╘HIS SECTION IS ABOUT CODED MESSAGES. ╫HEN YOU GET THROUGH IT YOU CAN BE A SPY OR YOU CAN COMMUNICATE WITH ALIEN BEINGS. ┘OU WILL ALSO LEARN ABOUT BINARY AND DECIMAL CONVERSIONS.
┴N INTERESTING USE OF BINARY-DECIMAL CODE CONVERSION IS, WHAT THE TECHNICAL PEOPLE CALL, SERIAL COMMUNICATION. ╚ERE, UNLIKE IN MOST OTHER COMPUTER WORK, WE SEND ONE TINY BIT OF INFORMATION AT A TIME. ╬OT EIGHT, BUT ONE.
╔MAGINE THIS APPLICATION: ONE DAY SOME ALIEN CREATURES MAY WISH TO COMMUNICATE WITH US. ╘HEY AREN'T ABOUT TO STRING EIGHT OR MORE WIRES FROM THE SKY TO YOUR PORCH. ╘HEY'LL HAVE TO TRANSPORT THE BITS USING A GENUINE LASER DEVICE. ╘HEY WON'T BE ABLE TO SEND "╚" OF "HELLO THERE" ALL AT ONE TIME. ╘HEY'LL HAVE TO SEND PIECES OF ╚. ┴ND THEN PIECES OF "E" AND SO ON FOR ALL THE LETTERS OR NUMBERS IN THE MESSAGE. ╘HEY'LL HAVE TO, SOMEHOW, TELL YOU WHEN THEIR MESSAGE BEGINS, WHEN IT ENDS, AND WHEN EACH INDIVIDUAL LETTER BEGINS.
┴LL THIS INFORMATION IS INCLUDED IN THE CODE IN THIS ILLUSTRATION.
// PRG: SECRET LIST //
╬EEDLESS TO SAY, WHETHER YOU'RE RECEIVING INFORMATION, OR SENDING IT, YOU CAN USE THE SAME PROCEDURE. ╠ET'S DO IT.
// PRG: SECRET CODE //
Ç*FP10
*** ╓┴╥╔┴┬╠┼ ╚╔╬╘╙ ***
╨() 8 POWERS OF 2
╙╥ SOUND REGISTER VALUE
─╥ BEEP DURATION
╘$() PATTERNS
═$ MESSAGE
╩ COUNTS LETTERS IN THE MESSAGE
╦ COUNTS BITS IN EACH LETTER
╓ PARITY BIT
*** ╔╬╙╘╥╒├╘╔╧╬╙ ***
╥╒╬ IT. ╘HE SCREEN AND YOUR EARS WILL TELL MUCH OF THE STORY. ╘HE PROGRAM STOPS BY ITSELF. ╘RY CHANGING THE MESSAGE IN ─┴╘┴ LINE IF YOU WISH.
*** ─┼╘┴╔╠╙ ┴╬─ ╨╥╧╩┼├╘╙ ***
╘HIS PROGRAM SENDS THE INFORMATION TO THE SCREEN BY THE SAME PROTOCOL AS IN THE ILLUSTRATION. ╔T DOES IT QUITE SLOWLY, SO YOU CAN WATCH IT. ╔T CAN BE USED TO CHALLENGE YOUR FRIENDS INTO DECODING THE SCREEN OUTPUT, OR FOR YOU TO SEND ANY MESSAGE. ╘URN UP THE VOLUME OF YOUR ╘╓ OR THE MONITOR. ┴LIEN BEEINGS INVARIABLY SEND BEEPING SOUNDS.
╘HE MESSAGE IS CURRENTLY IN A ─┴╘┴ LINE AT THE END. ┘OU CAN CHANGE IT. ┘OU CAN ENCODE IT FURTHER. ╞OR SIMPLICITY, IT'S OUT IN THE OPEN. ╫HEN YOU RUN THE PROGRAM YOU WILL HEAR LOTS OF BEEPS AND SEE PATTERNS OF 1'S, 2'S AND 3'S ON THE SCREEN AS IN THE ATTACHED PICTURE.
╙EVERAL HINTS: ╘HE ALIEN BEINGS SEND MANY SHORT BEEPS TO SIGNAL A BEGINNING AND THE END OF A MESSAGE. ╘HEY SEND LONG, FOLLOWED BY MEDIUM BEEPS, TO SIGNAL A BEGINNING OF A LETTER. ╘HEY LASER-SPLIT EACH LETTER INTO ITS 8 BITS (SEE SECTION ON CONVERSIONS) AND COUNT THE 1-BITS. ╘HEY SIGNAL 0'S AND 1'S WITH A SHORT-MEDIUM AND MEDIUM-SHORT BEEPS, RESPECTIVELY. ╨LAIN, AS DAYLIGHT, RIGHT?. ╦NOWING ALL THIS, AND IF YOU HAVE THE PATIENCE, YOU CAN DECODE ANY PICTURE, AS WELL AS UNDERSTAND HOW THE PROGRAM SENDS THE MESSAGE.
┘OU CAN CHANGE THE PITCH OF SOUND - (VARIABLE ╙╥) AS WELL AS THE LENGTH OF THE BASIC BEEP (VARIABLE ─╥), BOTH EARLY IN THE LISTING.
╔F YOU FEEL LIKE CODING SOMETHING OF YOUR OWN ALONG THESE LINES, TRY TO WRITE ADDITIONAL LINES TO THIS PROGRAM. ╠ET THE NEW CODE UNDO THE FUNNY STUFF INTO A READABLE SEQUENCE OF WORDS. ╘HERE IS A CARRIAGE RETURN CODE BETWEEN PHRASES, IT MIGHT BE NEEDED. ╫ATCH THE DIRECTION OF THE BITS - THEY START AT THE LOW END. ╘HIS SEEMS BACKWARDS TO US.
╔F YOU NEED TO BRUSH UP ON THE BINARY AND DECIMAL NUMBERS, THEY ARE DESCRIBED A LITTLE BIT IN THE SECTION ABOUT NUMBER CONVERSIONS, LATER ON IN THE BOOK.
╔NCIDENTALLY, ONE CONVENIENT THING IS THAT WHEN YOU UNDERSTAND THIS ALIEN SCHEME, EVEN A TINY LITTLE BIT, YOU WILL HAVE LEARNED MORE ABOUT HOW ├OMMODORE CASSETTE TAPES ARE WRITTEN THAN YOU PROBABLY EVER WANTED TO KNOW. ╨ERHAPS IT'S A BUNCH OF USELESS KNOWLEDE, BUT IT CAN BE LOTS OF FUN!
