lead to system administration topics, this book only touches on a few administration issues. It will, however, prepare the reader for additional study by providing a solid foundation in the use of the command line, an essential tool for any serious system administration task. This book is very Linux-centric. Many other books try to broaden their appeal by including other platforms such as generic Unix and OS X. In doing so, they “water down” their content to feature only general topics. This book, on the other hand, only covers contemporary Linux distributions. Ninety-five percent of the content is useful for users of other Unix-like systems, but this book is highly

Nobody, at least on the Unix side, had any idea they wanted it yet. Everyone uses them now but we had to spend a lot of time explaining to people why this was better than vi and GCC.

from the many that are listed. In addition to selecting the version of sendmail you want, you must choose between two forms of compressed tar(1) distributions. Those that end in . Z are compressed withUnix compress(1); those that end in . gz are compressed withGNU gzip(1). The latter is the preferred form because the file is smaller and therefore quicker to transfer

Fire Fighting Although helping users with their various problems is rarely included in a system administrator’s job description, it claims a significant portion of most administrators’ workdays. System administrators are bombarded with problems ranging from “It worked yesterday and now it doesn’t! What did you change?” to “I spilled coffee on my keyboard! Should I pour water on it to wash it out?” In most cases, your response to these issues affects your perceived value as an administrator far more than does any actual technical skill you might possess. You can either howl at the injustice of it all, or you can delight in the fact that a single well-handled trouble ticket scores as many brownie points as five hours of midnight debugging. You pick!

As a case in point, the ps used by Linux is a trisexual and hermaphroditic version that understands multiple option sets and uses an environment variable to tell it what universe it’s living in.

Unix, BSD, Linux, Mac OS, Windows are Monozukuri.

Это сообщение представлено вам при поддержке Linux, свободного Unix. Windows без X — это как заниматься сексом в одиночку. [пп: пропаганда наркотиков вырезана в соответствии с законодательством РФ, на всякий случай] Яблоки были проблемой еще в Эдеме. Linux — способ избавиться от вирусов в автозагрузке. — mwikholm@at8.abo.fi, MaDsen Wikholm

HP, Oracle(구 SUN)사의 서버는 전용 OS를 별도로 사야만 합니다. 아니 오히려 서버에 잘 맞는 Unix 를 쓰기 위해서 HP, Oracle사의 서버를 사기도 했습니다. 그런데 요즘에는 무료 운영체제인 Linux가 Unix를 충분히 대체할 수 있게 되었습니다. 그래서 대부분 서버에 Linux 를 설치해서 사용합니다.

found on other Unix-like systems. The design is actually specified in a published standard called the Linux Filesystem Hierarchy Standard.

Use manual sanity checks in data pipelines. When optimizing data processing systems, it’s easy to stay in the “binary mindset” mode, using tight pipelines, efficient binary data formats, and compressed I/O. As the data passes through the system unseen, unchecked (except for perhaps its type), it remains invisible until something outright blows up. Then debugging commences. I advocate sprinkling a few simple log messages throughout the code, showing what the data looks like at various internal points of processing, as good practice — nothing fancy, just an analogy to the Unix head command, picking and visualizing a few data points. Not only does this help during the aforementioned debugging, but seeing the data in a human-readable format leads to “aha!” moments surprisingly often, even when all seems to be going well. Strange tokenization! They promised input would always be encoded in latin1! How did a document in this language get in there? Image files leaked into a pipeline that expects and parses text files! These are often insights that go way beyond those offered by automatic type checking or a fixed unit test, hinting at issues beyond component boundaries. Real-world data is messy. Catch early even things that wouldn’t necessarily lead to exceptions or glaring errors. Err on the side of too much verbosity.

To design for compactness and orthogonality, start from zero. Zen teaches that attachment leads to suffering; experience with software design teaches that attachment to unnoticed assumptions leads to non-orthogonality, noncompact designs, and projects that fail or become maintenance nightmares.

first of which would threaten the future of Pixar. To understand this first event, you need to know that we rely on Unix and Linux machines to store the thousands of computer files that comprise all the shots of any given film. And on those machines, there is a command—/bin/rm -r -f *—that removes everything on the file system as fast as it can. Hearing that, you can probably anticipate what’s coming: Somehow, by accident, someone used this command on the drives where the Toy Story 2 files were kept. Not just some of the files, either. All of the data that made up the pictures, from objects to backgrounds, from lighting to shading, was dumped out of the system. First, Woody’s hat disappeared. Then his boots. Then he disappeared entirely. One by one, the other characters began to vanish, too: Buzz, Mr. Potato Head, Hamm, Rex. Whole sequences—poof!—were deleted from the drive.

