[Cuis] Is Smalltalk right for my autonomous car? (was Re: Audio and Video Object Analysis)

[Frank Shearar]

On 18 December 2013 14:37, Kirk Fraser <overcomer.man at gmail.com> wrote:
> Thanks for the discussion. I didn't know C++ was so bad.  Is there any
> negatives about Python?

Just the same as with Ruby and Smalltalk: it's relatively slow, and so on.

> On government, I think ADA is about as dead as Cobol.  They aren't requiring
> it in the DARPA Robotics Challenge.  But I did see on comp.lang.Smalltalk
> where one huge government project in Smalltalk failed because they couldn't
> stop an unwanted ship from appearing in a simulation or something like that.
> So they went to C.

Was that JWARS or something? I know the DoD or similar had a huge
battlespace simulator written in Smalltalk.

> On a vehicle, the worst times I can imagine for a GC of even one second is
> just before a decision is needed to round a corner or stop.  Is there a way
> to fan out GC's so they are more frequent but less time consuming?  Perhaps
> a millisecond every second - let's see at 60 mph that would be 316800 feet
> per hour, 88 feet per second, 0.088 feet per millisecond or 1.056 inches.
> The Google car shoots for 1 cm accuracy - 1 in. is close enough.  So a
> garbage collection of one second means 88 feet off course but a millisecond
> would work.

More frequent GCs certainly help. Or you could talk the Erlang
approach, where each process has its own stack, and its own GC. That
means that when a process does need to GC, it has only a small amount
of memory to walk, so GC pauses are very short.

But really, I'd take the approach of not worrying about such a thing
now. I've never seen a GC of a second on any Smalltalk image. The
worst I've seen has been ~100 milliseconds.

frank