memory allocation on commandline

Andreas Raab andreas.raab at
Sun Jan 19 14:28:53 UTC 2003


> Andreas, when did the Windows VM stop looking at the -memory
> switch? Was it before the 3.2 VM?

Essentially at the point where the support for growing/shrinking of the OM
was added (I think this was before 3.2 but I'm not sure). Ever since then
the VM has effecticely ignored what you say in -memory (not literally - but
after the first full GC the system is back to where it would be if you had
omitted -memory). I believe you can still get -memory to have an effect if
you turn off virtual memory management in the VM at which point it will just
malloc() the portion requested. But I haven't even tried this in ages.

  - Andreas

> -----Original Message-----
> From: squeak-dev-bounces at 
> [mailto:squeak-dev-bounces at] On 
> Behalf Of John Maloney
> Sent: Sunday, January 19, 2003 2:35 PM
> To: The general-purpose Squeak developers list
> Subject: Re: memory allocation on commandline
> Tim,
> What's in that tea you're drinking? :-> :->
> I'm sure that the Mac VM was *always* a total memory setup, 
> but you may
> have interpreted things differently when you did the Acorn port.
> On machines with virtual memory--or so much real memory than you don't
> need to worry about it--specifying the amount of free memory that you
> want after the image is installed may make sense. But implementing it
> could be a bit tricky, since a number of things are done at 
> startup time that
> expand the storage requirements. For example, the Display is 
> allocated to
> be the size of the window, and at 16-bit or 32-bit depths 
> that adds many
> megabytes. In addition, Form objects are compressed 
> ("hibernated") before
> the image is saved, and they get expanded on demand as you use
> them. Thus, the amount of space a given image on the disk will need
> when it is fired up is hard to predict. You basically have to 
> run the image
> to find out.
> I think the new mechanism to automatically grow the object heap has
> made this issue moot on platforms that have the proper virtual memory
> model. On other platforms, my personal inclination is to retain the
> current behavior of specifying the total memory, partly just because
> it's what I'm used to and expect.
> Andreas, when did the Windows VM stop looking at the -memory
> switch? Was it before the 3.2 VM?
> 	-- John
> Re:
> >> Ian and Andreas will probably have opinions about the *nix 
> and Win32
> >> VM's, but I seem to recall that "-memory" used to mean the 
> total memory
> >> allocation on these platforms as well, up through 2.8 at least...
> >It's wierd; my code and the variable names I used clearly 
> imply the idea
> >of headroom rather than total room, but the oldest sources I 
> have only
> >go back to 2.6 and that is indeed a total-room setup. Am I imagining
> >things? Could be... too many cups of tea can do that to you. I can
> >easily make it so that it works 'my' way on Acorns but I am 
> interested
> >in how people feel it ought to work as well.
> >
> >tim

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