John Walker
fourmilab.ch · Personal blog · on HN since 2007
John Walker, Autodesk co-founder, runs Fourmilab, a personal site covering science, software, random number generation, and The Hacker's Diet.
What HN saysCommenters praise it as a fantastic, hand-crafted science site, and cite The Hacker's Diet as a model for simple, documentation-style guides.
447HN people shared it
319linked it in comments
176stories submitted
4.0Kstory points
3 months agolast shared
2007people per year2026
Most-shared posts
- 1The Hacker's Diet (2005)67 people · 219 points · first shared 2007 · 77 comments on HN
- 2HotBits: Genuine random numbers, generated by radioactive decay29 people · 7 points · first shared 2010 · discussion on HN
- 3How big brother and big media can put the Internet genie back in the bottle.21 people · 82 points · first shared 2009 · 32 comments on HN
- 4The Autodesk File (2017)21 people · 53 points · first shared 2007 · 12 comments on HN
- 5The Hacker's Diet17 people · 132 points · first shared 2007 · 53 comments on HN
- 6Sketch of the Analytical Engine, with Notes by Ada Lovelace (1842)14 people · 64 points · first shared 2009 · 5 comments on HN
- 7ENT – A Pseudorandom Number Sequence Test Program12 people · 4 points · first shared 2011 · discussion on HN
- 8The Hacker's Diet11 people · 66 points · first shared 2008 · 85 comments on HN
- 9On the Electrodynamics of Moving Bodies (1905)11 people · 32 points · first shared 2010 · 4 comments on HN
- 10What Gives Gold that Mellow Glow? (2006)10 people · 243 points · first shared 2009 · 23 comments on HN
- 11The Autodesk File10 people · 7 points · first shared 2018 · discussion on HN
- 12Golden Rules for Making Money (1880)9 people · 437 points · first shared 2007 · 180 comments on HN
- 13The Oh My God Particle9 people · 102 points · first shared 2010 · 20 comments on HN
- 14John Walker's history of Autodesk (1994)9 people · 85 points · first shared 2008 · 16 comments on HN
- 15An extraterrestrial message encoded in our DNA (Short Story)8 people · 2 points · first shared 2009 · discussion on HN
What HN people wrote when they linked it
ResNet · 2024-02-08
I think this is the JS tool mentioned: https://bigarrow.tripod.com/js-encr/j4jscrypt.html
His main website is really fantastic, well worth a visit: https://www.fourmilab.ch/
ssivark · 2021-08-24
Great vibe!
To add to the mix: As a teen when I first started frequenting the interwebz, one of my favorite sites was personal website with a lot of great science content, with a very hand-crafted vibe (which continues to this day!): https://fourmilab.ch/
Little did I know that it is the personal website maintained by John Walker, the founder of Autodesk!
It continues to be a pleasure to browse, say, on a lazy Sunday afternoon.
ruevs · 2026-03-31
The last Autodesk software I've used was AutoCAD 2000 (released in 1999). And I've not followed them since.
Perhaps they have indeed become "one of the worst corp. in the world of software", but in the early years they were very interesting. The founder of Autodesk, John Walker (he died in 2024) wrote/edited and interesting book on the early years: "The Autodesk File" https://fourmilab.ch/autofile/
criticas · 2026-02-02
Nice idea, but "small composable programs" includes R scripts? That's great if you're already using R, a bit much to install if you're not.
You could simplify things by cribbing from the Hacker's Diet (https://www.fourmilab.ch/hackdiet/) and using an exponentially weighted moving average as your filter. 10% of today's weight + 90% yesterday's EWMA. That's almost a one-liner in awk or perl, or a simple function in bash.
Copilot suggests:
awk 'BEGIN{alpha=0.1} NF>=2 {
date=$1; w=$2;
if (NR==1) ewma=w; else ewma=alpha*w + (1-alpha)*ewma;
printf "%s\t%g\t%.6f\n", date, w, ewma
}' input.txt
qgin · 2025-11-08
I love this sort of documentation-style guide to medical issues. Reminds me of https://www.fourmilab.ch/hackdiet/e4/
layer8 · 2025-07-30
This is much more complicated than needed. Following the Hacker’s Diet [0] is simple to understand and sufficient, and yes, heed common-sense things like good sleep, some basic exercise, stress reduction, and eating healthy food.
[0] https://www.fourmilab.ch/hackdiet/
emmanueloga_ · 2025-07-24
I'm a fan of the app, one of those rare web apps that have been reliably there for more than 10 years and "just works". Today I found out it has been refreshed and its source released [1].
Congrats Erv Walter for the launch of v2 and thank you for making the app and source available!
For those who haven't seen this before, this is a free web app that makes it easy to chart a moving average of the weight measured with smart scales (Withings/Fitbit), following the ideas on John Walker's "The hacker diet" [2].
