aap_

This is oriented towards Multics. As i understand it GCOS is heavily encumbered with license issues so it's pretty much inaccessible.

Didn't see the reply this late, hopefully you will see mine.

He did indeed use quaternions but it's not easy to find: https://archive.org/details/atreatiseonelec02maxwgoog/page/2...

Unfortunately these equations are not quite without mistakes (I remember a missing dot for a time derivative) compared to the component form. They're correct in the wikipedia article: https://en.wikipedia.org/wiki/History_of_Maxwell's_equations...

If you replace S.∇ with ∇· and V.∇ with ∇× you essentially get the vector calculus version of the equations.

Thank you for extracting the core ideas out of this lengthy text. But I'm still wondering where this very concise present-day formulation with just 4 equations was first written down, even if you can somehow find them scattered around in the book. I found something about Hertz but didn't try to follow up on it, i think he may have only considered a vacuum.

I much prefer AT&T to intel syntax. i concede that cmp has the operand order swapped but otherwise i have to think less about it. Of course it's a matter of taste, but to me at least AT&T just feels nicer.

I've been trying to find these 4 equations in Heaviside's writing but so far have not been successful. He certainly got rid of the quaternions but that seems like a minor difference because Maxwell was also not really taking advantage of them much and always split them up into scalar and vector part.

The major difference I found was that Maxwell was expressing things in terms of the scalar and vector potential (which is what you have to do in QED) whereas Heaviside got rid of that and just had an electric and magnetic field instead. I found that you need 7 of Maxwell's equations to derive the 4 Heaviside(?) equations.

If you actually wanted to embrace quaternions you could write the famous 4 equations as just two (using natural units):

∇E + dB/dt = -ρ

∇B - dE/dt = J

One of the most influential people in computer history. I'm glad I got to exchange a few mails with him a few years ago. RIP, GB.

Funny, this is to a great extent opposite to how I write C.

Sticking to 80 columns and thinking in terms of terminals is exactly opposite of Plan 9 culture though.

Crazy that they would only increase the version number by this little then. version numbers truly mean nothing...

I would assume that with some disassembling 4.01 could be reconstructed from 4.0 without too much trouble.

> Quaternions? Well that's about 4D

Quaternions are about 3D. You need 4 numbers for it, but the space that they operate on is 3D.

Recently got a tour through boston dynamics, but mostly saw the spot department, the atlas department was off limits. I guess this was the reason then :) very cool

I think the 8086 was designed such that 8080 assembly code could be assembled as 8086 machine code. So I'd guess the instruction emulation would probably be reasonably efficient.

Charge is quantized. You cannot have just any amount of electric charge. An electron has three elementary units of negative charge, quarks have -1 and 2. Whether it's a coincidence that proton and electron charge are of the same magnitude (and the neutron is neutral) is another question, but at the elementary level you don't have that much choice for what the charge of a particle is.

Unfortunately he didn't use quaternions in his initial formulation (that was all split into xyz coordinates) and in his later revision he took apart the quaternions into scalar and vectors parts. It could have been so much prettier....but luckily we have geometric algebra for that today.

On the other hand he did derive the electric and magnetic fields from a scalar and potential field. In that sense Heaviside made a step backwards.

The indy kernel is (or was?) the only big endian kernel of 9front, which is a useful thing to have.

The cosmic ballet goes on.

Recently a build from april 1991 showed up: https://betawiki.net/wiki/Windows_NT_3.1_April_1991_build

Not only was it left in the code, it was even changed to allow multiple size levels. gta 3 only has a toggle, two sizes.

The widescreen setting in the menu adjusts 3d rendering (and not even in the best way imaginable), a lot of other things are unaffected by it.

Widescreen support in ps2-era gta leaves things to be desired.

What do you find strange about ASCII?

Another example from the Bourne movie the takes place in Berlin: when he's on his way to Berlin he's not feeling well and has to pull over. But that scene was filmed in Berlin so I found it rather confusing when shortly after the scene he's still on his way and not there yet at all.

The two reasons I don't use postscript directly are lack of alpha blending and no unicode support. Remapping the font to get characters beyond ASCII is too awkward.

I always found it interesting how the 286 and 386 seem to have been designed with Multics in mind. The hardware is not a perfect match, but it's weirdly close.

I don't know much about the Baby, but wikipedia says it had 32 words of memory and 7 instructions. Surely that won't be hard to emulate but will be an absolute pain to use. No wonder it only ran three different programs. There's an emulator here: https://www.davidsharp.com/baby/

Yes, hello there! That was my first whirlwind emulator. The current and third iteration is a very low level one for which I reconstructed the control matrix from around 1954. You can find the code here: https://github.com/aap/blincolnlights/tree/master/whirlwind Unfortunately it currently doesn't run without the little frontpanel i built (blincolnlights 18), but with just a little work that should not be a problem. The only IO device is currently the point plotting display.

The other person interested in Whirlwind I is Guy Fedorkow and his emulator is here: https://github.com/gfedorkow/Whirlwind-Instruction-Simulator...

Whirlwind I is an absolutely cool and lovely machine. I always call it the first microcontroller (not very micro though, took up a whole building).

The PiDP-10 will be available in the near future. I've also been working with him on the PiDP-1, which will hopefully be available soon as well.

I'm not sure XOR/^ was added by Ken himself because it is not in his original B language and while the earliest C compiler can parse it, it can't generate code for it. I think it was Steve Johnson or Dennis Ritchie. Now B originally did have a ^ but that stood for OR because | was in the lower case region of ASCII.

> Go watch the 3-blue-one-brown video on visualizing quaternion rotation, and try to really appreciate how abstract and hard to understand that is

That video was not actually very good unfortunately (surprisingly, I might add). I doubt it helped people understand the matter much but just repeated the old "weird incomprehensible 4d number" story.