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ΓòÉΓòÉΓòÉ 1. Appendix A: Hacker Folklore ΓòÉΓòÉΓòÉ

This appendix contains several legends and fables that illuminate the meaning
of various entries in the lexicon.


ΓòÉΓòÉΓòÉ 1.1. The Meaning of 'Hack' ΓòÉΓòÉΓòÉ

"The word hack doesn't really have 69 different meanings", according to MIT
hacker Phil Agre.  "In fact, hack has only one meaning, an extremely subtle and
profound one which defies articulation.  Which connotation is implied by a
given use of the word depends in similarly profound ways on the context.
Similar remarks apply to a couple of other hacker words, most notably random."

Hacking might be characterized as 'an appropriate application of ingenuity'.
Whether the result is a quick-and-dirty patchwork job or a carefully crafted
work of art, you have to admire the cleverness that went into it.

An important secondary meaning of hack is 'a creative practical joke'. This
kind of hack is easier to explain to non-hackers than the programming kind.  Of
course, some hacks have both natures; see the lexicon entries for pseudo and
kgbvax.  But here are some examples of pure practical jokes that illustrate the
hacking spirit:

   In 1961, students from Caltech (California Institute of Technology,
   in Pasadena) hacked the Rose Bowl football game.  One student posed
   as a reporter and 'interviewed' the director of the University of
   Washington card stunts (such stunts involve people in the stands
   who hold up colored cards to make pictures).  The reporter learned
   exactly how the stunts were operated, and also that the director
   would be out to dinner later.

   While the director was eating, the students (who called themselves
   the 'Fiendish Fourteen') picked a lock and stole a blank direction
   sheet for the card stunts.  They then had a printer run off 2300
   copies of the blank.  The next day they picked the lock again and
   stole the master plans for the stunts --- large sheets of graph
   paper colored in with the stunt pictures.  Using these as a guide,
   they made new instructions for three of the stunts on the
   duplicated blanks.  Finally, they broke in once more, replacing the
   stolen master plans and substituting the stack of diddled
   instruction sheets for the original set.

   The result was that three of the pictures were totally different.
   Instead of 'WASHINGTON', the word ''CALTECH' was flashed.  Another
   stunt showed the word 'HUSKIES', the Washington nickname, but
   spelled it backwards.  And what was supposed to have been a picture
   of a husky instead showed a beaver.  (Both Caltech and MIT use the
   beaver --- nature 's engineer --- as a mascot.)

   After the game, the Washington faculty athletic representative
   said: "Some thought it ingenious; others were indignant."  The
   Washington student body president remarked: "No hard feelings, but
   at the time it was unbelievable.  We were amazed."

This is now considered a classic hack, particularly because revising the
direction sheets constituted a form of programming.

Here is another classic hack:

   On November 20, 1982, MIT hacked the Harvard-Yale football game.
   Just after Harvard's second touchdown against Yale, in the first
   quarter, a small black ball popped up out of the ground at the
   40-yard line, and grew bigger, and bigger, and bigger.  The letters
   'MIT' appeared all over the ball.  As the players and officials
   stood around gawking, the ball grew to six feet in diameter and
   then burst with a bang and a cloud of white smoke.

   The 'Boston Globe' later reported: "If you want to know the truth,
   MIT won The Game."

   The prank had taken weeks of careful planning by members of MIT's
   Delta Kappa Epsilon fraternity.  The device consisted of a weather
   balloon, a hydraulic ram powered by Freon gas to lift it out of the
   ground, and a vacuum-cleaner motor to inflate it.  They made eight
   separate expeditions to Harvard Stadium between 1 and 5 A.M.,
   locating an unused 110-volt circuit in the stadium and running
   buried wires from the stadium circuit to the 40-yard line, where
   they buried the balloon device.  When the time came to activate the
   device, two fraternity members had merely to flip a circuit breaker
   and push a plug into an outlet.

   This stunt had all the earmarks of a perfect hack: surprise,
   publicity, the ingenious use of technology, safety, and
   harmlessness.  The use of manual control allowed the prank to be
   timed so as not to disrupt the game (it was set off between plays,
   so the outcome of the game would not be unduly affected).  The
   perpetrators had even thoughtfully attached a note to the balloon
   explaining that the device was not dangerous and contained no
   explosives.

   Harvard president Derek Bok commented: "They have an awful lot of
   clever people down there at MIT, and they did it again."  President
   Paul E. Gray of MIT said: "There is absolutely no truth to the
   rumor that I had anything to do with it, but I wish there were."

The hacks above are  verifiable history; they can be proved to have happened.
Many other classic-hack stories from MIT and elsewhere, though retold as
history, have the characteristics of what Jan Brunvand has called 'urban
folklore' (see FOAF).  Perhaps the best known of these is the legend of the
infamous trolley-car hack, an alleged incident in which engineering students
are said to have welded a trolley car to its tracks with thermite.  Numerous
versions of this have been recorded from the 1940s to the present, most set at
MIT but at least one very detailed version set at CMU.

Brian Leibowitz has researched MIT hacks both real and mythical extensively;
the interested reader is referred to his delightful pictorial compendium 'The
Journal of the Institute for Hacks, Tomfoolery, and Pranks' (MIT Museum, 1990;
ISBN 0-917027-03-5).

Finally, here is a story about one of the classic computer hacks.

   Back in the mid-1970s, several of the system support staff at
   Motorola discovered a relatively simple way to crack system
   security on the Xerox CP-V timesharing system.  Through a simple
   programming strategy, it was possible for a user program to trick
   the system into running a portion of the program in 'master mode'
   (supervisor state), in which memory protection does not apply.  The
   program could then poke a large value into its 'privilege level'
   byte (normally write-protected) and could then proceed to bypass
   all levels of security within the file-management system, patch the
   system monitor, and do numerous other interesting things.  In
   short, the barn door was wide open.

   Motorola quite properly reported this problem to Xerox via an
   official 'level 1 SIDR' (a bug report with an intended urgency of
   'needs to be fixed yesterday').  Because the text of each SIDR was
   entered into a database that could be viewed by quite a number of
   people, Motorola followed the approved procedure: they simply
   reported the problem as 'Security SIDR', and attached all of the
   necessary documentation, ways-to-reproduce, etc.

