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What Did Ada Lovelace’s Program Actually Do?

twobithistory.org

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Re: What Did Ada Lovelace’s Program Actually Do?

#12
post #9
post #4

Holy shit. I got shivers the moment I realized Sinclair actually finds and fixes a bug from the very first program written in 1843. In her “diagram of development,” Lovelace gives the fourth operation as v5 / v4. But the correct ordering here is v4 / v5. 1843! I was recently at the Musee des arts et metiers in Paris, and they have several original Pascalines on display. So many marvels packed into a very tight space,…

What else would you recommend checking out in Paris by way of museums?

The ossuary, for sure. Louvre is a meh. The park adjacent to the Louvre is good-to-go. Wander between the Louvre and Eiffel, there is a brassiere frequented by diplomats. Pickup intramural football (soccer) by the nurses' college just across the river. Explore on foot with only a rough plan is usually the best way to find treasures.

Re: What Did Ada Lovelace’s Program Actually Do?

#13
post #4

Holy shit. I got shivers the moment I realized Sinclair actually finds and fixes a bug from the very first program written in 1843. In her “diagram of development,” Lovelace gives the fourth operation as v5 / v4. But the correct ordering here is v4 / v5. 1843! I was recently at the Musee des arts et metiers in Paris, and they have several original Pascalines on display. So many marvels packed into a very tight space,…

Is this the first documented instance of finding a bug in a computer program? That should be a more well known milestone in my opinion.

Re: What Did Ada Lovelace’s Program Actually Do?

#15

This is a great article, and I also found myself shuddering to think what would happen if the world ever saw the first program I ever wrote (whatever that was).

For me, that's no big deal: 10 PRINT "HELLO WORLD" Even the horrible crap I wrote as an novice is probably less embarrassing to me that the stuff I wrote as a journeyman who shoulda known better. Thankfully, the most embarrassing things are, like, spending 2 days configuring postfix and not realizing that I could just read the log files and it tells me specifically what isn't working. A valuable lesson, but embarrass…

Hahaha, mine:

    mov ah, 2
    mov dl, 7
    int 21
    int 20
Discovering that I could write my own programs with debug.com was earth shaking. Picked up some decade old book on it at Half Price Books (which went well with my decade old machine -- an 80s model IBM with integrated monochrome green screen) and never looked back.

Re: What Did Ada Lovelace’s Program Actually Do?

#16

> she made groups of operations and in the text of her note specified when they should repeat. Does anyone know what "should repeat" means? Was the machine capable of repeating or does this mean the human operator needed to do the repeating?

You can see the exact 'program' here [1].

It's really just a series of mathematical steps with a store of values in between. Notions that would have clearly taken it from being a series of mathematical steps, to a program, such as branching, looping, or jumping are left completely unspecified. So her 'loop' was specified literally as "here follows a repetition of operations 13-23".

In other words, "should repeat" is left an as exercise to the reader.

[1] - https://i.imgur.com/HSWjbUl.jpg

Re: What Did Ada Lovelace’s Program Actually Do?

#17
post #9
post #4

Holy shit. I got shivers the moment I realized Sinclair actually finds and fixes a bug from the very first program written in 1843. In her “diagram of development,” Lovelace gives the fourth operation as v5 / v4. But the correct ordering here is v4 / v5. 1843! I was recently at the Musee des arts et metiers in Paris, and they have several original Pascalines on display. So many marvels packed into a very tight space,…

What else would you recommend checking out in Paris by way of museums?

The National Museum of Natural History is unlike any other I’ve been to. It is fairly worn out but is great. It is displayed in a very different t format to what I’m used to. https://en.m.wikipedia.org/wiki/National_Museum_of_Natural_H...

Quiet and completely excellent, The Museum of Heritage and Architecture. https://www.unjourdeplusaparis.com/en/paris-culture/musee-ci...

The Army Museum is worth a visit - it is interesting to see a less Anglo centric view of the wars, particularly WW1. The paintings are deeply grim - not ideal if you have young kids. https://en.m.wikipedia.org/wiki/Musée_de_l%27Armée

The Museum of the Middle Ages is currently being renovated but is well regarded. https://en.m.wikipedia.org/wiki/Musée_de_Cluny_–_Musée_natio...

Probably a candidate for best museum in the world, the Louvre is a great way to completely waste a day with massive crowds, sore feet, food and water shortages, closed exhibits, intense heat and even more crowds. Get a map ahead of time and check that the things you want to see aren’t closed before you go.

Re: What Did Ada Lovelace’s Program Actually Do?

#18
post #4

Holy shit. I got shivers the moment I realized Sinclair actually finds and fixes a bug from the very first program written in 1843. In her “diagram of development,” Lovelace gives the fourth operation as v5 / v4. But the correct ordering here is v4 / v5. 1843! I was recently at the Musee des arts et metiers in Paris, and they have several original Pascalines on display. So many marvels packed into a very tight space,…

Is this the first documented instance of finding a bug in a computer program? That should be a more well known milestone in my opinion.

The author mentions that another blogger, Jim Randell, found the same error in 2015 when translating the tables to Python: https://enigmaticcode.wordpress.com/tag/bernoulli-numbers/

It's also debated whether these were bugs from Ada or transcription errors. But, yes, it does seem like an interesting milestone

Re: What Did Ada Lovelace’s Program Actually Do?

#19

> she made groups of operations and in the text of her note specified when they should repeat. Does anyone know what "should repeat" means? Was the machine capable of repeating or does this mean the human operator needed to do the repeating?

The Analytical Engine was Turing complete so loops and conditionals would have been possible, but Babbage didn't get near building it.

The London Science Museum built a fully working Difference Engine, to Victorian tolerances so it could have actually worked.

I heard of a project to build a modern working replica but I don't know if anything ever came of it.

Re: What Did Ada Lovelace’s Program Actually Do?

#20

> she made groups of operations and in the text of her note specified when they should repeat. Does anyone know what "should repeat" means? Was the machine capable of repeating or does this mean the human operator needed to do the repeating?

You can see the exact 'program' here [1]. It's really just a series of mathematical steps with a store of values in between. Notions that would have clearly taken it from being a series of mathematical steps, to a program, such as branching, looping, or jumping are left completely unspecified. So her 'loop' was specified literally as "here follows a repetition of operations 13-23". In other words, "should repeat" is…

It's easy to be dismissive from today's perspective, but I think it adequately conveys the algorithm. As I don't think Babbage ever published an instruction set I'm not sure it could have gone a lot further.
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