--
1: https://github.com/ervwalter/trendweight
2: https://www.fourmilab.ch/hackdiet/
cylinder714 · 2025-02-12
The article references the "Oh-My-God particle, the most energetic particle yet encountered. Here's the late John Walker's excellent piece on that:
https://fourmilab.ch/documents/OhMyGodParticle/
theoa · 2025-01-02
John Walker the founder would grieve as well:
https://en.wikipedia.org/wiki/John_Walker_(programmer)
He was a digital hoarder sharer. See:
https://fourmilab.ch/
shagie · 2024-12-11
From the original https://www.fourmilab.ch/hotbits/how3.html
> To create each random bit, we wait until the first count occurs, then measure the time, T1, until the next. We then wait for a second pair of pulses and measure the interval T2 between them, yielding a pair of durations. If they're the same, we throw away the measurement and try again. Otherwise if T1 is less than T2 we emit a zero bit; if T1 is greater than T2, a one bit. In practice, to avoid any residual bias resulting from non-random systematic errors in the apparatus or measuring process consistently favouring one state, the sense of the comparison between T1 and T2 is reversed for consecutive bits.
somenameforme · 2024-03-29
This was my initial reaction as well, as I have complete disdain for the lowest common denominator approach to many things in modern society. But then something occurred to me - IMO one of the most well written scientific papers is Einstein's special relativity paper. [1] But it's absolutely a 'story mode' paper! A moderately educated individual could easily understand and follow the paper, even if they might not necessarily follow all the math. It just flows inordinately better than most modern papers - most of which are written on comparably simple and evolutionary (rather than revolutionary) topics.
Of course this may be an issue of domain. I'm mostly interested in cosmology/astronomy/physics, where math is a tool rather than the object of the paper itself.
[1] - https://www.fourmilab.ch/etexts/einstein/specrel/specrel.pdf
InitialLastName · 2024-02-29
I've only been using it since I saw it recommended a few weeks ago, but for Hacker's Diet[RIP, 0]-style diet tracking MacroFactor has been unbeatable. Nothing dumb or meaninglessly social, just weight+nutrition tracking. In recognition that humans are imperfect and that both sides of CI/CO are more complicated than is apparent, they have built the system around a "best effort" vibe; systematic bias gets filtered out through feedback (if you regularly underestimate the calories you actually eat, the system will feed back by lowering your limits).
[0] https://www.fourmilab.ch/hackdiet/
jacquesm · 2024-02-08
Oh that sucks... John was instrumental in the success of ww.com, thanks to him we had speakfreely as the audio layer using the GSM encoder.
His 'digital imprimatur' was as prophetic as much as it is still relevant today, well worth reading:
https://www.fourmilab.ch/documents/digital-imprimatur/
fghorow · 2024-02-08
My all-time favorite website is his "Bending Spacetime in the Basement"[1].
RIP John Walker.
[1] https://www.fourmilab.ch/gravitation/foobar/
karbak · 2024-02-08
"We'll Return, After This Message" is one of my all-time favorite short stories: https://www.fourmilab.ch/documents/sftriple/gpic.html
acqq · 2023-12-18
Here a paper can be found about running the "cards" created by Rainer Glaschick based on the program described in Lady Lovelace's Note G on a modified emulator of the Babbage's analytical engine:
https://rclab.de/analyticalengine/lovelace_noteg_paper
And the text by the author of that emulator about the authenticity of the emulator:
https://www.fourmilab.ch/babbage/authentic.html
Note that the sizes of what we would today call "registers" in what we would today call "ALU" were, per 1837 description 40, per 1864 description 50 decimal digits, much bigger than the number of mantissa decimals in common "float" (7) or "double" (15) floating point representations, and the assumption of the engine was to use fixed point decimal arithmetic.
kfrane · 2023-12-14
The only other person I remember doing that is https://en.m.wikipedia.org/wiki/John_Walker_(programmer)
Btw. he published a great read on how they started Autodesk https://www.fourmilab.ch/autofile/e5/
tdeck · 2022-11-15
There's an excellent story about an early mainframe version of this game called ANIMAL that copied itself into a new directory each time it was played:
https://www.fourmilab.ch/documents/univac/animal.html
joeman1000 · 2022-09-05
Anyone interested in this should also check out Rudy Rucker & John Walker’s work on cellular automata [1]. These guys were obsessed with ants, hence ‘fourmi’ labs, fourmi meaning ‘ant’ in French.
Both of these guys have done incredible things. Rucker wrote the Ware tetralogy and Walker owned/engineered AutoCAD.
Rucker also wrote ‘The Hacker and the Ants’ where the protagonist (basically Rudy himself) takes on a virus which manifests as a virtual ant. Really quirky story, well worth reading.
[1]: https://www.fourmilab.ch/cellab/
Animats · 2022-08-22
This is addressed to organizations with large internal IT organizations, where software is not an external product. That's a classic problem.
Thinking of in-house software as a product is not all that useful. It's not a product. It does not have real pricing. You can't sell more of it and increase the customer base. You can't drop money-losing products. Cost centers do not have the same incentive structure as profit centers.
