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 for The Story of Mel
From The Free On-line Dictionary of Computing (30 December 2018) :

  The story of Mel, a Real Programmer
  Mel
  Story of Mel
  The story of Mel
  
      A 1983 article by Ed Nather about hacker
     Mel Kaye.  The full text follows.
  
     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
     Corporation, 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">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 its 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-optimised 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 initialiser is optimised", he said proudly) he got
     a Change Request from the sales department.  The program used
     an elegant (optimised) 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 backward, 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."
  
     [Posted to Usenet by its author, Ed Nather , on
     1983-05-21].
  
     Jargon File
     http://www.catb.org/jargon/html/story-of-mel.html)">(http://www.catb.org/jargon/html/story-of-mel.html).
  
     [{On the trail of a Real Programmer
     
  http://www.jamtronix.com/blog/2011/03/25/on-the-trail-of-a-real-programmer/)">(http://www.jamtronix.com/blog/2011/03/25/on-the-trail-of-a-real-programmer/),
     2011-03-25 blog post by "jonno" at Jamtronix]
  
     [When did it happen?  Did Mel use hexadecimal or octal?]
  
     (2003-09-12)
  

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