Convert Text Files from Windows Format to Linux Format and Vice-Versa $ dos2unix $ unix2dos Sooner or later you're going to be sent a file or download one that uses a pair of CR (carriage return) and LF (line feed) characters to terminate lines in the file.  Those type of files are Windows/DOS formatted.  Unix-like operating systems simply use the LF character to terminate a line.  Sometimes this can cause issues.  To convert the file to a unix-like format, use dos2unix.  To examine the line termination characters use "cat -A" or the "file" command. $

Make each program do one thing well. To do a new job, build afresh rather than complicate old programs by adding new features.

When the superior programmer refrains from coding, his force is felt for a thousand miles.

Poor performance was a common failing of most new programs. The annals of software amply showed this; nearly every landmark system, from IBM’s 360 to the various flavors of Unix to Microsoft’s Windows, was released in an immature state and evolved over time to win broader acceptance. Indeed, people expected the first commercial release of a new program to contain flaws of all sorts.

To design the perfect anti-Unix, write an operating system that thinks it knows what you’re doing better than you do. And then adds injury to insult by getting it wrong.

As with buildings, it’s easier to repair superstructure on top of a solid foundation than it is to replace the foundations without trashing the superstructure.

Web pages get bogged down in the dispute over whether the reader or author should control the appearance.

When you feel the urge to design a complex binary file format, or a complex binary application protocol, it is generally wise to lie down until the feeling passes.

Tools that look glossy but shatter under stress are not good long-term value. Unix

One of the main lessons of Zen is that we ordinarily see the world through a haze of preconceptions and fixed ideas that proceed from our desires. To achieve enlightenment, we must follow the Zen teaching not merely to let go of desire and attachment, but to experience reality exactly as it is—without the preconceptions and the fixed ideas getting in the way. This

The nightmare scenario is one in which corporate monopolism and statist power-seeking, always natural allies, feed back into each other and create rationales for increasing regulation, repression, and criminalization of digital speech.

Unix has always lurked provocatively in the background of the operating system wars, like the Russian Army. Most people know it only by reputation, and its reputation, as the Dilbert cartoon suggests, is mixed. But everyone seems to agree that if it could only get its act together and stop surrendering vast tracts of rich agricultural land and hundreds of thousands of prisoners of war to the onrushing invaders, it could stomp them (and all other opposition) flat.

Rule of Optimization: Prototype before polishing. Get it working before you optimize it.

Web Application Development In this modern world of computer technology all people are using internet. In particular, to take advantage of this scenario the web provides a way for marketers to get to know the people visiting their sites and start communicating with them. One way of doing this is asking web visitors to subscribe to newsletters, to submit an application form when requesting information on products or provide details to customize their browsing experience when next visiting a particular website. In computing, a web application is a client–server software application in which the client runs in a web browser. HTML5 introduced explicit language support for making applications that are loaded as web pages, but can store data locally and continue to function while offline. Web Applications are dynamic web sites combined with server side programming which provide functionalities such as interacting with users, connecting to back-end databases, and generating results to browsers. Examples of Web Applications are Online Banking, Social Networking, Online Reservations, eCommerce / Shopping Cart Applications, Interactive Games, Online Training, Online Polls, Blogs, Online Forums, Content Management Systems, etc.. Applications are usually broken into logical chunks called “tiers”, where every tier is assigned a role. Traditional applications consist only of 1 tier, which resides on the client machine, but web applications lend themselves to an n-tiered approach by nature. Though many variations are possible, the most common structure is the three-tiered application. In its most common form, the three tiers are called presentation, application and storage, in this order. A web browser is the first tier (presentation), an engine using some dynamic Web content technology (such as ASP, CGI, ColdFusion, Dart, JSP/Java, Node.js, PHP, Python or Ruby on Rails) is the middle tier (application logic), and a database is the third tier (storage).The web browser sends requests to the middle tier, which services them by making queries and updates against the database and generates a user interface. Client Side Scripting / Coding – Client Side Scripting is the type of code that is executed or interpreted by browsers. Client Side Scripting is generally viewable by any visitor to a site (from the view menu click on “View Source” to view the source code). Below are some common Client Side Scripting technologies: HTML (HyperTextMarkup Language) CSS (Cascading Style Sheets) JavaScript Ajax (Asynchronous JavaScript and XML) jQuery (JavaScript Framework Library – commonly used in Ajax development) MooTools (JavaScript Framework Library – commonly used in Ajax development) Dojo Toolkit (JavaScript Framework Library – commonly used in Ajax development) Server Side Scripting / Coding – Server Side Scripting is the type of code that is executed or interpreted by the web server. Server Side Scripting is not viewable or accessible by any visitor or general public. Below are the common Server Side Scripting technologies: PHP (very common Server Side Scripting language – Linux / Unix based Open Source – free redistribution, usually combines with MySQL database) Zend Framework (PHP’s Object Oriented Web Application Framework) ASP (Microsoft Web Server (IIS) Scripting language) ASP.NET (Microsoft’s Web Application Framework – successor of ASP) ColdFusion (Adobe’s Web Application Framework) Ruby on Rails (Ruby programming’s Web Application Framework – free redistribution) Perl (general purpose high-level programming language and Server Side Scripting Language – free redistribution – lost its popularity to PHP) Python (general purpose high-level programming language and Server Side Scripting language – free redistribution). We also provide Training in various Computer Languages. TRIRID provide quality Web Application Development Services. Call us @ 8980010210

