"Stephenson,_Neal_-_In_the_Beginning_was_the_Command_Line" - читать интересную книгу автора (Stephenson Neal)
(2) a copy of a Dilbert cartoon in which Dilbert, the long-suffering corporate software engineer, encounters a portly, bearded, hairy man of a certain age--a bit like Santa Claus, but darker, with a certain edge about him. Dilbert recognizes this man, based upon his appearance and affect, as a Unix hacker, and reacts with a certain mixture of nervousness, awe, and hostility. Dilbert jabs weakly at the disturbing interloper for a couple of frames; the Unix hacker listens with a kind of infuriating, beatific calm, then, in the last frame, reaches into his pocket. "Here's a nickel, kid," he says, "go buy yourself a real computer."
(3) the owner of the door, and the cartoon, was one Doug Barnes. Barnes was known to harbor certain heretical opinions on the subject of operating systems. Unlike most Bay Area techies who revered the Macintosh, considering it to be a true hacker's machine, Barnes was fond of pointing out that the Mac, with its hermetically sealed architecture, was actually hostile to hackers, who are prone to tinkering and dogmatic about openness. By contrast, the IBM-compatible line of machines, which can easily be taken apart and plugged back together, was much more hackable.
So when I got home I began messing around with Linux, which is one of many, many different concrete implementations of the abstract, Platonic ideal called Unix. I was not looking forward to changing over to a new OS, because my credit cards were still smoking from all the money I'd spent on Mac hardware over the years. But Linux's great virtue was, and is, that it would run on exactly the same sort of hardware as the Microsoft OSes--which is to say, the cheapest hardware in existence. As if to demonstrate why this was a great idea, I was, within a week or two of returning home, able to get my hand on a then-decent computer (a 33-MHz 486 box) for free, because I knew a guy who worked in an office where they were simply being thrown away. Once I got it home, I yanked the hood off, stuck my hands in, and began switching cards around. If something didn't work, I went to a used-computer outlet and pawed through a bin full of components and bought a new card for a few bucks.
The availability of all this cheap but effective hardware was an unintended consequence of decisions that had been made more than a decade earlier by IBM and Microsoft. When Windows came out, and brought the GUI to a much larger market, the hardware regime changed: the cost of color video cards and high-resolution monitors began to drop, and is dropping still. This free-for-all approach to hardware meant that Windows was unavoidably clunky compared to MacOS. But the GUI brought computing to such a vast audience that volume went way up and prices collapsed. Meanwhile Apple, which so badly wanted a clean, integrated OS with video neatly integrated into processing hardware, had fallen far behind in market share, at least partly because their beautiful hardware cost so much.
But the price that we Mac owners had to pay for superior aesthetics and engineering was not merely a financial one. There was a cultural price too, stemming from the fact that we couldn't open up the hood and mess around with it. Doug Barnes was right. Apple, in spite of its reputation as the machine of choice of scruffy, creative hacker types, had actually created a machine that discouraged hacking, while Microsoft, viewed as a technological laggard and copycat, had created a vast, disorderly parts bazaar--a primordial soup that eventually self-assembled into Linux.
THE HOLE HAWG OF OPERATING SYSTEMS
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.
It is difficult to explain how Unix has earned this respect without going into mind-smashing technical detail. Perhaps the gist of it can be explained by telling a story about drills.
The Hole Hawg is a drill made by the Milwaukee Tool Company. If you look in a typical hardware store you may find smaller Milwaukee drills but not the Hole Hawg, which is too powerful and too expensive for homeowners. The Hole Hawg does not have the pistol-like design of a cheap homeowner's drill. It is a cube of solid metal with a handle sticking out of one face and a chuck mounted in another. The cube contains a disconcertingly potent electric motor. You can hold the handle and operate the trigger with your index finger, but unless you are exceptionally strong you cannot control the weight of the Hole Hawg with one hand; it is a two-hander all the way. In order to fight off the counter-torque of the Hole Hawg you use a separate handle (provided), which you screw into one side of the iron cube or the other depending on whether you are using your left or right hand to operate the trigger. This handle is not a sleek, ergonomically designed item as it would be in a homeowner's drill. It is simply a foot-long chunk of regular galvanized pipe, threaded on one end, with a black rubber handle on the other. If you lose it, you just go to the local plumbing supply store and buy another chunk of pipe.
During the Eighties I did some construction work. One day, another worker leaned a ladder against the outside of the building that we were putting up, climbed up to the second-story level, and used the Hole Hawg to drill a hole through the exterior wall. At some point, the drill bit caught in the wall. The Hole Hawg, following its one and only imperative, kept going. It spun the worker's body around like a rag doll, causing him to knock his own ladder down. Fortunately he kept his grip on the Hole Hawg, which remained lodged in the wall, and he simply dangled from it and shouted for help until someone came along and reinstated the ladder.