   The CP-V people at Xerox sat on their thumbs; they either didn't
   realize the severity of the problem, or didn't assign the necessary
   operating-system-staff resources to develop and distribute an
   official patch.

   Months passed.  The Motorola guys pestered their Xerox
   field-support rep, to no avail.  Finally they decided  to take
   direct action, to demonstrate to Xerox management just how easily
   the system could be cracked and just how thoroughly the security
   safeguards could be subverted.

   They dug around in the operating-system listings and devised a
   thoroughly devilish set of patches.  These patches were then
   incorporated into a pair of programs called 'Robin Hood' and 'Friar
   Tuck'.  Robin Hood and Friar Tuck were designed to run as 'ghost
   jobs' (daemons, in UNIX terminology); they would use the existing
   loophole to subvert system security, install the necessary patches,
   and then keep an eye on one another's statuses in order to keep the
   system operator (in effect, the superuser) from aborting them.

   One fine day, the system operator on the main CP-V software
   development system in El Segundo was surprised by a number of
   unusual phenomena.  These included the following:

    * Tape drives would rewind and dismount their tapes in the
     middle of a job.
    * Disk drives would seek back and forth so rapidly that they
     would attempt to walk across the floor (see walking drives).
    * The card-punch output device would occasionally start up of
     itself and punch a lace card.  These would usually jam in
     the punch.
    * The console would print snide and insulting messages from
     Robin Hood to Friar Tuck, or vice versa.
    * The Xerox card reader had two output stackers; it could be
     instructed to stack into A, stack into B, or stack into A
     (unless a card was unreadable, in which case the bad card was
     placed into stacker B).  One of the patches installed by the
     ghosts added some code to the card-reader driver... after
     reading a card, it would flip over to the opposite stacker.
     As a result, card decks would divide themselves in half when
     they were read, leaving the operator to recollate them
     manually.

   Naturally, the operator called in the operating-system developers.
   They found the bandit ghost jobs running, and X'ed them... and were
   once again surprised.  When Robin Hood was X'ed, the following
   sequence of events took place:

     !X id1

     id1: Friar Tuck... I am under attack!  Pray save me!
     id1: Off (aborted)

     id2: Fear not, friend Robin!  I shall rout the Sheriff
        of Nottingham's men!

     id1: Thank you, my good fellow!

   Each ghost-job would detect the fact that the other had been
   killed, and would start a new copy of the recently slain program
   within a few milliseconds.  The only way to kill both ghosts was to
   kill them simultaneously (very difficult) or to deliberately crash
   the system.

   Finally, the system programmers  did the latter --- only to find
   that the bandits appeared once again when the system rebooted!  It
   turned out that these two programs had patched the boot-time OS
   image (the kernel file, in UNIX terms) and had added themselves to
   the list of programs that were to be started at boot time.

   The Robin Hood and Friar Tuck ghosts were finally eradicated when
   the system staff rebooted the system from a clean boot-tape and
   reinstalled the monitor.  Not long thereafter, Xerox released a
   patch for this problem.

   It is alleged that Xerox filed a complaint with Motorola's management
   about the merry-prankster actions of the two employees in question.
   It is not recorded that any serious disciplinary action was taken
   against either of them.


ΓòÉΓòÉΓòÉ 1.2. TV Typewriters ΓòÉΓòÉΓòÉ

A Tale of Hackish Ingenuity

Here is a true story about a glass tty: One day an MIT hacker was in a
motorcycle accident and broke his leg.  He had to stay in the hospital quite a
while, and got restless because he couldn't hack.  Two of his friends therefore
took a terminal and a modem for it to the hospital, so that he could use the
computer by telephone from his hospital bed.

Now this happened some years before the spread of home computers, and computer
terminals were not a familiar sight to the average person. When the two friends
got to the hospital, a guard stopped them and asked what they were carrying.
They explained that they wanted to take a computer terminal to their friend who
was a patient.

The guard got out his list of things that patients were permitted to have in
their rooms: TV, radio, electric razor, typewriter, tape player, the guard
wouldn't let it in.  Rules are rules, you know.  (This guard was clearly a
droid.)

Fair enough, said the two friends, and they left again.  They were frustrated,
of course, because they knew that the terminal was as harmless as a TV or
anything else on the list... which gave them an idea.

The next day they returned, and the same thing happened: a guard stopped them
and asked what they were carrying.  They said: "This is a TV typewriter!"  The
guard was skeptical, so they plugged it in and demonstrated it.  "See?  You
just type on the keyboard and what you type shows up on the TV screen."  Now
the guard didn't stop to think about how utterly useless a typewriter would be
that didn't produce any paper copies of what you typed; but this was clearly a
TV typewriter, no doubt about it.  So he checked his list: "A TV is all right,
a typewriter is all right ... okay, take it on in!"


ΓòÉΓòÉΓòÉ 1.3. Two Stories About 'Magic' ΓòÉΓòÉΓòÉ

(by GLS)

Some years ago, I was snooping around in the cabinets that housed the MIT AI
Lab's PDP-10, and noticed a little switch glued to the frame of one cabinet.
It was obviously a homebrew job, added by one of the lab's hardware hackers (no
one knows who).

You don't touch an unknown switch on a computer without knowing what it does,
because you might crash the computer.  The switch was labeled in a most
unhelpful way.  It had two positions, and scrawled in pencil on the metal
switch body were the words 'magic' and 'more magic'.  The switch was in the
'more magic' position.

I called another hacker over to look at it.  He had never seen the switch
before either.  Closer examination revealed that the switch had only one wire
running to it!  The other end of the wire did disappear into the maze of wires
inside the computer, but it's a basic fact of electricity that a switch can't
do anything unless there are two wires connected to it.  This switch had a wire
connected on one side and no wire on its other side.

It was clear that this switch was someone's idea of a silly joke. Convinced by
our reasoning that the switch was inoperative, we flipped it.  The computer
instantly crashed.

Imagine our utter astonishment.  We wrote it off as coincidence, but
nevertheless restored the switch to the 'more magic' position before reviving
the computer.

