4AM is a prolific computer historian whose practice involves cracking the copy protection on neglected Apple ][+ floppy disks, producing not just games, but voluminous logs that reveal the secret history of the cat-and-mouse between crackers and publishers.

4AM's logfile for their crack of the 1982 crack of Burger Time (which I played until my fingers bled, but on a Colecovision, I think) reveals some incredible, subtle trickery that played out within the extremely confined headroom of a 5.25" floppy's limited sectors.

Chapter 1

In Which We Start From Scratch We're starting from bare metal on this

one. My automated tools, they do nothing

for us. Strap in. [S6,D1=original disk] [S6,D2=crack-in-progress (the partial

copy I made with Locksmith Fast Disk

Backup)] [S5,D1=my work disk] ]PR#5

...

]CALL -151 *9600<C600.C6FFM ; copy boot sector (T00,S00) to the

; graphics page so it survives a reboot

96F8- A0 00 LDY #$00

96FA- B9 00 08 LDA $0800,Y

96FD- 99 00 20 STA $2000,Y

9700- C8 INY

9701- D0 F7 BNE $96FA ; turn off slot 6 drive motor

9703- AD E8 C0 LDA $C0E8 ; reboot to my work disk in slot 5

9706- 4C 00 C5 JMP $C500



BurgerTime: A 4am crack, 2015-12-31 [4AM/archive.org]

Apple II Library: The 4am Collection [archive.org]

(via JWZ)