I myself used a Hole Hawg to drill many holes through studs, which it did as a blender chops cabbage. I also used it to cut a few six-inch-diameter holes through an old lath-and-plaster ceiling. I chucked in a new hole saw, went up to the second story, reached down between the newly installed floor joists, and began to cut through the first-floor ceiling below. Where my homeowner's drill had labored and whined to spin the huge bit around, and had stalled at the slightest obstruction, the Hole Hawg rotated with the stupid consistency of a spinning planet. When the hole saw seized up, the Hole Hawg spun itself and me around, and crushed one of my hands between the steel pipe handle and a joist, producing a few lacerations, each surrounded by a wide corona of deeply bruised flesh. It also bent the hole saw itself, though not so badly that I couldn't use it. After a few such run-ins, when I got ready to use the Hole Hawg my heart actually began to pound with atavistic terror.
But I never blamed the Hole Hawg; I blamed myself. The Hole Hawg is dangerous because it does exactly what you tell it to. It is not bound by the physical limitations that are inherent in a cheap drill, and neither is it limited by safety interlocks that might be built into a homeowner's product by a liability-conscious manufacturer. The danger lies not in the machine itself but in the user's failure to envision the full consequences of the instructions he gives to it.
A smaller tool is dangerous too, but for a completely different reason: it tries to do what you tell it to, and fails in some way that is unpredictable and almost always undesirable. But the Hole Hawg is like the genie of the ancient fairy tales, who carries out his master's instructions literally and precisely and with unlimited power, often with disastrous, unforeseen consequences.
Pre-Hole Hawg, I used to examine the drill selection in hardware stores with what I thought was a judicious eye, scorning the smaller low-end models and hefting the big expensive ones appreciatively, wishing I could afford one of them babies. Now I view them all with such contempt that I do not even consider them to be real drills--merely scaled-up toys designed to exploit the self-delusional tendencies of soft-handed homeowners who want to believe that they have purchased an actual tool. Their plastic casings, carefully designed and focus-group-tested to convey a feeling of solidity and power, seem disgustingly flimsy and cheap to me, and I am ashamed that I was ever bamboozled into buying such knicknacks.
It is not hard to imagine what the world would look like to someone who had been raised by contractors and who had never used any drill other than a Hole Hawg. Such a person, presented with the best and most expensive hardware-store drill, would not even recognize it as such. He might instead misidentify it as a child's toy, or some kind of motorized screwdriver. If a salesperson or a deluded homeowner referred to it as a drill, he would laugh and tell them that they were mistaken--they simply had their terminology wrong. His interlocutor would go away irritated, and probably feeling rather defensive about his basement full of cheap, dangerous, flashy, colorful tools.
Unix is the Hole Hawg of operating systems, and Unix hackers, like Doug Barnes and the guy in the Dilbert cartoon and many of the other people who populate Silicon Valley, are like contractor's sons who grew up using only Hole Hawgs. They might use Apple/Microsoft OSes to write letters, play video games, or balance their checkbooks, but they cannot really bring themselves to take these operating systems seriously.
THE ORAL TRADITION
Unix is hard to learn. The process of learning it is one of multiple small epiphanies. Typically you are just on the verge of inventing some necessary tool or utility when you realize that someone else has already invented it, and built it in, and this explains some odd file or directory or command that you have noticed but never really understood before.
For example there is a command (a small program, part of the OS) called whoami, which enables you to ask the computer who it thinks you are. On a Unix machine, you are always logged in under some name--possibly even your own! What files you may work with, and what software you may use, depends on your identity. When I started out using Linux, I was on a non-networked machine in my basement, with only one user account, and so when I became aware of the whoami command it struck me as ludicrous. But once you are logged in as one person, you can temporarily switch over to a pseudonym in order to access different files. If your machine is on the Internet, you can log onto other computers, provided you have a user name and a password. At that point the distant machine becomes no different in practice from the one right in front of you. These changes in identity and location can easily become nested inside each other, many layers deep, even if you aren't doing anything nefarious. Once you have forgotten who and where you are, the whoami command is indispensible. I use it all the time.
The file systems of Unix machines all have the same general structure. On your flimsy operating systems, you can create directories (folders) and give them names like Frodo or My Stuff and put them pretty much anywhere you like. But under Unix the highest level--the root--of the filesystem is always designated with the single character "/" and it always contains the same set of top-level directories:
/usr /etc /var /bin /proc /boot /home /root /sbin /dev /lib /tmp
and each of these directories typically has its own distinct structure of subdirectories. Note the obsessive use of abbreviations and avoidance of capital letters; this is a system invented by people to whom repetitive stress disorder is what black lung is to miners. Long names get worn down to three-letter nubbins, like stones smoothed by a river.
| © 2025 Библиотека RealLib.org (support [a t] reallib.org) |