"3 + 4" image

[Brian Rice]

Tonight, I discovered that if you go into build.slate and replace the  
#bootstrapFilenames file list in Image Definition with just one file,  
and then put "3 + 4" in that file, you can do a successful bootstrap  
and get a 104kb image output that does just that - adds two numbers.  
This is a legendary kind of super-minimalization for Smalltalk  
images, so I thought I'd check out the Slate possibility. It was  
really easy, and there were no snags.

So for now that is the lower bound on image size. Tthe remaining  
100kb consists of a lot of VM table linkage and primitive specs as  
well as a symbol table that could probably be cut down further. I  
haven't dug into it in detail, but I'm guessing that building a VM  
with fewer modules would allow the table to be smaller so a smaller  
output image. This isn't really a priority right now, but I wanted to  
know for sure what the situation was. Probably it indicates the  
general VM<->Image surface area, and I might use it as a metric for  
future simplifications.

Anyway, try it yourself if you dig that kind of thing. I may shortly  
write up some image-generation demos and save them in the repository  
for reference.

Future possibilities: a tool that can scan image files to see what  
object tree they have and explore it. Or, a tracer-based image  
definition builder, to take an arbitrary program and determine  
conservatively the minimum set of supporting structure it needs to  
run, stand-alone. Or, a way to embed the image into the VM as a build  
option so that the VM+image appear as a single binary transparently  
(pretty easy, really - just modifies boot.c).

--
-Brian
http://tunes.org/~water/brice.vcf

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