That kind of notation, called SCCS/RCS, is the equivalent of finding a rotary phone in a modern office. Nobody uses it in 2005 Windows kernel code unless their programming background goes back decades, to government and military computing environments
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The astrophysics lab I worked at in 2006 was still using svn and had a bunch of Fortran with references to systems from the 70s and 80s. The code ran perfectly well thanks to modern optimizing compilers and having moved from Vax to Linux in the 90s, it was a surprisingly seamless transition.
It reminds me of a conference talk I’ve referenced before “do over or make due” basically implying rewriting large amounts of mostly functioning code was not worth the effort if it could be taped together with modern tools.
PoignardAzurtoday at 8:45 AM
That article is sobering. The fact that this malware stayed under the radar for 20 years is pretty ominous in itself.
ronin_nirontoday at 9:38 AM
IEEE-754 only mandates correct rounding for +-*/ and sqrt. Transcendentals (sin/cos/exp/log/pow) are explicitly allowed to vary in the last few ULPs, and glibc, musl, MSVC, and Intel SVML all do. PID is just basic ops, so libm divergence doesn't hit there, but motor vector control or sensor linearization touches these functions every cycle and small disagreements compound. Two firmware revisions can have zero source diff and still drift in production. The only thing that changed was the linked libm. It actually shows up in Payne-Hanek argument reduction and at the worst table-maker's-dilemma boundaries. Probably why safety-critical guidance pins a specific libm build instead of just "IEEE-754 compliant".
This is an amazing find. I'm very curious regarding the specific targets of these rules, and in the exact changes to the results. Wonder if they will only make a difference in simulated conditions super specific to nuclear reactors?
Lihh27yesterday at 11:03 PM
heh the key move is the worm. you can't catch it by checking on a second box because there is no clean box.
trebligdivadyesterday at 9:06 PM
Haha it's a fun finding though; The source control comment feels a little off; I'm sure there were SCCS (hmm or did cvs use similar?) still around at that time.
deletedyesterday at 9:23 PM
kittikittiyesterday at 11:12 PM
Thank you for sharing this. I was recently pushing the limits of precision computing and this illuminated a part of my research. It built on top of largely government funded research, where I found a surprising dearth of available precision frameworks with verification. Perhaps national security interests, as elucidated by the original poster, discourages transparency of methods for arbitrary precision calculations.
slimyesterday at 9:34 PM
sabotaging science must be the most morally corrupt thing you can do as a civilisation