This talk really puts Mu's accomplishments and failures in context.

Timothy Roscoe, "It's Time for Operating Systems to Rediscover Hardware"

My next step maybe: assemble hardware. Some candidate specs:

• Screen with graphics
• Keyboard
• Persistent storage
• Network
• Touch screen
• Suspend/hibernation

No BIOS/UEFI/Linux/mobile.

Maybe an MNT Reform?

I worry about debugging flow. But Mu had the same problem at the start.

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Images (kinda) and files (kinda) on the Mu computer

The Mu computer has only 256 colors by default, but approximates arbitrary RGB combinations using dithering.

https://archive.org/details/akkartik-mu-2021-07-30 (video; 9 minutes)

Main project page: https://github.com/akkartik/mu

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A little game: guess the result of mixing two colors

Testimonial from 4 year old: this is the best program you've made.

Source: http://akkartik.github.io/mu/html/apps/color-game.mu.html

Main project page: https://github.com/akkartik/mu

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I was just reminded after years of the "weird number" in 2's complement arithmetic:

https://en.wikipedia.org/wiki/Two%27s_complement#Most_negative_number

The reason it came up: it's the result of trying to convert a floating-point Infinity or NaN to an integer.

https://c9x.me/x86/html/file_module_x86_id_61.html

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Color dithering on the Mu computer.

Here is a before/after pair of images. Before has 256x256x256 colors. After has 256 colors.

Before:

After:

Notice all the yellow pixels in the first image that turn into alternating greens and oranges in the second. Also, the stem looks very different. But overall, it looks gratifyingly similar to the original. My eyes took a while before they started to notice differences.

Main project page

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Generalizing dithering to color (assuming a fixed palette) turns out to be surprisingly complex. The r/g/b channels are mostly independent copies each analogous to the greyscale dither, but there's tangling in one place in the center that complicates everything.

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Dithering 256 levels of greyscale using 16 levels of greyscale.

Before:

After:

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Starting to render images on the Mu computer

This screenshot shows a greyscale image dithered using just black and white pixels.

Before:

After:

I rather suspect this isn't quite right. There are some suspicious streaks in various places. Rounding error, maybe.

Credit: https://tannerhelland.com/2012/12/28/dithering-eleven-algorithms-source-code.html. I'm using standard Floyd-Steinberg.

Main project page: https://github.com/akkartik/mu

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Syntax sugar in the Mu shell

I like Lisp. But I also strongly believe anyone should be able to boot into a computer and immediately type in '1+1'. Get started using the computer as just a calculator. It's surprising how few computers satisfy that property. Now the Mu computer does.

https://archive.org/details/akkartik-mu-2021-06-23 (video; 8 minutes)

Main project page: https://github.com/akkartik/mu

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Collaborating on a problem from Advent of Code in Mu

If anybody is into long and rambling 100-minute videos that taper off without a certain conclusion:

https://archive.org/details/2021-06-02-akkartik-sumeet

Mostly by Sumeet Agarwal

Here's the working solution if anyone wants to try it out it: http://akkartik.github.io/mu/html/linux/advent2017/1a.mu.html

Main project page: https://github.com/akkartik/mu

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One idea that got dropped on the editing floor for this post: the long shadows cast over our lives by the very first systems we program on.

I started programming (in undergrad) on an IBM PC descendant running DOS. I moved on to more sophisticated systems, but over a period of decades keep returning to seemingly little things about that first system that I could never replicate. Little things I turn out to be willing to give up big things for.

For others, it was some game console. NES, GBA, etc. I wonder how common it is to actually escape the gravitational pull of our first systems, how much of the differences between our projects stems from having our brains colonized by different first systems.

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