[squeak-dev] [Q] About VM and image formats

K K Subbu kksubbu.ml at gmail.com
Mon Sep 9 06:04:52 UTC 2019


On 08/09/19 10:06 PM, H. Hirzel wrote:
> I do not know or I forgot  if it is possible to open a 32bit image 
> with a 64 bit VM and thus convert the 32 bit image to 64 bit.

Yes, with restrictions. It is possible to open a 32b image on a 64b host 
but it needs a 32b VM and 32b compatibility libraries and the VM will 
not save the image in 64b format.

AFAIK, a VM can be compiled to edit 32b or 64b image but not both.

A 32b compiled VM can run on a 32b or 64b host but it can open a 32b 
image only. A 64b VM runs only on 64b host can edit a 64b image only.

32b host  = 32b VM (e.g. cogspur) edits 32b image
64b host  = 32b VM (e.g. cogspur) edits 32b image, or
             64b VM (e.g. cogspur64) edits 64b image.

The first 64b image was carved out by SystemTracer app running on 
32bVM+32b image using some magic incantations and supercow powers ;-).

Also, 32b or 64b images come in many formats and each format requires 
its own VM (see ImageFormat class).

HTH .. Subbu


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