One does not simply Telnet into Mordor.

with anything else under UNIX (of which Finux is a variant), there are a million options that only young, lonely, or obsessed people have the time and patience to explore.

A unifying design principle of UNIX is that a program can’t tell if a person hit return or a program did so. Since real people are slower than simulated people at operating keyboards, the importance of precise timing is suppressed by this particular idea. As a result, UNIX is based on discrete events that don’t have to happen at a precise moment in time.

Over the next 50 years, Vail’s organization—eventually called the Bell Telephone Laboratories—produced the transistor, the solar cell, the CCD chip (used inside every digital camera), the first continuously operating laser, the Unix operating system, the C programming language, and eight Nobel Prizes. Vail created the most successful industrial research lab in history, and AT&T grew into the country’s largest business.

This means that there were two major influences from Unix to Linux—GNU, which remains a prominent component of many different distributions of Linux, and the initial development of Linux done within the MINIX system.

RCS was the first version control tool I used. When I was at Spyglass, we had a team of 50 or so developers across three platforms using RCS on a shared code base. Since RCS never had support for networking, people on Windows and Mac had to log in to the Sun workstation that hosted RCS, FTP their code changes up there, and then check them in from the Unix shell. It was an interesting experience just trying to get all that to work.

The history of Unix should have prepared us for what we’re learning from Linux (and what I’ve verified experimentally on a smaller scale by deliberately copying Linus’s methodsNote 12). That is, while coding remains an essentially solitary activity, the really great hacks come from harnessing the attention and brainpower of entire communities. The developer who uses only his or her own brain in a closed project is going to fall behind the developer who knows how to create an open, evolutionary context in which feedback exploring the design space, code contributions, bug-spotting, and other improvements come from from hundreds (perhaps thousands) of people.

The bank knew exactly what it was looking for and how to go about it. There was consensus on two critical aspects: the system had to be centralized and had to be based on UNIX, even if that meant spending tonnes of money. MicroBanker, a fully integrated online banking automation system, developed by Citicorp Information Technology Industries Ltd (Citil), a Citibank subsidiary, fit the bill, but Citil was not willing to deal with HDFC Bank. A small outfit, Citil thought, would not be able to afford the system. Citil was expanding operations in Africa and Europe and was not too keen to sell the software to a start-up Indian bank. While Citil reluctantly made a presentation on the system, Citibank intervened before a deal could be signed, saying that selling MicroBanker to HDFC Bank could give the Indian bank more muscle as a competitor. Aditya had to call Rajesh Hukku, Citil head, to play ball and he relented. Citil later became i-Flex Solutions Ltd (now Oracle Financial Services Software Ltd).

In 1958 AT&T, the owner of Bell Labs, was served with an antitrust court order that forbade it to ever enter the computer business and that forced it to license any non-telephone inventions to the whole world. This odd ruling turned Unix into a worldwide phenomenon, as it spread from one corner of the computer world to the other.

Usenet bulletin-board posting, August 21, 1994: Well-capitalized start-up seeks extremely talented C/C++/Unix developers to help pioneer commerce on the Internet. You must have experience designing and building large and complex (yet maintainable) systems, and you should be able to do so in about one-third the time that most competent people think possible. You should have a BS, MS, or PhD in Computer Science or the equivalent. Top-notch communication skills are essential. Familiarity with web servers and HTML would be helpful but is not necessary. Expect talented, motivated, intense, and interesting co-workers. Must be willing to relocate to the Seattle area (we will help cover moving costs). Your compensation will include meaningful equity ownership. Send resume and cover letter to Jeff Bezos.

And the next time you’re at a job interview where you need to demonstrate your skills by sharing your screen, establish your dominance early. Use ed.

