KRAKOWICZS KRACKING KORNER IV

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*************************************** * * * * * KRAKOWICZ'S KRACKING KORNER IV * * * * * * * * * * * * THE ARCADE MACHINE * * * * * * * * WITH NOTES ON NMI AND IDSI'S JUGGLER* * * * * * * *************************************** AFTER A NINE-MONTH DELAY, BR0DERBUND HAS FINALLY RELEASED THE ARCADE MACHINE (A.M.). THE PROTECTION SCHEME IS A NEW CHALLENGE FOR COPIERS, SINCE IT USES THE TECHNIQUE KNOWN AS SPIRALING OR QUARTER-TRACKING, AS WELL AS THE STANDARD BR0DERBUND SYSTEM OF A NEW ADDRESS MARKER FOR EACH TRACK. AN ATTEMPT TO COPY THE DISK WITH A CONVENTIONAL NIBBLE COPIER QUICKLY REVEALS THAT TRACKS 0 AND 3-11 ARE EASILY COPIED WITH AN ADDRESS MARKER OF D5 AA 96, WHILE THE REST OF THE TRACKS ARE A MYSTERY. PROBING INTO THE LOADER REVEALS THE FOLLOWING INFORMATION ABOUT TRACK USAGE: TRACK CONTENTS ----- -------- T0/S0 PRELOADER --> 800-8FF (AS ALWAYS) /S1-5 LOADER --> 300-7FF T1-2 HIRES SPLIT "BR0DERBUND" LOGO AND PROGRAM T12-20 MAIN PROGRAM WHICH LOADS INTO 800-BFFF T12-13.5 FOUR HALFTRACKS USED FOR QUARTER-TRACKING T3-4 #1 SHAPE CREATOR T5-6 #2 PATH CREATOR T7-8 #3 GAME OPTIONS T9-A #4 LEVEL OPTIONS TC-D #5 BKGD/TITLE CREATOR TE-F #6 LOAD/SAVE GAME T10-11 #7 CREATE GAME DISK (OPTION #8 JUMPS TO 0800 TO RUN THE GAME) THE APPROACH TO KRACKING THIS TYPE OF PROGRAM SEEMS STRAIGHTFORWARD:LOAD THE PROGRAM INTO MEMORY, RESET IT, AND SAVE IT OUT TO DISK AS A BINARY FILE, WITH THE APPROPRIATE MEMORY MOVES. HOPEFULLY, YOU'LL LOCATE THE STARTING ADDRESS AND BE ABLE TO RUN THE BINARY FILE AT WILL. IF YOU WISH TO INCLUDE ALL OF THE ADVERTISING FOR BR0DERBUND AT THE BEGINNING, THIS WORKS. IF YOU TRY TO DELETE THE DUAL BANNER, IT CRASHES. THE REASON IS THAT MODULE SWITCHING IS VIA THE STACK--THEY PUSH THE CORRECT LOCATION ONTO THE STACK AND DO AN RTS. SO, UNLESS YOU HAPPEN TO KNOW THE VALUE OF THE PROGRAM COUNTER (THAT IS, EXACTLY WHAT THE ADDRESS WAS WHEN YOU STOPPED), THE STACK POINTER (S) AND THE PROCESSOR STATUS WORD (P), AND RESTORE THEM EXACTLY AS THEY WERE BEFORE THE RESET, THE PROGRAM PROBABLY WON'T RUN. ANYONE WHO TRIED TO BREAK JUGGLER FOUND THIS TO BE FRUSTRATING IN THE EXTREME, SINCE SOMETIMES THE GAME WOULD RUN ALL THE WAY THROUGH THE FIRST LEVEL BEFORE CRASHING - THE SAME TECHNIQUE WAS USED THERE, BUT WITH EVEN MORE PROTECTION. THERE IS A HARD WAY AND AN EASY WAY TO DO EVERYTHING, AND IF YOU ARE COMPLETELY RESTRICTED TO SOFTWARE DEVICES, IT IS STILL POSSIBLE TO BREAK ARCADE MACHINE. REFERRING TO THE NIBBLE ALTERATION TECHNIQUES DESCRIBED IN THE PREVIOUS EPISODE, IT IS POSSIBLE TO LOCATE AND ALTER THE GAME LOADER SO THAT IT HALTS WITH CONDITIONS WELL DEFINED AFTER THE ENTIRE PROGRAM IS IN MEMORY. IF IT IS YOUR PURPOSE IN LIFE TO LEARN AS MUCH AS YOU POSSIBLY CAN ABOUT DISK PROTECTION SCHEMES AND THE CIRCUMVENTION THEREOF (ONLY A FEW REALLY CRAZY PEOPLE ARE SO INCLINED), THIS IS REWARDING. IF YOU ARE INTERESTED IN PREPARING AN UNPROTECTED VERSION OF THE GAME WITH MINUMUM ADVERTISING AND MINIMUM EFFORT, HOWEVER, THERE IS AN EASIER WAY. THIS SOLUTION IS ELEGANT, BUT REQUIRES A VISIT TO THAT GOD OF THE UNDERWORLD =>HARDWARE<=. B PLEASE PLACE ANY NEW KRAKING TIPS OR TECNIQUES ON THE KRACKING BOARD. [\/][\/][\/][\/][\/][\/][\/][\/][\/] USS ENTERPRISE I 318-367-8860

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