A year later, I told this story to yet another hacker, David Moon as I recall.
He clearly doubted my sanity, or suspected me of a supernatural belief in the
power of this switch, or perhaps thought I was fooling him with a bogus saga.
To prove it to him, I showed him the very switch, still glued to the cabinet
frame with only one wire connected to it, still in the 'more magic' position.
We scrutinized the switch and its lone connection, and found that the other end
of the wire, though connected to the computer wiring, was connected to a ground
pin.  That clearly made the switch doubly useless: not only was it electrically
nonoperative, but it was connected to a place that couldn't affect anything
anyway.  So we flipped the switch.

The computer promptly crashed.

This time we ran for Richard Greenblatt, a long-time MIT hacker, who was close
at hand.  He had never noticed the switch before, either.  He inspected it,
concluded it was useless, got some diagonal cutters and diked it out.  We then
revived the computer and it has run fine ever since.

We still don't know how the switch crashed the machine.  There is a theory that
some circuit near the ground pin was marginal, and flipping the switch changed
the electrical capacitance enough to upset the circuit as millionth-of-a-second
pulses went through it.  But we'll never know for sure; all we can really say
is that the switch was magic.

I still have that switch in my basement.  Maybe I'm silly, but I usually keep
it set on 'more magic'.


ΓòÉΓòÉΓòÉ 1.4. A Selection of AI Koans ΓòÉΓòÉΓòÉ

These are some of the funniest examples of a genre of jokes told at the MIT AI
Lab about various noted hackers.  The original koans were composed by Danny
Hillis.  In reading these, it is at least useful to know that Minsky, Sussman,
and Drescher are AI researchers of note, that Tom Knight was one of the Lisp
machine's principal designers, and that David Moon wrote much of Lisp machine
Lisp.

                                      * * *

A novice was trying to fix a broken Lisp machine by turning the power off and
on.

Knight, seeing what the student was doing, spoke sternly: "You cannot fix a
machine by just power-cycling it with no understanding of what is going wrong."

Knight turned the machine off and on.

The machine worked.

                                      * * *

One day a student came to Moon and said: "I understand how to make a better
garbage collector.  We must keep a reference count of the pointers to each
cons."

Moon patiently told the student the following story:

   "One day a student came to Moon and said: 'I understand how to make
   a better garbage collector...

[Ed. note: Pure reference-count garbage collectors have problems with circular
structures that point to themselves.]

                                      * * *

In the days when Sussman was a novice, Minsky once came to him as he sat
hacking at the PDP-6.

"What are you doing?", asked Minsky.

"I am training a randomly wired neural net to play Tic-Tac-Toe" Sussman
replied.

"Why is the net wired randomly?", asked Minsky.

"I do not want it to have any preconceptions of how to play", Sussman said.

Minsky then shut his eyes.

"Why do you close your eyes?", Sussman asked his teacher.

"So that the room will be empty."

At that moment, Sussman was enlightened.

                                      * * *

A disciple of another sect once came to Drescher as he was eating his morning
meal.

"I would like to give you this personality test", said the outsider, "because I
want you to be happy."

Drescher took the paper that was offered him and put it into the toaster,
saying: "I wish the toaster to be happy, too."


ΓòÉΓòÉΓòÉ 1.5. OS and JEDGAR ΓòÉΓòÉΓòÉ

This story says a lot about the the ITS ethos.

On the ITS system there was a program that allowed you to see what was being
printed on someone else's terminal.  It spied on the other guy's output by
examining the insides of the monitor system.  The output spy program was called
OS.  Throughout the rest of the computer science (and at IBM too) OS means
'operating system', but among old-time ITS hackers it almost always meant
'output spy'.

OS could work because ITS purposely had very little in the way of 'protection'
that prevented one user from trespassing on another's areas.  Fair is fair,
however.  There was another program that would automatically notify you if
anyone started to spy on your output.  It worked in exactly the same way, by
looking at the insides of the operating system to see if anyone else was
looking at the insides that had to do with your output.  This 'counterspy'
program was called JEDGAR (a six-letterism pronounced as two syllables:
/jed'gr/), in honor of the former head of the FBI.

But there's more.  JEDGAR would ask the user for 'license to kill'.  If the
user said yes, then JEDGAR would actually gun the job of the luser who was
spying.  Unfortunately, people found that this made life too violent,
especially when tourists learned about it.  One of the systems hackers solved
the problem by replacing JEDGAR with another program that only pretended to do
its job.  It took a long time to do this, because every copy of JEDGAR had to
be patched.  To this day no one knows how many people never figured out that
JEDGAR had been defanged.


ΓòÉΓòÉΓòÉ 1.6. The Story of Mel, a Real Programmer ΓòÉΓòÉΓòÉ

This was posted to USENET by its author, Ed Nather (utastro!nather), on May 21,
1983.

   A recent article devoted to the macho side of programming
   made the bald and unvarnished statement:

     Real Programmers write in FORTRAN.

   Maybe they do now,
   in this decadent era of
   Lite beer, hand calculators, and "user-friendly" software
   but back in the Good Old Days,
   when the term "software" sounded funny
   and Real Computers were made out of drums and vacuum tubes,
   Real Programmers wrote in machine code.
   Not FORTRAN. Not RATFOR.  Not, even, assembly language.
   Machine Code.
   Raw, unadorned, inscrutable hexadecimal numbers.
   Directly.

   Lest a whole new generation of programmers
   grow up in ignorance of this glorious past,
   I feel duty-bound to describe,
   as best I can through the generation gap,
   how a Real Programmer wrote code.
   I'll call him Mel,
   because that was his name.

   I first met Mel when I went to work for Royal McBee Computer Corp.,
   a now-defunct subsidiary of the typewriter company.
   The firm manufactured the LGP-30,
   a small, cheap (by the standards of the day)
   drum-memory computer,
   and had just started to manufacture
   the RPC-4000, a much-improved,
   bigger, better, faster --- drum-memory computer.
   Cores cost too much,
   and weren't here to stay, anyway.
   (That's why you haven't heard of the company, or the computer.)

   I had been hired to write a FORTRAN compiler
   for this new marvel and Mel was my guide to its wonders.
   Mel didn't approve of compilers.

   "If a program can't rewrite its own code",
   he asked, "what good is it?"

