Next Monday, December 10th, I will be at the Computer History museum to hear a panel discussing the 25th anniversary of the C64. It includes Jack Tramiel, founder and CEO of Commodore, Adam Chowaniec (manager of the Amiga), and some other guy.
There’s a lot that’s been written about retrocomputing, most recently this CNN article. I myself started with a VIC-20 and a 300 baud modem around 1983. I still have a few pages of old homework where I wrote an assembly joystick decoding routine in the margin. I later got a C64c in 1986. My Commodore era ended when I upgrade to a 486DX-33 in 1991. The 486 was my desktop for years, running DOS, Linux, and finally FreeBSD. It then served up root.org until I replaced it in 1999.
The most fascinating things about the C64 were games, demos, and copy protection. Games and demos made me ask “how do they do that?” It was easy to run a disassembler and see surprising techniques like self-modifying code and tricky raster interrupt timing. Copy protection was also a big eye-opener since it seemed to violate the principle that if bits can be read, they can also be written. (Of course, this principle is still generally true, but the skill of the protection author can greatly affect the difficulty.)
I don’t like to admit defeat, and there were some copy protection schemes I was never able to figure out. Now with the power of emulators and ways to physically connect a floppy drive to my PC, I can dust off those old disks and figure out how they worked. Most crackers didn’t need to understand the media layout or protection scheme in detail since they could often “freeze” and capture the game code from memory and then piece together a loader for it. In the race to get the first release of the latest game out, a lot of interesting details about how the protection worked would be overlooked. I think the protection code is as interesting as the game.
There is something refreshing about using a computer where every signal is 5 volts, instructions are a single byte, the clock is 1 microsecond, and ROM gives you reset times of a couple seconds. You just can’t make a mistake and lose all the time spent reinstalling software as you can with today’s hard drive-based systems. Hopefully, the advent of virtualization and good network backup software is going to return us to some of that carefree attitude.
As a hobby, I continue to help with the C64 Preservation Project. My next planned project is creating a USB interface to the parallel cable so that I can use nibtools with my computers that no longer have a printer port. Also, I find that loading an image of a protected floppy into an emulator on my laptop and disassembling it makes for a nice travel diversion during the holidays.
I hope you will enjoy the holidays in your own way and have a great 2008!