How About an InstallSqueak Image?

Andres Valloud sqrmax at cvtci.com.ar
Wed Jun 16 02:54:08 UTC 1999


Hi.

> It would appear that the only missing piece is how to glue arbitrary data 
> (installer image and compressed files) onto the end of an executable file 
> (a Squeak VM) in such a way that the host OS will only load the first part, 
> and won't be unhappy about the presence of the second part.

**Wintel**

There are a lot of utilities that can glue anything to the end of an
exe file, including the grotesque:

copy first.exe /b + garbage.files /b + ... + last.garbage /b
destination.file.exe

The result is that first.exe's header points to places that are still
valid, and the rest is ignored by the loader OS. This works since DOS,
the added stuff is treated as if it was an overlay, and so it's not
loaded until the exe needs it (never).

> We discussed this briefly over a year ago WRT single-file apps and there was 
> concern at the time that this approach would run afoul of many virus 
> protection schemes.  Anyone know what's possible and what's not here?

**Wintel again**

The overlay will not contain viral code, so errors here would be the
well-known false alarms triggered by heuristic procedures of the
antivirus. This has improved a lot lately and so it shouldn't be a
problem anymore. 

If the antivirus is set to be paranoid, it will certainly go and trace
the exe (if it has such an ability, most should do this), just to
discover that the overlay is "dead" data and so it will leave the
stuff, whatever it is, alone.

Andres.





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