   Mel had written,
   in hexadecimal,
   the most popular computer program the company owned.
   It ran on the LGP-30
   and played blackjack with potential customers
   at computer shows.
   Its effect was always dramatic.
   The LGP-30 booth was packed at every show,
   and the IBM salesmen stood around
   talking to each other.
   Whether or not this actually sold computers
   was a question we never discussed.

   Mel's job was to re-write
   the blackjack program for the RPC-4000.
   (Port?  What does that mean?)
   The new computer had a one-plus-one
   addressing scheme,
   in which each machine instruction,
   in addition to the operation code
   and the address of the needed  operand,
   had a second address that indicated where, on the revolving drum,
   the next instruction was located.

   In modern parlance,
   every single instruction was followed by a GO TO!
   Put that in Pascal's pipe and smoke it.

   Mel loved the RPC-4000
   because he could optimize his code:
   that is, locate instructions on the drum
   so that just as one finished its job,
   the next would be just arriving at the "read head"
   and available for immediate execution.
   There was a program to do that job,
   an "optimizing assembler",
   but Mel refused to use it.

   "You never know where it's going to put things",
   he explained, "so you'd have to use separate constants".

   It was a long time before I understood that remark.
   Since Mel knew the numerical value
   of every operation code,
   and assigned his own drum addresses,
   every instruction he wrote could also be considered
   a numerical constant.
   He could pick up an earlier "add" instruction, say,
   and multiply by it,
   if it had the right numeric value.
   His code was not easy for someone else to modify.

   I compared Mel's hand-optimized programs
   with the same code massaged by the optimizing assembler program,
   and Mel's always ran faster.
   That was because the "top-down" method of program design
   hadn't been invented yet,
   and Mel wouldn't have used it anyway.
   He wrote the innermost parts of his program loops first,
   so they would get first choice
   of the optimum address locations on the drum.
   The optimizing assembler wasn't smart enough to do it that way.

   Mel never wrote time-delay loops, either,
   even when the balky Flexowriter
   required a delay between output characters to work right.
   He just located instructions on the drum
   so each successive one was just past the read head
   when it was needed;
   the drum had to execute another complete revolution
   to find the next instruction.
   He coined an unforgettable term for this procedure.
   Although "optimum" is an absolute term,
   like "unique", it became common verbal practice
   to make it relative:
   "not quite optimum" or "less optimum"
   or "not very optimum".
   Mel called the maximum time-delay locations
   the "most pessimum".

   After he finished the blackjack program
   and got it to run
   ("Even the initializer is optimized",
   he said proudly),
   he got a Change Request from the sales department.
   The program used an elegant (optimized)
   random number generator
   to shuffle the "cards" and deal from the "deck",
   and some of the salesmen felt it was too fair,
   since sometimes the customers lost.
   They wanted Mel to modify the program
   so, at the setting of a sense  switch on the console,
   they could change the odds and let the customer win.

   Mel balked.
   He felt this was patently dishonest,
   which it was,
   and that it impinged on his personal integrity as a programmer,
   which it did,
   so he refused to do it.
   The Head Salesman talked to Mel,
   as did the Big Boss and, at the boss's urging,
   a few Fellow Programmers.
   Mel finally gave in and wrote the code,
   but he got the test backwards,
   and, when the sense switch was turned on,
   the program would cheat, winning every time.
   Mel was delighted with this,
   claiming his subconscious was uncontrollably ethical,
   and adamantly refused to fix it.

   After Mel had left the company for greener pa$ture$,
   the Big Boss asked me to look at the code
   and see if I could find the test and reverse it.
   Somewhat reluctantly, I agreed to look.
   Tracking Mel's code was a real adventure.

   I have often felt that programming is an art form,
   whose real value can only be appreciated
   by another versed in the same arcane art;
   there are lovely gems and brilliant coups
   hidden from human view and admiration, sometimes forever,
   by the very nature of the process.
   You can learn a lot about an individual
   just by reading through his code,
   even in hexadecimal.
   Mel was, I think, an unsung genius.

   Perhaps my greatest shock came
   when I found an innocent loop that had no test in it.
   No test. None.

   Common sense said it had to be a closed loop,
   where the program would circle, forever, endlessly.
   Program control passed right through it, however,
   and safely out the other side.
   It took me two weeks to figure it out.

   The RPC-4000 computer had a really modern facility
   called an index register.
   It allowed the programmer to write a program loop
   that used an indexed instruction inside;
   each time through,
   the number in the index register
   was added to the address of that instruction,
   so it would refer
   to the next datum in a series.
   He had only to increment the index register
   each time through.
   Mel never used it.

   Instead, he would pull the instruction into a machine register,
   add one to its address,
   and store it back.
   He would then execute the modified instruction
   right from the register.
   The loop was written so this additional execution time
   was taken into account ---
   just as this instruction finished,
   the next one was right under the drum's read head,
   ready to go.
   But the loop had no test in it.

   The vital clue came when I noticed
   the index register bit,
   the bit that lay between the address
   and the operation code in the instruction word,
   was turned on ---
   yet Mel never used the index register,
   leaving it zero all the time.
   When the light went on it nearly blinded me.

   He had located the data he was working on
   near the top of memory ---
   the largest locations the instructions could address ---
   so, after the last datum was handled,
   incrementing the instruction address
   would make it overflow.
   The carry would add one to the
   operation code, changing it to the next one in the instruction set:
   a jump instruction.
   Sure enough, the next program instruction was
   in address location zero,
   and the program went happily on its way.

   I haven't kept in touch with Mel,
   so I don't know if he ever gave in to the flood of
   change that has washed over programming techniques
   since those long-gone days.
   I like to think he didn't.
   In any event,
   I was impressed enough that I quit looking for the
   offending test,
   telling the Big Boss I couldn't find it.
   He didn't seem surprised.

   When I left the company,
   the blackjack program would still cheat
   if you turned on the right sense switch,
   and I think that's how it should be.
   I didn't feel comfortable
   hacking up the code of a Real Programmer.

This is one of hackerdom's great heroic epics, free verse or no.  In a few
spare images it captures more about the esthetics and psychology of hacking
than all the scholarly volumes on the subject put together.  For an opposing
point of view, see the entry for real programmer.

