To be live or not to be live!

Jecel Assumpcao Jr jecel at
Tue Apr 23 15:39:22 UTC 2002

On Monday 22 April 2002 20:27, Bruce Cohen wrote:
> One of the reasons the Smalltalk-based oscilloscopes made by
> Tektronix were such a successful product was *because* you could be
> confident there were no memory leaks.  

Well, you can have memory leaks in Smalltalk just by having objects you 
don't expect (undo buffers and other stuff) holding on forever objects 
you think were eliminated. But this is serious enough that we make the 
effort to deal with it most of the times people come across this 

We don't have dangling pointers, which are even nastier.

> Electronic instruments like
> oscilloscopes are often used in long-running measurements (hours,
> days. weeks-long sometimes) where it can be very inconvenient, even
> downright disastrous to an experiment to have to restart the
> equipment. 

The ideal living system shouldn't have to be restarted even while being 
upgraded. I think we will get there, eventually.

> So not having to worry about the firmware memory (which
> is usually pretty small to start with) filling up and hosing the
> scope's sampling controller or user interface is a very important
> feature.

Yes, the "low space notifier" is likely to show up only during 
development, not during normal use.

> I like to think that if it weren't for Ada (and you think Java is
> bad!), Smalltalk might have become the common language for avionics
> for this reason among others.

I am not sure that the hardware was up to it (though a custom 68030 
board was no problem for those kinds of applications...).

-- Jecel

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