[gamache]

> Live Demos

> Don’t do it. Really, don’t do it. Anyone that has been giving tech talks for a while now knows not to do it. Don’t do it.

A few years ago, I found myself in San Francisco right on time to see Larry Wall give a talk announcing the release of Perl 6, and showing off some of its (abundant) features.

Larry Wall did the entire presentation in Vim, including live coding.

It's not that no one can pull this off, it's just that most of us aren't them :)

[hodgesrm]

> It's not that no one can pull this off, it's just that most of us aren't them :

Having just done a talk at FOSDEM 2024 the main reason not to do a demo is that the slots in most devrooms are really short. In the monitoring devroom talks were in 30 minute slots, which included audio setup, talk, questions. Live demos can really enhance a presentation to developers but trying squeeze them into an already short slot can muddy the message. I would rather point the audience to examples they can run themselves.

On a related point, I find recorded demos pretty horrible. The pleasure in demos is seeing the presenter work fluently with technology and the audience at the same time: "the achieve of, the mastery of the thing!" as Gerard Manley Hopkins memorably phrased it. [0] It's showmanship and existence proof combined--and the most powerful rhetorical device to make technical points. The best ones are legend. [1]

[0] https://www.poetryfoundation.org/poems/44402/the-windhover

[1] https://en.wikipedia.org/wiki/The_Mother_of_All_Demos

[bertil]

In the Python world, James Powell is famous for breezing through a combination of vim (the editor) and wat (the tutorial by absurd) with a lot of custom command line tools and even examples that feel at the same time immoral, hilarious, and perfectly crafted. There’s a reason his GitHub handle and his company are called “Don’t use this code.” He’s switched to analytical SQL lately, which is less prone to comedy but still very virtuoso.

[bsder]

> It's not that no one can pull this off, it's just that most of us aren't them :)

The issue is that live demos require INSANE amounts of prep.

You have to go over it. Then you go over it again. Then you go over it again with a stopwatch. Then you go over it again. Then you kill the network and go over it again. Then you go over it again with a stopwatch. Then you go over it with a friend with a stopwatch. Then you go over it again. Then you go over it with a friend but you use the stopwatch with no network. Then you go over it again. Repeat until you feel like you're in Groundhog Day. Then go over it one more time.

By the time you give the demo in front of people, you should be so damn bored with giving it that the only reason you want to give the talk is to see the audience reaction.

[Dalewyn]

And then Windows 95 BSODs and gains more and better publicity than if the show had gone smoothly.

[nestorD]

In my experience (I gave a demo as part of a talk today! It went great!), you want your code to be reliable (obviously... a 1 in 5 failure rate will bite you back on demo day), require as little thinking as possible (that can be worked around with increased automation, but if you automate all the things, you might as well be showing a recording), and rehearse things extensively (this applies to every part of a talk anyway).

[kevincox]

Also rehearse on a specific commit/build. I've seen so many cases where a feature or two were added since rehearsal and about was introduced into the demo path. If you do want to fix something for the demo run through your rehearsal another few times on the new commit.

[reaperman]

David Beazley does a great job with live demos as well. https://www.youtube.com/watch?v=pkCLMl0e_0k

[anitil]

Some of his live demos take my breath away. I have to make notes to myself like "click the 'upload' button" so I don't forget during a presentation. It's like my brain switches to a mode where simple tasks are impossible

[ghaff]

Yeah, there's a certain demo gods category who can usually make it work. But it's also sort of showing off. And I'm also somewhat unconvinced about how much demos add to a presentation a lot of the time.

[stavros]

https://gitlab.com/stavros/itsalive

[librasteve]

Larry is a genius and perl6 (now raku) does indeed abound with features. The idea aiui was to minimize the need for external dependencies in most code bases and to bring together all the features into "v1" rather than suffer from bolt on features and shoehorned syntax down the road.