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Comment by mattmanser | Hacker News Reader

I've half a blog post written about this that I'll probably never finish.

Given how much memory, disk space, etc. we have these days it's getting to the point that we should really have the ability to dump a program's state and all actions from starting the program to finishing it and then fast forward/rewind the actions of the user. Inspect all the locals, see what's actually happening. Set a loop over 30 seconds. Bugs would be a lot easier to find and recreate.

A bit like lightbox, but for debuggers!

It's just that no-one's done it yet and no programming language is really written to do it.

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Isn't this what omniscient debugging is? http://www.lambdacs.com/debugger/

Great quote from that page, "The ODB is as close to a silver bullet as you can get. Why don't people use it?"

Last I checked, OCaml had a replay debugger -- one which lets you step backwards.

And I know the mozilla guys sometimes use chronicle-recorder to fully record a running application for debugging. (It was referenced in a bug I filed.)

  http://code.google.com/p/chronicle-recorder/

Does anyone have experience using Chronon?

http://chrononsystems.com/

It is billed as "DVR for Java."

> Given how much memory, disk space, etc. we have these days it's getting to the point that we should really have the ability to dump a program's state and all actions from starting the program to finishing it and then fast forward/rewind the actions of the user.

Given a program from 20 years ago this is definitely possible. Given a program from today, it becomes an intractable problem quite quickly.

> It's just that no-one's done it yet and no programming language is really written to do it.

Live programming might get you what you want, but it won't be through brute force tracing of everything. Better to focus on deterministic replay then its quite easy to rebuild the contexts we need to fake it.

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