Safe VSP – 30 year old Commodore 64 bug demystified (2013)

Previously: https://news.ycombinator.com/item?id=5314959

Aswesome :)

"Finally, this phenomenon hinges on the exact timing of the RAS signal at the nanosecond level, and on many machines the critical situation simply doesn't occur. The timing (and thus the probability of a crash) depends on factors such as temperature, VIC revision, parasitic capacitance and resistance of the traces on the motherboard, power supply ripple and interference with other parts of the machine such as the phase of the colour carrier with respect to the dotclock. The latter is assigned randomly at power-on, by the way, which could be the reason why a power-cycle sometimes helps."

Well of course LFT was the one who discovered the reason! His work is impressive. Example: http://www.linusakesson.net/scene/craft/index.php

Reminded me a bit about the modern DRAM issue, i.e., row hammer -- although the details are of course different -- https://en.wikipedia.org/wiki/Row_hammer

Slightly off topic but it's pretty cool to live in a day and age where people can post logic analyzer dumps of hardware processes and debug them together on the internet.

As a neuroscientist, this makes me feel better about this:

https://news.ycombinator.com/item?id=11843376

Shit like this is where I wish we could have a demo scene for modern architecture. (Maybe there is one, and I'm just don't know about it)

I have always fantasized about going back to the bad old days, where you have to boot the computer into the program you want to run.

I dream about having the full capability of modern computing to just run one program. Without any overhead. Without an OS.

It is unfortunate 4164s dates before CAS before RAS refresh. Not all 41256s supports it either I think. There were even SIMMs with labels indicating that they are for Mac Plus/SE only when Apple had to use Siemens chips that don't support it.

One should add '[2013]'.

He should have waited ten more years, then it would have been a 40 year old bug. Much more impressive! ;-P