alt Hacker NewsI took an assembler class in college. Before that, I'd been messing around with Core Wars and working my way through Peter Norton's book on assembly. So when an assignment came up, I used self modifying code to solve it. It was the shortest solution, it ran perfectly, and I submitted it.
The next day, the professor caught me in the math department office (my dad worked there) and said she wanted to talk. Once we were in her office, she told me I wasn't allowed to use self modifying code. I pushed back: "Nothing in the assignment said I couldn't, and the output is correct."
The next class, she walked in and announced that self modifying code was no longer allowed on any assignment. Then she handed back the graded work and I'd gotten a 100.
Thinking back on that: about a week and a half ago I asked Antigravity to build a modern GPU version of Core Wars, except with Redcode mapped directly onto the GPU instruction set. I've had some good success and it's more or less working now, though visualizing what's happening at the GPU/Redcode level is much harder.
But before Fable 5 got yanked, I asked it to "fix" the project and it refused, flipping straight to Opus 4.8. Every single request I sent triggered the fallback. I spent over an hour trying different angles, and I even turned Antigravity loose on automatic so it was the one talking to Fable 5 same result. Every exchange tripped the fallback to 4.8. I wish I'd recorded it.
I also tried a variety of direct requests in a fresh directory "build simple self modifying assembler code" or just "self modifying assembler" and it would switch to 4.8 immediately. It was almost laughable.
There's ZERO credibility to any of these stories right now. If Anthropic really sent something over to this security person, and it's what she says it is, then why on earth didn't they just blog about it?
Hubris is a thing. Companies would do well to remember Steve Jobs in the early Apple days: ship early, ship often, and above all take responsibility for what you ship even when it's broken. Code, hardware, the whole kit all of it can be fixed. Trust is much harder to repair. Anthropic has lost mine, and while I may use them from time to time, it'll be in limited ways.
Self modifying has some sneaky failure modes with modern CPUs. The modification can't be too close to it's execution or it's possible to execute the old version. And it's a nightmare to debug. I have no problem with a teacher prohibiting it. That being said, it should be understood because sometimes you don't get a choice. Borland Pascal 200mhz bug, an initializer in the library would crash. You either don't use that part of the library at all, or you put something ahead of it in the initialization that will find and overwrite the bug. (The root cause was the library calibrating the number of times to spin it's wheels to get a 1 millisecond delay. CPUs above 200mhz would cause this to produce a divide underflow.)