On Mon, 11 Jul 2011, commits at source.squeak.org wrote:

> Bert Freudenberg uploaded a new version of System to project The Trunk:
> http://source.squeak.org/trunk/System-bf.446.mcz
>

snip

> Item was added:
> + ----- Method: SmalltalkImage>>okayToSave (in category 'snapshot and quit') -----
> + okayToSave
> + 	| wasCog isCog |
> + 	[wasCog := self imageFormatVersionFromFile allMask: 1]
> + 		on: Error do: [:ignore | "probably save-as to non-existing file" ^ true ].

You can also omit the argument.

> + 	isCog := Smalltalk isRunningCog.
> + 	^wasCog = isCog or: [
> + 		self confirm: 'Images saved under Cog cannot be opened on an interpreter again!!
> + Really save?']

It's not entirely true. The latest release of Unix and Mac interpreter VMs 
can read Cog images. Also if there were a new Windows VM released using 
the current VMMaker, it would also be able to open images saved with Cog. 
The proof is the VM that I built a few month ago 
(http://leves.web.elte.hu/squeak/SqueakVM-Win32-4.4.9-2358-non-official-bin.zip 
), because I had to read old ImageSegments into a Cog image which were not 
readable by Cog VMs.


Levente