[1992 postscript --- the author writes: "The original submission to the net was
not in free verse, nor any approximation to it --- it was straight prose style,
in non-justified paragraphs.  In bouncing around the net it apparently got
modified into the 'free verse' form you printed.  In other words, it got hacked
on the net.  That seems appropriate, somehow."]


ΓòÉΓòÉΓòÉ 2. Appendix B: A Portrait of J. Random Hacker ΓòÉΓòÉΓòÉ

This profile reflects detailed comments on an earlier 'trial balloon' version
from about a hundred USENET respondents.  Where comparatives are used, the
implicit 'other' is a randomly selected segment of the non-hacker population of
the same size as hackerdom.

An important point: Except in some relatively minor respects such as slang
vocabulary, hackers don't get to be the way they are by imitating each other.
Rather, it seems to be the case that the combination of personality traits that
makes a hacker so conditions one's outlook on life that one tends to end up
being like other hackers whether one wants to or not (much as bizarrely
detailed similarities in behavior and preferences are found in genetic twins
raised separately).


ΓòÉΓòÉΓòÉ 2.1. General Appearance ΓòÉΓòÉΓòÉ

Intelligent.  Scruffy.  Intense.  Abstracted.  Surprisingly for a sedentary
profession, more hackers run to skinny than fat; both extremes are more common
than elsewhere.  Tans are rare.


ΓòÉΓòÉΓòÉ 2.2. Dress ΓòÉΓòÉΓòÉ

Casual, vaguely post-hippie; T-shirts, jeans, running shoes, Birkenstocks (or
bare feet).  Long hair, beards, and moustaches are common.  High incidence of
tie-dye and intellectual or humorous 'slogan' T-shirts (only rarely computer
related; that would be too obvious).

A substantial minority prefers 'outdoorsy' clothing --- hiking boots ("in case
a mountain should suddenly spring up in the machine room", as one famous parody
put it), khakis, lumberjack or chamois shirts, and the like.

Very few actually fit the 'National Lampoon' Nerd stereotype, though it lingers
on at MIT and may have been more common before 1975.  These days, backpacks are
more common than briefcases, and the hacker 'look' is more whole-earth than
whole-polyester.

Hackers dress for comfort, function, and minimal maintenance hassles rather
than for appearance (some, perhaps unfortunately, take this to extremes and
neglect personal hygiene).  They have a very low tolerance of suits and other
'business' attire; in fact, it is not uncommon for hackers to quit a job rather
than conform to a dress code.

Female hackers almost never wear visible makeup, and many use none at all.


ΓòÉΓòÉΓòÉ 2.3. Reading Habits ΓòÉΓòÉΓòÉ

Omnivorous, but usually includes lots of science and science fiction. The
typical hacker household might subscribe to 'Analog', 'Scientific American',
'Co-Evolution Quarterly', and 'Smithsonian'.  Hackers often have a reading
range that astonishes liberal arts people but tend not to talk about it as
much.  Many hackers spend as much of their spare time reading as the average
American burns up watching TV, and often keep shelves and shelves of
well-thumbed books in their homes.


ΓòÉΓòÉΓòÉ 2.4. Other Interests ΓòÉΓòÉΓòÉ

Some hobbies are widely shared and recognized as going with the culture:
science fiction, music, medievalism, chess, go, backgammon, wargames, and
intellectual games of all kinds.  (Role-playing games such as Dungeons and
Dragons used to be extremely popular among hackers but they lost a bit of their
luster as they moved into the mainstream and became heavily commercialized.)
Logic puzzles.  Ham radio.  Other interests that seem to correlate less
strongly but positively with hackerdom include linguistics and theater teching.


ΓòÉΓòÉΓòÉ 2.5. Physical Activity and Sports ΓòÉΓòÉΓòÉ

Many (perhaps even most) hackers don't follow or do sports at all and are
determinedly anti-physical.  Among those who do, interest in spectator sports
is low to non-existent; sports are something one does, not something one
watches on TV.

Further, hackers avoid most team sports like the plague (volleyball is a
notable exception, perhaps because it's non-contact and relatively friendly).
Hacker sports are almost always primarily self-competitive ones involving
concentration, stamina, and micromotor skills: martial arts, bicycling, auto
racing, kite flying, hiking, rock climbing, aviation, target-shooting, sailing,
caving, juggling, skiing, skating (ice and roller).  Hackers' delight in
techno-toys also tends to draw them towards hobbies with nifty complicated
equipment that they can tinker with.


ΓòÉΓòÉΓòÉ 2.6. Education ΓòÉΓòÉΓòÉ

Nearly all hackers past their teens are either college-degreed or self-educated
to an equivalent level.  The self-taught hacker is often considered (at least
by other hackers) to be better-motivated, and may be more respected, than his
school-shaped counterpart.  Academic areas from which people often gravitate
into hackerdom include (besides the obvious computer science and electrical
engineering) physics, mathematics, linguistics, and philosophy.


ΓòÉΓòÉΓòÉ 2.7. Things Hackers Detest and Avoid ΓòÉΓòÉΓòÉ

IBM mainframes.  Smurfs, Ewoks, and other forms of offensive cuteness.
Bureaucracies.  Stupid people.  Easy listening music.  Television (except for
cartoons, movies, the old "Star Trek", and the new "Simpsons").  Business
suits.  Dishonesty.  Incompetence. Boredom.  COBOL. BASIC.  Character-based
menu interfaces.


ΓòÉΓòÉΓòÉ 2.8. Food ΓòÉΓòÉΓòÉ

Ethnic.  Spicy.  Oriental, esp. Chinese and most esp. Szechuan, Hunan, and
Mandarin (hackers consider Cantonese vaguely dВclassВ).  Hackers prefer the
exotic; for example, the Japanese-food fans among them will eat with gusto such
delicacies as fugu (poisonous pufferfish) and whale. Thai food has experienced
flurries of popularity.  Where available, high-quality Jewish delicatessen food
is much esteemed.  A visible minority of Southwestern and Pacific Coast hackers
prefers Mexican.