Here's a classic memo on that subject.[1]
[1] https://www.fourmilab.ch/autofile/www/section2_40_3.html
teddyh · 2022-07-25
In 1988, Autodesk (makers of AutoCAD) was so impressed by the Xanadu project that they gave them financial backing, hoping to bring a product to market the following year. After four years without any progress, Autodesk gave up:
> […] Come 1992, the “resources of Autodesk” were still funding “talent of the Xanadu team” which had not, as of that date, produced anything remotely like a production prototype—in fact, nothing as impressive as the 88.1x prototype which existed before Autodesk invested in Xanadu. On August 21, 1992 Autodesk decided to pull the plug and give its interest in Xanadu back to the Xanadudes.
(Quoted from footnote linked from this page: https://www.fourmilab.ch/autofile/e5/chapter2_64.html)
thirtysixred · 2022-07-18
Kind of sounds like the Hackers Diet: https://www.fourmilab.ch/hackdiet/
Alternatively, I have used https://trendweight.com/ for many many years and love its approach.
rootingforyou20 · 2022-05-19
OP, don't know you but rooting for you
Re eating/getting healthier,
1) food: this guy Rip is truly a lifechanger (esp if since you're in the zone when it would be smart to look after your heart: https://mealplanner.plantstrong.com/
2) Lose weight (this approach might be appealing to your engineer'y instinct): https://www.fourmilab.ch/hackdiet/
3) Exercise:
- Warm up (DO THESE): https://www.youtube.com/watch?v=-QWyyHfARNI
- Try to get through a round of this w/ good form + then try to do 2, 3, etc: https://www.youtube.com/watch?v=XTSIqbuZC0Y&t=369s
I don't have any career advice for you, leaving is one option but consider that it would great for you to "skill-up" the people around you so when you leave it isn't like they lost their Golden-Boii, but rather bow out like a Bob Iger at Disney & leave them with a glorious future blah blah
grujicd · 2022-03-08
While you're on fourmilab site, I recommend The Autodesk File ebook:
https://www.fourmilab.ch/autofile/
A story about how Autodesk started. If I recall correctly (read it 15+ years ago), a bunch of programmers got together, without clear idea what they'll build. So they started multiple projects and decided to focus on what gets the most traction. In essence a way to test multiple ideas in paralel, thus increasing their collective chances.
Sharlin · 2022-02-16
> BTW his blog post "Babbage was a true genius" looks great: http://tomforsyth1000.github.io/blog.wiki.html#%5B%5BBabbage%20was%20a…
Highlighting this for extra exposure. For even more info, plus an emulator, see [1] (also linked from the blog post).
[1] https://www.fourmilab.ch/babbage/cards.html
cletus · 2021-07-06
This sounds appealing but there are a couple of major problems.
The first is that you have to get to a significant percentage of light speed for this to manifest itself. Even at 0.95c time is only traveling at 1/3 of normal speed [1].
Second, the energy cost for this is truly mind-boggling. Doing so when you carry the fuel seems highly impractical. The best bet are laser highways [2]. But, you need to build that first.
The upper limit of laser propulsion isn't really high enough for that level of time dilation.
Third, traveling at these speeds makes any potential impact within even a speck of dust potentially fatal.
Lastly, fun fact: such a ship actually needs to be aerodynamic. Why? Above 0.95c the drag of hydrogen atoms in the interstellar medium will start to slow you down.
[1]: https://www.fourmilab.ch/cship/timedial.html
[2]: https://www.youtube.com/watch?v=oDR4AHYRmlk
arcleo · 2020-11-16
Since the comments here seem to have taken a turn of "How to fix obesity"; for anyone reading this article who wants to lose weight I would strongly recommend The Hacker's Diet. Especially if you're a developer or in IT the book may appeal to you as it's written by an IT person who approached weight loss as a technical problem. I lost 70lb in 2 years thanks to this book. The fulltext can be found here:
https://www.fourmilab.ch/hackdiet/
fb03 · 2020-11-13
I recommend reading THE HACKER'S DIET to all my nerdy/hacker friends (like me) who seek to understand and engage in weight loss with some simple truths worded by a deep nerd himself (one of the authors of AutoCAD).
It made sense to me more than what the doctors told me I should blindly do "and it'll work". Things I already knew but just couldn't swallow (<-- nice pun here).
https://www.fourmilab.ch/hackdiet/
mceachen · 2020-09-14
Any stochastic data source may not (and almost certainly isn't) evenly distributed--it'll probably follow some normal distribution.
Your PRNG that reads from your telescope would need to compensate for this.
As far as using radiation to generate random numbers, check out https://www.fourmilab.ch/hotbits/
0zelot · 2020-05-18
yes totally. There is a great DIY project for doing that https://www.fourmilab.ch/hotbits/
It's not required to have the particle energy measured for making random numbers, detecting precisely the arrival time of particles is more important plus having a high hit rate is usually desired. My DIY detectors are not optimized in that way but it would work in principle. Timestamps are already recorded by the python scripts on github, it would be just a matter of evaluating them.