Thompson, who designed and implemented the first UNIX system, has stated that he much prefers printf debugging.24 But as Baird put it, “If you are a genius like Ken Thompson, you are going to write good code.”25 The rest of us need to move beyond printf debugging to get our code working, as I rapidly discovered once I started working on the internals of Windows NT at Microsoft (the fundamental skill is learning to use a specialized piece of software called a debugger, which can examine the memory of another program).

I once worked on a project in which a software product originally written for UNIX was being redesigned and implemented on Windows NT. Most of the programming team consisted of programmers who had great facility with Windows and Microsoft Visual C++. In no time at all, it seemed, they had generated many screens full of windows and toolbars and dialogues, all with connections to networks and data sources, thousands and thousands of lines of code. But when the inevitable difficulties of debugging came, they seemed at sea. In the face of the usual weird and and unexplainable outcomes, they stood agog. It was left to the UNIX-trained programmers to fix things. The UNIX team members were accustomed to not knowing. Their view of programming as language-as-text gave them the patience to look slowly through the code. In the end, the overall 'productivity' of the system, the fact that it came into being at all, was not the handiwork of tools that sought to make programming seem easy, but the work of engineers who had no fear of 'hard.

As companies move toward distributed systems, Sybase and competing vendors—such as The ASK Group Inc., Informix Software Inc., and Oracle Corp.—are all offering products similar to System 10 . . . . Here we are in the “safe as milk” category, somewhat ironic in light of subsequent revelations about the limitations of Server 10. The innovations presented here are all continuous—performance, functionality, and capacity—and a number of other mainstream vendors are “all offering products similar” to it. Note the emphasis on company and market issues as opposed to product and technology. All of this speaks to mainstream positioning, either tornado or post-tornado. Since there is not a lot of emphasis on cutthroat competition, which one always expects with tornado products, the conclusion one would draw here is that Sybase 10 is on Main Street. Additional Indicators Beyond press coverage, a second source of clues to market status comes from the behavior of other companies in the infrastructure. Lew Platt at HP, for example, realized that their commercial Unix server business was in the tornado when software vendors were calling him rather than the other way around. Going further, when a tornado is under way, the easiest way to spot the gorilla is to look for the

One of the many consequences of the exponential power-versus-time curve in computing, and the corresponding pace of software development, is that 50% of what one knows becomes obsolete over every 18 months.

During those same years, there were other achievements at Bell Labs that would, in time, alter the world. One occurred when several computer scientists at Murray Hill got together to write a revolutionary computer operating system they called Unix, which was written in a new computer language called C.

John Hennessy and David Patterson: they are titled Computer Organization and Design: The Hardware/Software Interface and Computer Architecture: A Quantitative Approach (both published by Morgan Kaufmann).

NCA uses a kernel module to transparently cache static web content in a kernel memory buffer, and replies to HTTP document requests for documents in its cache without ever waking up the application web server.

- ¿Que opción del comando ls puede ser usado para listar archivos y directorios de forma recursiva?

However, universities could not modify UNIX to suit their individual needs. AT&T retained rights to the source code, which prohibited any alteration of

The history of Linux is long and complex, but we can provide a quick overview here. During the late 1960s and 1970s, AT&T's Bell Labs developed the UNIX operating system. UNIX was a powerful operating system, and universities across the United States soon used it in their computer labs.

Un shell permite ser ejecutado de forma interactiva cuando acepta comandos directamente desde el teclado, no interactivos cuando aceptas comandos que provienen de un archivo.

By mid-1970, they had a preliminary version up and running. Somewhere along the way, moreover, their homebrew operating system had acquired a name. According to one version of the story, the name signified “one of whatever Multics was many of.” According to another, it stood for “Multics without balls.” But either way it came out the same: Unix.

collect all the code that had to be customized for each new computer or disk drive and put it into a small Unix-like kernel that he called the Basic Input/Output System, or BIOS.

It's times like this when the age of the universe becomes a useful unit of measurement: 64-bit Unix time will last until twenty-one times the age of the universe from now - until (assuming we don't manage another upgrade in the meantime) December 4 in the year 292,277,026,596 CE, when all the computers will go down. On a Sunday.

The first represents the amount of time required to read or write a given location in memory, and is called the memory access time.

second, the memory cycle time, describes how frequently you can repeat a memory reference.

If a process tries to write to a shared page, it incurs a copy-on-write fault.[5

kswapd’s behavior is controlled by three parameters, called tries_base, tries_min, and swap_cluster,

system that is paging is writing selected, infrequently used pages of memory to disk,

while a system that is swapping is writing entire processes from memory to disk.

Paging is not necessarily indicative of a problem; it is the action of the page scanner to try and increase the size of the free list by moving inactive pages to disk.