For those all-night hacks, pizza and microwaved burritos are big.
Interestingly, though the mainstream culture has tended to think of hackers as
incorrigible junk-food junkies, many have at least mildly health-foodist
attitudes and are fairly discriminating about what they eat.  This may be
generational; anecdotal evidence suggests that the stereotype was more on the
mark 10--15 years ago.


ΓòÉΓòÉΓòÉ 2.9. Politics ΓòÉΓòÉΓòÉ

Vaguely left of center, except for the strong libertarian contingent which
rejects conventional left-right politics entirely.  The only safe
generalization is that hackers tend to be rather anti-authoritarian; thus, both
conventional conservatism and 'hard' leftism are rare. Hackers are far more
likely than most non-hackers to either (a) be aggressively apolitical or (b)
entertain peculiar or idiosyncratic political ideas and actually try to live by
them day-to-day.


ΓòÉΓòÉΓòÉ 2.10. Gender and Ethnicity ΓòÉΓòÉΓòÉ

Hackerdom is still predominantly male.  However, the percentage of women is
clearly higher than the low-single-digit range typical for technical
professions, and female hackers are generally respected and dealt with as
equals.

In the U.S., hackerdom is predominantly Caucasian with strong minorities of
Jews (East Coast) and Orientals (West Coast).  The Jewish contingent has
exerted a particularly pervasive cultural influence (see Food, above, and note
that several common jargon terms are obviously mutated Yiddish).

The ethnic distribution of hackers is understood by them to be a function of
which ethnic groups tend to seek and value education. Racial and ethnic
prejudice is notably uncommon and tends to be met with freezing contempt.

When asked, hackers often ascribe their culture's gender- and color-blindness
to a positive effect of text-only network channels.


ΓòÉΓòÉΓòÉ 2.11. Religion ΓòÉΓòÉΓòÉ

Agnostic.  Atheist.  Non-observant Jewish.  Neo-pagan.  Very commonly, three or
more of these are combined in the same person.  Conventional faith-holding
Christianity is rare though not unknown.

Even hackers who identify with a religious affiliation tend to be relaxed about
it, hostile to organized religion in general and all forms of religious bigotry
in particular.  Many enjoy 'parody' religions such as Discordianism and the
Church of the SubGenius.

Also, many hackers are influenced to varying degrees by Zen Buddhism or (less
commonly) Taoism, and blend them easily with their 'native' religions.

There is a definite strain of mystical, almost Gnostic sensibility that shows
up even among those hackers not actively involved with neo-paganism,
Discordianism, or Zen.  Hacker folklore that pays homage to 'wizards' and
speaks of incantations and demons has too much psychological truthfulness about
it to be entirely a joke.


ΓòÉΓòÉΓòÉ 2.12. Ceremonial Chemicals ΓòÉΓòÉΓòÉ

Most hackers don't smoke tobacco, and use alcohol in moderation if at all
(though there is a visible contingent of exotic-beer fanciers, and a few
hackers are serious oenophiles).  Limited use of non-addictive psychedelic
drugs, such as cannabis, LSD, psilocybin, and nitrous oxide, etc., used to be
relatively common and is still regarded with more tolerance than in the
mainstream culture.  Use of 'downers' and opiates, on the other hand, appears
to be particularly rare; hackers seem in general to dislike drugs that 'dumb
them down'.  On the third hand, many hackers regularly wire up on caffeine
and/or sugar for all-night hacking runs.


ΓòÉΓòÉΓòÉ 2.13. Communication Style ΓòÉΓòÉΓòÉ

See the discussions of speech and writing styles near the beginning of this
File.  Though hackers often have poor person-to-person communication skills,
they are as a rule extremely sensitive to nuances of language and very precise
in their use of it.  They are often better at writing than at speaking.


ΓòÉΓòÉΓòÉ 2.14. Geographical Distribution ΓòÉΓòÉΓòÉ

In the United States, hackerdom revolves on a Bay Area-to-Boston axis; about
half of the hard core seems to live within a hundred miles of Cambridge
(Massachusetts) or Berkeley (California), although there are significant
contingents in Los Angeles, in the Pacific Northwest, and around Washington DC.
Hackers tend to cluster around large cities, especially 'university towns' such
as the Raleigh-Durham area in North Carolina or Princeton, New Jersey (this may
simply reflect the fact that many are students or ex-students living near their
alma maters).


ΓòÉΓòÉΓòÉ 2.15. Sexual Habits ΓòÉΓòÉΓòÉ

Hackerdom tolerates a much wider range of sexual and lifestyle variation than
the mainstream culture.  It includes a relatively large gay and bi contingent.
Hackers are somewhat more likely to live in polygynous or polyandrous
relationships, practice open marriage, or live in communes or group houses.  In
this, as in general appearance, hackerdom semi-consciously maintains
'counterculture' values.


ΓòÉΓòÉΓòÉ 2.16. Personality Characteristics ΓòÉΓòÉΓòÉ

The most obvious common 'personality' characteristics of hackers are high
intelligence, consuming curiosity, and facility with intellectual abstractions.
Also, most hackers are 'neophiles', stimulated by and appreciative of novelty
(especially intellectual novelty).  Most are also relatively individualistic
and anti-conformist.

Although high general intelligence is common among hackers, it is not the sine
qua non one might expect.  Another trait is probably even more important: the
ability to mentally absorb, retain, and reference large amounts of
'meaningless' detail, trusting to later experience to give it context and
meaning.  A person of merely average analytical intelligence who has this trait
can become an effective hacker, but a creative genius who lacks it will swiftly
find himself outdistanced by people who routinely upload the contents of thick
reference manuals into their brains.  [During the production of the book
version of this document, for example, I learned most of the rather complex
typesetting language TeX over about four working days, mainly by inhaling
Knuth's 477-page manual.  My editor's flabbergasted reaction to this genuinely
surprised me, because years of associating with hackers have conditioned me to
consider such performances routine and to be expected. --- ESR]

Contrary to stereotype, hackers are not usually intellectually narrow; they
tend to be interested in any subject that can provide mental stimulation, and
can often discourse knowledgeably and even interestingly on any number of
obscure subjects --- if you can get them to talk at all, as opposed to, say,
going back to their hacking.

It is noticeable (and contrary to many outsiders' expectations) that the better
a hacker is at hacking, the more likely he or she is to have outside interests
at which he or she is more than merely competent.

Hackers are 'control freaks' in a way that has nothing to do with the usual
coercive or authoritarian connotations of the term.  In the same way that
children delight in making model trains go forward and back by moving a switch,
hackers love making complicated things like computers do nifty stuff for them.
But it has to be their nifty stuff. They don't like tedium, nondeterminism, or
most of the fussy, boring, ill-defined little  tasks that go with maintaining a
normal existence. Accordingly, they tend to be careful and orderly in their
intellectual lives and chaotic elsewhere.  Their code will be beautiful, even
if their desks are buried in 3 feet of crap.

Hackers are generally only very weakly motivated by conventional rewards such
as social approval or money.  They tend to be attracted by challenges and
excited by interesting toys, and to judge the interest of work or other
activities in terms of the challenges offered and the toys they get to play
with.

In terms of Myers-Briggs and equivalent psychometric systems, hackerdom appears
to concentrate the relatively rare INTJ and INTP types; that is, introverted,
intuitive, and thinker types (as opposed to the extroverted-sensate
personalities that predominate in the mainstream culture).  ENT[JP] types are
also concentrated among hackers but are in a minority.


ΓòÉΓòÉΓòÉ 2.17. Weaknesses of the Hacker Personality ΓòÉΓòÉΓòÉ

Hackers have relatively little ability to identify emotionally with other
people.  This may be because hackers generally aren't much like 'other people'.
Unsurprisingly, hackers also tend towards self-absorption, intellectual
arrogance, and impatience with people and tasks perceived to be wasting their
time.

As cynical as hackers sometimes wax about the amount of idiocy in the world,
they tend by reflex to assume that everyone is as rational, 'cool', and
imaginative as they consider themselves.  This bias often contributes to
weakness in communication skills.  Hackers tend to be especially poor at
confrontation and negotiation.

As a result of all the above traits, many hackers have difficulty maintaining
stable relationships.  At worst, they can produce the classic computer geek:
withdrawn, relationally incompetent, sexually frustrated, and desperately
unhappy when not submerged in his or her craft.  Fortunately, this extreme is
far less common than mainstream folklore paints it --- but almost all hackers
will recognize something of themselves in the unflattering paragraphs above.

Hackers are often monumentally disorganized and sloppy about dealing with the
physical world.  Bills don't get paid on time, clutter piles up to incredible
heights in homes and offices, and minor maintenance tasks get deferred
indefinitely.

The sort of person who uses phrases like 'incompletely socialized' usually
thinks hackers are.  Hackers regard such people with contempt when they notice
them at all.


ΓòÉΓòÉΓòÉ 2.18. Miscellaneous ΓòÉΓòÉΓòÉ

Hackers are more likely to have cats than dogs (in fact, it is widely grokked
that cats have the hacker nature).  Many drive incredibly decrepit heaps and
forget to wash them; richer ones drive spiffy Porsches and RX-7s and then
forget to have them washed.  Almost all hackers have terribly bad handwriting,
and often fall into the habit of block-printing everything like junior
draftsmen.


ΓòÉΓòÉΓòÉ 3. Appendix C: Bibliography ΓòÉΓòÉΓòÉ

Here are some other books you can read to help you understand the hacker
mindset.


═══ 3.1. GФdel, Escher, Bach ═══

GФdel, Escher, Bach An Eternal Golden Braid: Douglas Hofstadter Basic Books,
1979 ISBN 0-394-74502-7

This book reads like an intellectual Grand Tour of hacker preoccupations.
Music, mathematical logic, programming, speculations on the nature of
intelligence, biology, and Zen are woven into a brilliant tapestry themed on
the concept of encoded self-reference.  The perfect left-brain companion to
'Illuminatus'.


ΓòÉΓòÉΓòÉ 3.2. Illuminatus! ΓòÉΓòÉΓòÉ

Illuminatus!

  I.  'The Eye in the Pyramid'
  II.  'The Golden Apple'
  III. 'Leviathan'.

Robert Shea and Robert Anton Wilson Dell, 1988 ISBN 0-440-53981-1

This work of alleged fiction is an incredible berserko-surrealist rollercoaster
of world-girdling conspiracies, intelligent dolphins, the fall of Atlantis, who
really killed JFK, sex, drugs, rock'n'roll, and the Cosmic Giggle Factor.
First published in three volumes, but there is now a one-volume trade
paperback, carried by most chain bookstores under SF.  The perfect right-brain
companion to Hofstadter's 'GФdel, Escher, Bach'.  See Eris, Discordianism,
random numbers, Church Of The SubGenius.


ΓòÉΓòÉΓòÉ 3.3. The Hitchhiker's Guide to the Galaxy ΓòÉΓòÉΓòÉ

The Hitchhiker's Guide to the Galaxy Douglas Adams Pocket Books, 1981 ISBN
0-671-46149-4

This 'Monty Python in Space' spoof of SF genre traditions has been popular
among hackers ever since the original British radio show.  Read it if only to
learn about Vogons (see bogon) and the significance of the number 42 (see
random numbers) --- and why the winningest chess program of 1990 was called
'Deep Thought'.


ΓòÉΓòÉΓòÉ 3.4. The Tao of Programming ΓòÉΓòÉΓòÉ

The Tao of Programming James Geoffrey Infobooks, 1987 ISBN 0-931137-07-1

This gentle, funny spoof of the 'Tao Te Ching' contains much that is
illuminating about the hacker way of thought.  "When you have learned to snatch
the error code from the trap frame, it will be time for you to leave."


ΓòÉΓòÉΓòÉ 3.5. Hackers ΓòÉΓòÉΓòÉ

Hackers Steven Levy Anchor/Doubleday 1984 ISBN 0-385-19195-2

Levy's book is at its best in describing the early MIT hackers at the Model
Railroad Club and the early days of the microcomputer revolution. He never
understood UNIX or the networks, though, and his enshrinement of Richard
Stallman as "the last true hacker" turns out (thankfully) to have been quite
misleading.  Numerous minor factual errors also mar the text; for example,
Levy's claim that the original Jargon File derived from the TMRC Dictionary
(the File originated at Stanford and was brought to MIT in 1976; the co-authors
of the first edition had never seen the dictionary in question).  There are
also numerous misspellings in the book that inflame the passions of old-timers;
as Dan Murphy, the author of TECO, once said: "You would have thought he'd take
the trouble to spell the name of a winning editor right."  Nevertheless, this
remains a useful and stimulating book that captures the feel of several
important hackish subcultures.


ΓòÉΓòÉΓòÉ 3.6. The Devil's DP Dictionary ΓòÉΓòÉΓòÉ

The Devil's DP Dictionary Stan Kelly-Bootle McGraw-Hill, 1981 ISBN
0-07-034022-6

This pastiche of Ambrose Bierce's famous work is similar in format to the
Jargon File (and quotes several entries from jargon-1) but somewhat different
in tone and intent.  It is more satirical and less anthropological, and is
largely a product of the author's literate and quirky imagination.  For
example, it defines 'computer science' as "a study akin to numerology and
astrology, but lacking the precision of the former and the success of the
latter" and "the boring art of coping with a large number of trivialities."


ΓòÉΓòÉΓòÉ 3.7. The Devouring Fungus ΓòÉΓòÉΓòÉ

The Devouring Fungus Tales from the Computer Age: Karla Jennings Norton, 1990
ISBN 0-393-30732-8

The author of this pioneering compendium knits together a great deal of
computer- and hacker-related folklore with good writing and a few well-chosen
cartoons.  She has a keen eye for the human aspects of the lore and is very
good at illuminating the psychology and evolution of hackerdom.  Unfortunately,
a number of small errors and awkwardnesses suggest that she didn't have the
final manuscript checked over by a native speaker; the glossary in the back is
particularly embarrassing, and at least one classic tale (the Magic Switch
story, retold here under Two Stories About 'Magic' in appendix A) is given in
incomplete and badly mangled form.  Nevertheless, this book is a win overall
and can be enjoyed by hacker and non-hacker alike.


ΓòÉΓòÉΓòÉ 3.8. The Soul of a New Machine ΓòÉΓòÉΓòÉ

The Soul of a New Machine Tracy Kidder Little, Brown, 1981 (paperback: Avon,
1982 ISBN 0-380-59931-7)

This book (a 1982 Pulitzer Prize winner) documents the adventure of the design
of a new Data General computer, the Eclipse.  It is an amazingly well-done
portrait of the hacker mindset --- although largely the hardware hacker ---
done by a complete outsider.  It is a bit thin in spots, but with enough
technical information to be entertaining to the serious hacker while providing
non-technical people a view of what day-to-day life can be like --- the fun,
the excitement, the disasters. During one period, when the microcode and logic
were glitching at the nanosecond level, one of the overworked engineers
departed the company, leaving behind a note on his terminal as his letter of
resignation: "I am going to a commune in Vermont and will deal with no unit of
time shorter than a season."


ΓòÉΓòÉΓòÉ 3.9. Life with UNIX ΓòÉΓòÉΓòÉ

Life with UNIX a Guide for Everyone: Don Libes and Sandy Ressler Prentice-Hall,
1989 ISBN 0-13-536657-7

The authors of this book set out to tell you all the things about UNIX that
tutorials and technical books won't.  The result is gossipy, funny,
opinionated, downright weird in spots, and invaluable.  Along the way they
expose you to enough of UNIX's history, folklore and humor to qualify as a
first-class source for these things.  Because so much of today's hackerdom is
involved with UNIX, this in turn illuminates many of its in-jokes and
preoccupations.


ΓòÉΓòÉΓòÉ 3.10. True Names ... and Other Dangers ΓòÉΓòÉΓòÉ

True Names ... and Other Dangers Vernor Vinge Baen Books, 1987 ISBN
0-671-65363-6

Hacker demigod Richard Stallman believes the title story of this book
"expresses the spirit of hacking best".  This may well be true; it's certainly
difficult to recall a better job.  The other stories in this collection are
also fine work by an author who is perhaps one of today's very best
practitioners of hard SF.


ΓòÉΓòÉΓòÉ 3.11. Cyberpunk ΓòÉΓòÉΓòÉ

Cyberpunk Outlaws and Hackers on the Computer Frontier: Katie Hafner & John
Markoff Simon & Schuster 1991 ISBN 0-671-68322-5

This book gathers narratives about the careers of three notorious crackers into
a clear-eyed but sympathetic portrait of hackerdom's dark side.  The principals
are Kevin Mitnick, "Pengo" and "Hagbard" of the Chaos Computer Club, and Robert
T. Morris (see RTM.  Markoff and Hafner focus as much on their psychologies and
motivations as on the details of their exploits, but don't slight the former.
The result is a balanced and fascinating account, particularly useful when read
immediately before or after Cliff Stoll's The Cuckoo's Egg.  It is especially
instructive to compare RTM, a true hacker who blundered, with the sociopathic
phone-freak Mitnick and the alienated, drug-addled crackers who made the Chaos
Club notorious.  The gulf between wizard and wannabee has seldom been made more
obvious.


ΓòÉΓòÉΓòÉ 3.12. Technobabble ΓòÉΓòÉΓòÉ

Technobabble John Barry MIT Press 1991 ISBN 0-262-02333-4

Barry's book takes a critical and humorous look at the 'technobabble' of
acronyms, neologisms, hyperbole, and metaphor spawned by the computer industry.
Though he discusses some of the same mechanisms of jargon formation that occur
in hackish, most of what he chronicles is actually suit-speak --- the
obfuscatory language of press releases, marketroids, and Silicon Valley CEOs
rather than the playful jargon of hackers (most of whom wouldn't be caught dead
uttering the kind of pompous, passive-voiced word salad he deplores).


ΓòÉΓòÉΓòÉ 3.13. The Cuckoo's Egg ΓòÉΓòÉΓòÉ

The Cuckoo's Egg Clifford Stoll Doubleday 1989 ISBN 0-385-24946-2

Clifford Stoll's absorbing tale of how he tracked Markus Hess and the Chaos
Club cracking ring nicely illustrates the difference between 'hacker' and
'cracker'.  Stoll's portrait of himself, his lady Martha, and his friends at
Berkeley and on the Internet paints a marvelously vivid picture of how hackers
and the people around them like to live and what they think.